JPS61267958A - Rotary head drum device - Google Patents

Abstract

PURPOSE:To obtain good head touch extending over the whole scanning section by making the upper opening end of a duct-shaped cylindrical body which is fixed to the lower part of a head, opposed to a tape, and providing a through- hole on one part of the fixed drum surface which has contacted on the lower opening end. CONSTITUTION:A head 6 and a duct-shaped cylindrical body 8 are fixed to a base 18 of the lower face of a rotary drum 1, and an upper opening end 8a of the cylindrical body 8, and a lower opening end 8b are opposed at an interval (h) to the lower part of the head 6, and a ring 12 on a fixed drum 2, respectively. The opening end 8a is inclined by a horizontal angle alpha against the outside peripheral surface of the drum, and when the drum 1 and the cylindrical body 8 rotates as one body, air flows in and the inside of the cylindrical body s kept at a prescribed static pressure. When the cylindrical body 8 comes to a position of one piece of through-hole 12a on the ring 12 provided on the inlet side of the drum and the static pressure drops, a tape opposed to the opening end 8a is attracted in the center direction of the drum. In such a way, it is prevented that the maximum bearing point between the head and the tape moves in the upper direction, and the output of the head can be secured stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a helical scan type magnetic recording/reproducing device, and particularly to a rotating head drum device suitable for stabilizing head touch.

[Background of the invention]

In a helical scan type magnetic recording/reproducing device, a magnetic tape is usually wound spirally around a rotating drum, and the tape is scanned by a fixed magnetic head that protrudes a predetermined amount in the radial direction from the outer circumference of the rotating drum. In a device that performs recording and reproduction by running the tape at a speed in a predetermined direction, the magnetic head moves the tape from the lower end (upper end) to the upper end ( Scan diagonally to the bottom edge). At that time, at both ends of the tape in the width direction, the width of the tape is lower than at the center of the tape.
The tension value is decreasing, and the bending deformation of the tape in the direction of the head thickness becomes asymmetrical, making it difficult to maintain the optimal contact state in which the tape is evenly pressed against the entire width of the head gap. , the head output decreases at the end of the tape.

In particular, the inlet side of the drum that hits the upstream button on the tape running bus (
On the entrance side of the head), the tape tension value is lower than on the exit side of the drum (exit side of the head), and the point where the contact surface pressure between the tape and the head is maximum moves above the core, increasing the head output. decrease becomes greater.

As a countermeasure to this problem, Japanese Patent Application Laid-Open No. 52-146608 discloses that by shifting the head gap upward from the center (in the thickness direction) of the core of the head, contact between the tape and the head is made on the entrance side of the drum. The point where the surface pressure is maximum is
Measures have been devised to ensure head output even when moving above the core.

However, although this measure improves the drum entrance side, it tends to cause a decrease in output at the drum exit side (at the drum exit side, the contact surface pressure between the tape and the head is at its maximum). (the point at which the output point moves downwards in the core), the margin for securing the output on the exit side becomes smaller. Also,
Due to wear of the head, the apex of the core (in the thickness direction) moves toward the head gap, resulting in a drawback that it is difficult to maintain initial performance over a long period of time.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary head drum device capable of obtaining a good head touch over the entire scanning period of the head with respect to the tape in such a helical scan type magnetic recording/reproducing device.

[Summary of the invention]

The present invention changes the deformation state of the tape located near the head to an optimal state by locally changing the airflow around the head in the output drop portion in the section where the head scans the tape. This is to improve the output drop in that area.

[Embodiments of the invention]

Hereinafter, F1 embodiments of the present invention will be explained with reference to g1 to FIG. 4.

FIG. 1 is a half-sectional view showing the assembly structure of a rotary head drum according to the present invention.

In FIG. 1, %1 is a rotating drum, and %2 is a rotating drum.

Fixed drum, 3 is a rotating shaft, 4% is a bearing for rotatably holding the rotating shaft 3 with respect to the fixed drum 2, 6 and 7 are fixed to the lower end surface of the rotating drum 1 with screws. A magnetic head 8.9 is fixed below the magnetic head, and a cylindrical body 10.11 rotates integrally with the rotating drum 1 and the magnetic head 6.7.A rotary transformer 12 is a stator. A ring 13 is fitted around the outer periphery of the side rotary transformer 11 and fixed inside the fixed drum 2. A boss 13 is fitted onto the rotating shaft 3 and holds the rotating drum 1. A boss 14 is a boss that holds the stator coil 15. Stator to hold, 1
Reference numeral 6 denotes a rotor to which a rotor magnet 17 is adhered and rotates once integrally with the rotating shaft 3.

