JP2547598Y2 - Rotating head drum - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION This invention relates to a rotary head drum, in particular, a magnetic head is fixed to a drum, a magnetic tape is wound around the drum, and the drum is rotated while running. The present invention relates to a rotary head drum for recording and reproducing information by scanning a magnetic tape with a magnetic head.

2. Description of the Related Art In a rotary head type magnetic recording / reproducing apparatus, recording / reproducing is performed by rotating a magnetic head while running while rotating a magnetic tape around a rotary head drum to which a magnetic head is fixed and running.

Such a rotary head drum usually includes an upper drum and a lower drum, and a magnetic head is fixed to the upper drum and rotated to fix the lower drum.

When such a rotary head drum is rotated, the magnetic tape is drawn into the gap between the upper drum and the lower drum, and the magnetic tape and the magnetic head come into close contact with each other. Since the upper drum rotates and has a high relative speed with respect to the magnetic tape, there is a problem in that the portion of the upper drum that is in contact with the magnetic tape affects the damage to the magnetic tape. Therefore, as shown in FIG. 3, the peripheral edge 19 of the upper drum 18 has been chamfered.

However, in the conventional rotary head drum, the chamfer of the edge on the lower side of the rotary drum, that is, on the side facing the fixed drum, is only once under the notch for the magnetic head. Therefore, the chamfered portion becomes a relatively deep angle with respect to the drum surface. When the magnetic tape is pulled in when the drum is rotated, the magnetic tape is damaged at the corner between the chamfered portion, the bottom surface, and the drum surface.

The present invention has been made in view of the above points, and has as its object to provide a rotary head drum that does not damage a magnetic tape.

Means for Solving the Problems The present invention provides a rotating head drum in which a magnetic head is fixed so as to protrude from an opening which is opened upward from a lower end of an outer peripheral surface of a drum, and an upper end of the opening on an outer peripheral surface of the drum. A chamfered portion chamfered from above to the lower end of the drum outer peripheral surface; a mirror-finished portion formed directly above an upper end of the chamfered portion on the outer peripheral surface of the drum; and a lower end of the chamfered portion. And a peripheral edge formed by a plurality of conical surfaces formed continuously with different inclination angles with respect to the rotation axis of the rotary head drum.

According to the present invention, the angle between the chamfered portion and the drum surface can be reduced because the chamfered portion and the drum surface are chamfered from the upper end of the opening on the outer peripheral surface of the drum to the lower end of the outer peripheral surface of the drum. Therefore, damage to the magnetic tape is eliminated. In addition, by forming the peripheral edge of the lower end of the chamfered processing portion with a plurality of conical surfaces continuously formed with different inclination angles with respect to the rotation axis of the rotary head drum, a surface close to a curved surface is formed. Therefore, the angle of the tip portion caused by the reduced angle of the chamfered portion does not stand, and the intersection between the opening and the tip portion has no corner. It has features such as no damage. Further, the processing of the lower end of the chamfered processing portion can be easily performed as compared with the curved surface processing.

FIG. 1 is a sectional view and a front view of a main part of an embodiment of the present invention, and FIG. 2 is a sectional view of an embodiment of the present invention.

Reference numeral 1 denotes a magnetic head which is fixed to a head base 2.
The magnetic head 1 is arranged symmetrically with respect to the rotation axis 8. The magnetic head 1 is electrically connected to a head base 2. The head base 2 is fixed to the upper drum 4 by a fixing screw 3,
The magnetic head 1 is fixed so as to slightly protrude from an opening formed in the upper drum 4. The head base 2 is deflected by the adjusting screw 5 screwed into the upper drum 4, and the magnetic head 1 is bent.
The position can be adjusted.

The upper drum 4 is fixed to the rotating flange 7 by screws 6. The rotating flange 7 is fixed to a rotating shaft 8. Rotary axis 8
Is fixed to a rotor 9a constituting the motor 9. Motor 9
The stator 9b is fixed to the lower drum 10. The motor 9 constitutes a brushless motor.

