JP3106594B2 - Rotating head cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a case where a notch provided for projecting a magnetic head to the outside of a cylinder during rotation of a cylinder passes near an upper and lower cylinder connecting member provided for fixing an upper cylinder. The present invention relates to a rotary head cylinder that reduces noise caused by air turbulence generated when the tape enters a tape.

[0002]

2. Description of the Related Art In recent years, miniaturization, high image quality, and high sound quality of analog VTRs have been advanced, and the necessity of developing a portable type for a digital VTR has greatly increased. However, digital VTRs require a higher recording density than analog VTRs, so the cylinders have a structure in which a rotating cylinder is sandwiched between fixed cylinders, and the rotation speed is very high, about 6000 rpm. The notch provided for the magnetic head mounted on the cylinder to protrude outside the cylinder passes at high speed with the rotation of the cylinder, near the tape entry point and near the upper and lower cylinder connecting members provided for fixing the upper cylinder. Therefore, turbulence of the air flow occurs, and noise caused by the air turbulence is taken in from the recording microphone during recording, which causes a problem that the sound quality is deteriorated.

A conventional rotary head cylinder for a digital VTR will be described below. FIG. 1 is a perspective view of the rotary head cylinder as viewed from the direction in which the tape enters the cylinder. In FIG. 1, reference numerals 1 and 3 denote upper and lower fixed cylinders, and the upper cylinder 1 is fixed to the lower cylinder by a connecting member 8. Reference numeral 2 denotes a rotary cylinder provided therebetween, and a magnetic head 6 is provided between the fixed lower cylinder 3 and the fixed lower cylinder 3 in such a manner that the tip protrudes outside the notch 7 by about 30 μm. It rotates in the direction indicated by A. The magnetic tape 4 is spirally wound around the outer peripheral surface of the cylinder by the post 5 and advances in the direction shown by the arrow B. The magnetic head 6 enters the tape 4 from the lower edge of the tape 4 and starts recording and reproduction. FIG. 4 is an enlarged view of a main part of the rotary cylinder where the magnetic head mounting portion is viewed obliquely from below. Reference numeral 9 denotes a head base that supports the magnetic head 6, and the base portion is fixed to the rotary cylinder 2. When assembling the cylinder, the lower surface of the outer peripheral portion of the rotary cylinder 2 is
And the upper surface of the outer peripheral portion of the rotary cylinder are combined at a constant interval of about 150 μm, so that the area where the cylinder internal space is opened to the outside of the cylinder at the cutout portion 7 is not It will expand rapidly in comparison.

[0004]

However, in the above-described conventional configuration, in the portion where the tape 4 is not wound around the cylinder, the internal space of the cylinder is largely opened to the outside of the cylinder due to the centrifugal force caused by the rotation of the rotary cylinder 2. An airflow is generated in a direction flowing out from the notch 7, and when the notch 7 passes through the connecting member 8, an air vortex is generated near the connecting member 8. Further, in the portion where the tape 4 is wound around the cylinder, since the high-pressure air film is generated by the air which is wound on the surface of the rotary cylinder 2, the tape 4 flows in from the notch portion 7 in reverse to the portion where the tape is not wound. An airflow is generated in the direction, and when the notch 7 enters the tape 4, a sudden reversal of the airflow direction occurs, and an air vortex is also generated in that portion. The noise is generated due to the air turbulence caused by the vortex of the air, and particularly in a portable VTR in which a microphone and a traveling system part are integrated, the noise is directly taken from a recording microphone, There is a problem that the sound quality is deteriorated.

An object of the present invention is to solve the above-mentioned conventional problems and to provide the above-described noise reduction effect.

[0006]

In order to achieve this object, a rotary head cylinder according to the present invention is provided with a notch provided for a magnetic head mounted on the rotary cylinder to protrude outside of the cylinder. A head cover is provided to shield the inside of the cylinder, which is open to the outside of the cylinder by the cutout portion, from the outside of the cylinder.

[0007]

With this configuration, it is possible to suppress air disturbance that occurs when the notch 7 passes through the connecting member 8 and when the tape enters, and it is possible to reduce noise caused by the air disturbance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 10 in FIG. 2 denotes a head cover provided in the notch 7, which can shield the cylinder internal space opened to the outside of the cylinder by the notch 7 when assembling the cylinder from the outside of the cylinder. It is possible to suppress the flow of air through the notch 7 that occurs, and it is possible to suppress noise caused by air turbulence generated when the notch 7 passes near the connecting member 8 and enters the tape. In order to obtain the same effect as the above-described head cover, a method of sealing the cutout portion 7 with resin or the like can be considered, but it is desirable to use a detachable head cover in consideration of adjustment and replacement of the magnetic head. In addition, the above-mentioned head cover can also be used as a shield cover for electrically shielding the head from external noise. The same effect as the above-mentioned head cover can be obtained by making the shield cover having the desired effect even if it has a gap with a sealing structure except for the head projecting portion, and reducing the noise due to air turbulence. Becomes possible. It has been confirmed that noise can be reduced by about 5 dB by taking the above measures.

[0009]

As described above, according to the present invention, in a rotary head assembly of a VTR in which a rotary cylinder is provided between a fixed upper cylinder and a lower cylinder, the recording head mounted on the rotary cylinder projects outside the cylinder. Is provided with a head cover that shields the internal space of the cylinder opened to the outside of the cylinder by the notch when the cylinder is assembled, so that the notch 7 passes through the connecting member 8 and the tape. It is possible to suppress the air turbulence that occurs at the time of entry, and to realize a rotary head cylinder that can reduce noise caused by the air turbulence.

[Brief description of the drawings]

FIG. 1 is a perspective view of a rotary head cylinder.

FIG. 2 is an enlarged view of a magnetic head portion of a rotary head cylinder in one embodiment of the present invention.

FIG. 3 is an enlarged view of a magnetic head portion of a rotary head cylinder in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper cylinder 2 Rotating cylinder 3 Lower cylinder 4 Tape 5 Post 6 Magnetic head 7 Notch 8 Upper and lower cylinder connecting member 9 Magnetic head base 10 Head cover

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Taku Kosai 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (56) References JP-A-2-198002 (JP, A) JP-A-61-187037 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 15/61 G11B 5/53

Claims (1)

(57) [Claims] 1. A coupling set a fixed cylinder and rotating cylinder
In a rotating head assembly of a VTR, a rotating cylinder having a notch provided for projecting a magnetic head to the outside of the cylinder has a cylinder internal space opened to the outside of the cylinder by the notch when the cylinder is assembled. Is shielded from the outside of the cylinder and inside the cylinder.
Rutotomo the head cover is provided so as to cover the head portion
The head cover is a shield cover for blocking electromagnetic waves.
Rotary head cylinder, characterized in that the chromatography.