FIG. 2 is a half-sectional view showing the component configuration around the head chip in the rotating drum assembly shown in FIG. 1. FIG.

In FIG. 2, the head base 18 to which the head chip 6 is adhesively fixed to one end has a stepped recess 18-a on the lower surface.
A duct-shaped cylinder 8 is adhesively fixed via an adhesive spacer 21 such that one open end 8-a thereof is located below the head chip. The other open end 8-A of the cylindrical body 8 faces the upper end surface of the ring 12 with a predetermined distance n maintained therebetween. FIG. show. A through hole 12-4 is provided in a portion of the ring 12. And ring 12 is
The rotary transformer 11 is housed on the outer periphery of the fixed drum 2 and fixed with adhesive so that the through hole 12-a is located at the entrance of the drum (the point where contact with the tape starts).

FIG. 4 shows the structure of the duct-shaped cylinder 8.

The upper open end 8- of the cylindrical body 8 is inclined at a predetermined angle a with respect to the circumferential direction of the outer peripheral surface of the rotating drum 1,
It's open. The inside of the cylindrical body 8 is still hollow toward the open end sb, as shown by the broken line.

Now, as shown in FIG. When rotating together with the head 6 in the direction indicated by the arrow, the opening 9-a at the upper end of the cylinder 8 forms an angle α with respect to the circumferential direction of the outer peripheral surface of the rotating drum, as described above. Due to its own inertia, the air located below the head 6 of the inclined cage hits the side wall of the opening 13-tL, flows into the interior of the cylinder in the direction of arrow B, and flows into the lower opening 8. - flows to b.

FIGS. 6 and 7 are cross-sectional views showing the state in which the rotating drum assembly configured as described above scans a tape.

In FIG. 6, air flowing from the opening 13-a of the cylinder 8 passes through the inside of the cylinder 8 as shown by the arrow and reaches the opening a-b below. Then, it flows into the drum through the gap between the opening 8-A and the upper end surface of the ring 12.

This gap is.

9 The viscosity of air is set to be sufficiently small compared to the viscosity of air, and the flow rate of air flowing out from the open end 8-b is restricted, and the air inside the cylinder 8 maintains a predetermined static pressure and rotates together with the cylinder. do.

As shown in FIG. 7, the opening 8-h of the cylinder 8 is
When passing through the upper part of the through hole 12-eL on the ring 12 provided on the entrance side of the drum assembly, the static pressure inside the cylinder is released to the through hole, so the pressure inside the cylinder is reduced. decreases. Along with this, the air pressure at the upper opening 3-a also decreases, and as a result, the tape facing the opening s8-α is sucked toward the center of the drum for one rotation.
This prevents the maximum contact surface pressure point between the head gap and the tape from moving upward, which tends to occur on the inlet side of the drum assembly.

〔Effect of the invention〕

As described above, according to the present invention, the deformation of the tape relative to the head is locally changed at the drum entrance, preventing the maximum surface pressure point between the head tapes from moving upward, and stabilizing the head output. This has the effect of ensuring security.

[Brief explanation of drawings]

Fig. 1 is a half-sectional view of a rotating drum assembly according to an embodiment of the present invention, Fig. 2 is a sectional view of the vicinity of the head, Fig. 3 is a perspective view showing the attachment of the ring, and Fig. 4 is a cylindrical body. , FIG. 5 is a perspective view of the head and cylinder, and FIGS. 6 and 7 are
FIG. 3 is a cross-sectional view of the tape and the peripheral portion of the head. 1... Rotating drum 2... Fixed drum 6.
...Head 8...Cylinder 12...Link 21...Spacer. 1st mouth 21st $-5 Yua 4th S country

Claims (1)

[Claims] 1. In a magnetic recording and reproducing device that performs recording and reproducing by winding a magnetic tape spirally at a predetermined angle around a drum assembly consisting of a rotating drum and a fixed drum, each of which is equipped with a plurality of magnetic heads. located below the
A cylindrical air circulation member having a first open end facing the magnetic tape and a second open end facing the side or lower surface of the inside of the fixed drum is provided, and the second open end A rotary head drum device characterized in that a part of an opposing surface inside the fixed drum is set further away from the second opening end than other opposing surfaces.