A rotary transformer 11a is fixed to the fixed flange 7 fixed to the rotating shaft 8. Rotary transformer 11a is wire rod 12
Is electrically connected to a substrate 12 fixed on the upper surface of the upper drum 4. Also, the rotary transformer 11a of the lower drum 10
The rotary transformer 11b is fixed at a position facing the
The wire 13 connects to an external circuit. The cross section of the peripheral portion of the upper drum 4 facing the lower drum 10 is chamfered into a shape as shown in FIG. The magnetic head 1 is chamfered from above the upper end of the opening portion 14 from which the magnetic head 1 protrudes. The upper portion 17 of the chamfered portion 15 is mirror-finished and processed so as not to generate burrs and the like.

The chamfered portion 15 is chamfered in the direction of the arrow A to 1.5 [mm] in the direction of the arrow B in the order of 5 to 10 [μm] and has a shallow angle with respect to the drum surface. No burrs appear at the boundary between the drum surface and the chamfered portion 15, and the magnetic tape is not damaged.

When the upper drum 4 rotates, the magnetic tape is drawn from the gap between the upper drum 4 and the lower drum 10 toward the center of the drum. At this time, since the lower drum 10 is fixed and the relative speed with respect to the magnetic tape is small only by the running speed of the magnetic tape, the peripheral portion does not cause much damage to the magnetic tape. However, since the upper drum 4 rotates at a high speed of 1800 rpm or more, the relative speed with respect to the magnetic tape is large, and the corners and burrs of the peripheral portion are large, which affects the damage to the magnetic tape. However, in this embodiment, since the peripheral portion 16 of the upper drum 4 is processed into an arc shape by four-chamfering processing, no damage is given to the magnetic tape. Also,
In particular, at the intersection between the opening 14 and the peripheral edge 16, the peripheral edge 16 is processed into an arc shape so that no corner is formed, which is effective against damage to the magnetic tape.

In the present embodiment, the peripheral portion 16 is chamfered by four chamfers. However, the present invention is not limited thereto.

Effect of the Invention As described above, according to the present invention, the chamfered portion including the opening surface is chamfered from the upper end of the opening on the outer peripheral surface of the drum to the lower end of the outer peripheral surface of the drum. The angle can be made shallow, and damage to the magnetic tape is eliminated.

In addition, by forming the peripheral edge of the lower end of the chamfered processing portion with a plurality of conical surfaces continuously formed with different inclination angles with respect to the rotation axis of the rotary head drum, a surface close to a curved surface is formed. Therefore, the angle of the tip portion caused by the reduced angle of the chamfered portion does not stand, and the intersection between the opening and the tip portion has no corner. It has features such as no damage. Further, the processing of the lower end of the chamfered processing portion can be easily performed as compared with the curved surface processing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of one embodiment of the present invention, FIG. 2 is a cross-sectional view of one embodiment of the present invention, and FIG. 1 ... magnetic head, 4 ... upper drum, 10 ... lower drum,
14 ... opening, 15 ... chamfered part, 16 ... ... peripheral part.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akihiko Yasutake 958-1 Itado, Isehara City, Kanagawa Prefecture Parkheim 1 Room 201 (72) Inventor Hirotoshi Sekiguchi 2-6-1 Mizuhiki Atsugi City, Kanagawa Prefecture No. 402 (56) References JP-A-54-12809 (JP, A) Jpn.

Claims (1)

(57) [Scope of request for utility model registration] 1. A rotary head drum, wherein a magnetic head is fixed so as to protrude from an opening which is opened upward from a lower end of an outer peripheral surface of the drum, wherein the outer periphery of the drum is provided from above an upper end of the opening on an outer peripheral surface of the drum. A chamfered portion chamfered toward the lower end of the surface; a mirrored portion formed directly above an upper end of the chamfered portion on the outer peripheral surface of the drum; and a rotation of the rotary head drum at a lower end of the chamfered portion. A rotating head drum comprising: a peripheral portion formed by a plurality of conical surfaces continuously formed with different inclination angles with respect to an axis.