JPS6194257A - Rotary cylinder device - Google Patents

Abstract

PURPOSE:To secure the stable reproduced pictures by providing a wall to a rotary cylinder to prevent the reduction of air pressure in a space between upper and lower cylinders. CONSTITUTION:A wall 19 which lacks only the part where a magnetic head 6 is provided is provided to the lower side surface of a rotary cylinder 2 in almost a cylindrical form and at the slightly inner side from the outer circumferential surface of the cylinder 2. The cylinder 2 and a tape 25 have relatively high-speed motions and therefore an air lublicant layer is formed with a proper level of pressure. While no air layer is formed between a fixed cylinder 3 and the tape 25. Thus the tape 25 rubs the circumferential surface of the cylinder 3. As a result, the air layer formed between the cylinder 2 and the tape 25 is going to flow into a gap between both cylinders as well as toward the side of the cylinder 3. Here the wall 19 prevents the flow of the air and increases the air pressure between both cylinders. Thus the tape 25 is floated over a rotary cylinder device 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotating cylinder family in a magnetic recording/reproducing device, and particularly to a rotating cylinder device suitable for stably running a magnetic tape.

[Background of the invention]

Conventionally, the cylinder structure of the scanning section of a magnetic head in a magnetic recording/reproducing device has mainly been a rotating cylinder type. In this rotating cylinder system, for example, as described in Japanese Patent Publication No. 42-8665, a drum that guides the tape rotates at high speed to form a lubricating layer of air between the tape and the drum, thereby stabilizing the tape. However, even in this rotating cylinder system, the lubricating air layer decreases in the gap between the upper and lower cylinders near the rotation locus of the magnetic head, causing the tape to come into contact with the rotating cylinder. vibration and damage, resulting in deterioration of the reproduced image quality. This is particularly noticeable in thin, low-rigidity tapes that have been increasingly used in recent years.

To deal with this phenomenon, there is a method to make the lubricating layer of air even more stable by rotating the lower cylinder side as well, as in this conventional example, but there are problems with manufacturing costs and stability of tape running. [Objective of the Invention] The object of the present invention is to solve the above-mentioned disadvantages of the conventional example, to prevent the tape from being damaged by running, to provide a stable tape running condition, and to ensure good reproduced image quality. The object of the present invention is to provide a rotary cylinder device that can perform the following functions.

[Summary of the invention]

The present invention is characterized by focusing on the fact that the air flow in the gap between the upper and lower cylinders in a rotating cylinder device affects the formation of a stable air film between the tape and the cylinder, and prevents a decrease in air pressure in the gap between the upper and lower cylinders. Embodiment of the Invention An embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG. 2 is a perspective view showing a part of the tape running system in the rotary cylinder device. In the figure, 1 indicates a rotating cylinder device, which includes a rotating cylinder (upper cylinder) 2.
and a fixed cylinder (lower cylinder) 5.

A head window 5.5 is provided at the lower end of the rotary cylinder 2, as shown in FIG. 3, for exposing the tip of the magnetic head 6 to the outer peripheral surface of the rotary cylinder 2. Further, the fixed cylinder 6 is provided with an IJ-domain 4 in a spiral shape. lead 4
is for guiding the running of the tape 25 that is wound diagonally around the rotary cylinder device 1. 71 and 81 are inclined guides for winding the tape 25 around the rotary cylinder device 1 in a spiral manner, and 61 and 91 are guide rollers for changing the running direction of the tape 25. The rotating cylinder 2 is rotated in the direction of arrow A, and the tape 25 is passed through the tape traveling machine g (not shown).
By driving the magnetic head 6 in the direction of arrow B,
scans the tape 25 diagonally in sequence.

FIG. 1 is a sectional view of a main part of the rotary cylinder device 1, and FIG. 4 is a perspective view showing the structure of the rotary cylinder. In the figure, the fixed cylinder 3 has a cylindrical bearing support part 10 at its inner center.
are integrally formed. Bearings 8 and 9 are inserted into the upper and lower ends of the bearing support section 10, respectively, and rotatably supports the shaft 7. A disk 11 is press-fitted into the upper end of the shaft 7, a holder 14 is screwed to one of the lower ends, and the disk 11 and the holder 14 are screwed together.
The structure is such that appropriate preload is applied to the disk 11, holder 14, and bearings 8 and 9. A support member 15 is fixed to the lower end of the shaft 7, and a rotor 17 of the motor is integrally bonded to the support member 15. On the other hand, a support member 16 that supports a stator 18 of the motor is fixed to the lower end of the fixed cylinder 5. The stator 1B is disposed facing the rotor 17, and the shaft 7. The disk 11 and the rotating cylinder 2 screwed to the disk 11 are rotated at a predetermined angular velocity.

