JPH038165A - Rotary drum device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotating drum device used in a magnetic recording/reproducing device that obliquely records/reproduces signals on a magnetic tape.

BACKGROUND OF THE INVENTION In recent years, this type of rotating drum device has been moving toward wide-angle winding of magnetic tape in order to make magnetic recording and reproducing devices smaller and lighter.

As a conventional rotating drum device, for example,
It is shown in Japanese Patent No. 88357.

A conventional rotating drum device will be explained below.

FIG. 6 shows a sectional view of this conventional rotating drum device. In FIG. 6, 1 is a magnetic tape, which is wound around a rotating drum 2 that rotates counterclockwise when viewed from above, and a fixed drum 4 that has a spiral guide 3 on its outer periphery, and is wound in the same direction as the rotating drum 2. Drive to. FIG. 7 is a plan view of a conventional rotating drum, in which a head base 5 having a magnetic head 6 at its tip is fixed to the rotating drum 2. As shown in FIG. Further, the rotating drum 2 is attached to a disk 8 that is integrated with a main shaft 7 shown in FIG. 6, and the main shaft 7 is rotatably held by two bearings 9.

Further, a plurality of spiral grooves 10 as shown in FIG. 7 are provided on the lower end surface of the rotating drum 2, and there is a slight gap [S] between the upper surface and the upper surface of a ring-shaped part 11 formed integrally with the fixed drum 4. I keep it.

The operation of the rotating drum device configured as described above will be described below.

First, when the magnetic tape 1 runs while being wrapped around the rotating drum 2 and the fixed drum 4, and the rotating drum 2 rotates in the direction of arrow a in FIG. 7, an air layer is formed between the magnetic tape 1 and the rotating drum 2. The magnetic tape 1 floats from the rotating drum 2 and travels. However, as shown in Figure 9A, this floating characteristic decreases from the tape entrance to the tape exit, and the flying height is particularly small from the center of the tape winding to the tape exit.
There is a possibility that the rotating drum 2 and the magnetic tape may come into contact with each other.

Therefore, in order to increase the floating of the magnetic tape J, a plurality of spiral grooves 10 are provided on the lower end surface of the rotating drum 2. In other words, as the rotating drum 2 rotates in the direction of the arrow in FIG.
The air between them also moves in the same direction, but the rotating drum 2 is relatively faster, and the relative movement of the air with respect to the rotating drum 2 is in the direction of arrow C in FIG. The air collides with the sidewall 1 of the spiral groove 10 provided on the rotary drum 2 and is discharged in the direction of arrow d, generating dynamic pressure for floating the magnetic tape 1.

The magnetic tape 1 is reliably floated above the rotating drum 2.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, since the tape flying height increases uniformly from the tape entry side to the tape exit side,
The tape floating height from the tape entry side to the tape exit side is 9th.
As shown in the figure A, the flying height distribution becomes uneven (large at the tape entrance, small at the tape exit), and the contact pressure between the magnetic head 6 and the magnetic tape 1 decreases, especially on the tape entry side where the flying height is large, which is good. There is a certain point where you cannot get a proper head touch.

The non-uniform flying height distribution becomes more pronounced as the winding angle of the magnetic tape 1 becomes larger, and when winding a tape at 270 degrees, which is used for a camera-integrated video camera, etc., the population of the magnetic tape 1 becomes smaller at the exit. The problem is that the flying height further increases, and the contact pressure between the magnetic head 6 and the magnetic tape 1 on the tape entry side further decreases, making it increasingly difficult to obtain a good head touch.

The present invention solves the above conventional problems, and provides a rotating drum device that makes the flying height uniform from the tape inlet to the tape outlet and improves the contact between the magnetic tape 1 and the magnetic head 6 even in wide-angle tape winding. The purpose is to provide.

Means for Solving the Problems To achieve this object, the rotating drum device of the present invention comprises:
A rotating drum with a flat surface on the lower end surface, and a spiral structure in a position opposite to the flat surface of the rotating drum, the section from the entrance of the magnetic head scanning the magnetic tape to the center is configured to suck air into the drum. The groove and the section from the center of the magnetic head scan to the exit have a stationary drum provided with a spiral groove configured to expel air out of the drum.

Effect of the present invention With the above-described configuration, the section from the entrance to the center of the magnetic head scanning forms a spiral groove that sucks air into the drum. The flying height of the tape from the tape entry side to the center can be reduced, and the contact pressure between the magnetic disk 6 and the magnetic tape j from the entry side to the center can be increased to obtain a good head touch. In addition, by providing a spiral groove in the section from the center of the magnetic head to the exit of the drum so that air is discharged to the outside of the drum, dynamic pressure is generated to levitate the magnetic tape 1, and the magnetic tape 1 is transferred to the rotating drum 2. It is definitely rising from the ground.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a sectional view of a rotating drum device in an embodiment of the present invention. In FIG. 1, reference numeral 12 denotes a magnetic tape, and as shown in FIG.
It wraps around itself and runs. 16 is a head base having a magnetic head 17 at its tip;
It is fixed at 0 degree division. Further, the rotating drum 13 is attached to a disk drive 9 that is integrated with a main shaft 18, and the main shaft 18 is rotatably held by two bearings 2o. Further, the lower end surface of the rotating drum 13 is provided with a flat surface 21 as shown in FIG. 2, and the upper end surface of the fixed drum 15 is provided with 2W type spirals #22a and 22b as shown in FIG.

22 c, 22 d, 22 e and 23a, 23
b, 23c.

23d and 23e are provided, and the plane 21 and the spiral groove face each other with a distance t shown in FIG. 1 being maintained. Further, a rotor 26 is attached to the main shaft 18 via a bearing presser 24 and a spring member 25, and a stator unit 27 is attached to the fixed drum 1 inside the rotor 26.
It is integrated with 5.

The operation of the rotating drum device of this embodiment configured as described above will be explained below.

First, the magnetic tape 12 is connected to the rotating drum 13 and the fixed drum 1.
When the rotating drum 13 rotates in the f direction, an air layer is formed between the magnetic tape 12 and the rotating drum 13 as in the conventional example, and the magnetic tape 12 The rotating drum 13 has characteristics similar to A in Figure 9.
It floats up and runs. Then, the rotating drum 13
Rotating drum 13 and fixed drum 1 when rotated in direction f in the figure.
5 (t in FIG. 1) also moves in the direction g in FIG. 4, and some of the air moves in the direction g in FIG.
d.

22e side walls 28a, 28b, 28c, 28d.

28e and flows in the direction of the arrow. And this h
The flow in this direction draws the air outside the drum in the direction of arrow i, and as the rotating drum 13 rotates, the magnetic tape 1
2 is reduced from the tape entrance to the center as shown in FIG. Also, part of the air moving in the g direction flows through the spiral groove 23a provided in the fixed drum IS.

23 b, 23 c, 23 d, 23 e
side wall 29a.

29 b, 29 c, 29 d, 29 e
The flow in the j direction acts as if discharging the air inside the drum to the outside, generating dynamic pressure to levitate the magnetic tape 12, as shown in FIG. The magnetic tape 12 can be reliably floated from the rotating drum 13 from the tape center to the exit. If the pitch of the spiral grooves is made dense enough to reach the tape entrance or exit as shown in Figure 3, the tape flying height from the tape entrance to the tape exit can be made uniform as shown in Figure 9. I can do seven things.

Effects of the Invention As described above, the present invention provides a rotating drum having a flat surface on its lower end surface, and a section of the rotating drum that faces the flat surface from the entrance to the center of the magnetic head for scanning the magnetic tape. Wide-angle tape winding is possible by using a fixed drum with a spiral groove configured to suck air into the drum, and a spiral groove configured to expel air from the center of the magnetic head scan to the exit outside the drum. Even in rotating drum devices, tape floating from the tape entrance to the center can be reduced.
Since sufficient contact pressure can be ensured at the tape entrance of the magnetic head 17, head touch especially at the tape entrance can be improved. Furthermore, since the difference in flying height from the tape entrance to the tape exit can be eliminated and a uniform flying height can be achieved, the held touch conditions from the tape entrance to the tape exit can be kept the same, and stable recording and reproduction signals can be obtained.

In addition, by achieving a uniform flying height, reliable head touch can be ensured with a small head protrusion amount, which has great effects such as suppressing wear on the head and extending its life.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotating drum device according to an embodiment of the present invention, FIG. 2 is a plan view of a rotating drum of the present invention, FIG. 3 is a plan view of a fixed drum of the present invention, FIGS. The figure is an explanatory diagram of the air flow in the spiral groove provided in the fixed drum, Figure 6 is a sectional view of a conventional rotating drum device, and Figure 7 is a plan view showing the spiral groove provided in the rotating drum of a conventional rotating drum device. , FIG. 8 is an explanatory diagram of the air flow of the conventional spiral groove,
FIG. 9 is a characteristic diagram showing the tape flying height. 12... Magnetic tape, 13... Rotating drum, 1
5... fixed drum, 17 magnetic head, 21...
・Plane part, 22a, b+ C+ ct,
e...Spiral groove, 23a, b+c
, cL e--Spiral groove.

Claims (1)

[Scope of Claims] A rotating drum equipped with a magnetic head and having a flat part on its lower end surface, and a section of the magnetic head from an entrance to the magnetic tape to the center located at a position opposite to the flat part of the rotating drum. A rotating drum device characterized by having a fixed drum having a spiral groove configured to suck air into the drum, and a fixed drum provided with a spiral groove configured to discharge air outside the drum in the section from the center to the outlet. .