As described above, the rotary cylinder 2 is provided with a plurality of windows 5 on its lower end surface. A head base 21 having a magnetic head 6 fixed to its tip is fixed to the rotating cylinder 2 with screws 22 so that the magnetic head 6 protrudes from the window 5. Video signals are transferred to and from the magnetic head 6 using the fixed cylinder 3.
The rotary transformer 13 is fixed to the rotary transformer 13 and the rotary transformer 12 is fixed to the lower end of the disk 11 and faces the rotary transformer 13.

On the lower surface of the main rotating cylinder 2, a cylindrical wall 19 (19a, 19b') is provided slightly inside the outer peripheral surface thereof, with only the portion where the magnetic head 6 is installed removed. 25 (25a, 25b) are attached to the wall 19 in order to accurately attach the helad base 21 to the rotating cylinder 2.
Chill with a groove that forms a relief to ensure the flat part that has been removed. Reference numeral 24 denotes a hole for fixing the rotary cylinder 2 to a screw hole provided in the disk 11 with a screw 20.

FIG. 5 is a sectional view showing the state of the tape 25 wound around the rotary cylinder device 1. As shown in FIG. Rotating cylinder 2 and tape 25
Because it is moving at a relatively high speed, an aerobic lubrication layer with an appropriate pressure is formed.

On the other hand, no air layer is formed between the fixed cylinder 3 and the tape 250, and the tape 25 slides on the circumferential surface of the fixed cylinder 30. Therefore, the air layer formed between the rotating cylinder 2 and the tape 25 tries to flow into the gap between both cylinders and into the fixed cylinder 3 side, but the wall 19 prevents the air from flowing into the gap between the two cylinders. The pressure is increased, and as a result, the tape 25 is floated away from the rotating cylinder device 1.

FIG. 6 is a sectional view of a main part showing a floating state of the tape 25 in another embodiment of the present invention. In this embodiment, a wall 26 is further provided on the outer periphery of the rotary cylinder 2. As a result, the space formed by the rotating cylinder 2, the fixed cylinder 3, and the wall 26 becomes smaller, and the air pressure in the gap between both cylinders can be increased.
can be levitated. However, since the wall 26 is provided on the outer periphery, the grooves 23a and 2Ft3 are also closer to the outer periphery, and the wall thickness of this portion relative to the outer periphery of the rotary cylinder 2 becomes thinner. Therefore, it is necessary to ensure that the outer peripheral surface of the rotary cylinder 2 has a wall thickness sufficient to maintain the required machining accuracy.

〔Effect of the invention〕

As described above, according to the present invention, since the tape around the rotating cylinder can be held stably and smoothly, damage caused by the tape contacting the rotating cylinder and tape imaging due to rotation of the rotating cylinder can be suppressed, and the tape can be stably and smoothly held. Playback images can be secured. Moreover, since the structure is simple, economic efficiency is not sacrificed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotating cylinder showing an embodiment of the present invention, FIG. 2 is a perspective view showing a traveling system around the rotating cylinder,
FIG. 3 is a perspective view of the rotating cylinder, FIG. 4 is a perspective view of the upper rotating cylinder, FIG. 5 is a partial sectional view showing the state of the tape wound around the rotating cylinder device, and FIG. 6 is a perspective view of the rotating cylinder device. FIG. 2 is a cross-sectional view of a main part of a cylinder showing an embodiment of the invention. 1... Rotating cylinder device 2... Rotating upper cylinder 6
...Fixed lower cylinder 5...Window 6...Magnetic head 7...Shaft 11...Disk 19...
・Wall 21...Head base 25...Tape 26
...Wall 23...The head is installed in the groove.

Claims (1)

[Claims] A magnetic tape is spirally wound over a predetermined angular range around a rotating cylinder device consisting of a rotating cylinder equipped with a magnetic head and a fixed cylinder facing the rotating surface of the rotating cylinder, and signals are recorded by the magnetic head. - In a magnetic recording/reproducing device that performs reproduction, a wall is protruded from the rotating surface of the rotating cylinder over almost the entire circumference in the direction of the rotating axis inside the outer circumferential surface of the rotating cylinder, and is disposed close to the fixed cylinder. A rotating cylinder device featuring: