JPS62200566A - Rotary head assembly - Google Patents

Abstract

PURPOSE:To keep a contacting state between a recording medium and a head in a good condition, by changing a difference in level between an upper rotary cylinder and a lower fixed cylinder corresponding to the thickness of an air film generated between the upper rotary cylinder and a tape shaped recording medium. CONSTITUTION:An upper rotary cylinder 11 is formed in a circular shape, and the diameter of a lower fixed cylinder 12 is made larger by a share equivalent to the thickness of an air film F generated between a magnetic tape 14 and the upper rotary cylinder 11 in the rotating time of the upper rotary cylinder 11 than that of the upper rotary cylinder 11. In other words, the thickness of the air film F is set larger by about 10mum at the entrance position (a) of the magnetic tape 14, and by about 2mum at the exit position (c), and by about 6mum at an intermediate position (b). The lower fixed cylinder 12 is made larger by the share equivalent to the thickness of the air film F generated between the upper rotary cylinder 12 and the magnetic tape 14 than the upper rotary cylinder 11, and is made larger by the share of the thickness reducing gradually in a range from about 10mum-2mum. Consequently, by producing the air film F in which the thickness is reduced gradually in such way, the difference of level between the upper rotary cylinder 11 and the lower fixed cylinder 12 can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a rotary head assembly in a recording or reproducing device.

[Conventional technology]

In a conventional rotary head assembly used in a VTR, etc., as shown in FIG. It was constant between (a)) and the exit position ((C) in the same figure).

(Problem to be Solved by the Invention) However, the contact area between the magnetic tape 3, which is wound diagonally around both cylinders 1. It is the largest in the same figure (
The air layer F gradually decreases from the intermediate position of B to the exit L1 position of FIG. For example, as shown in FIG.
It differs by approximately 2 μm at the exit location.

For this reason, if the diameter difference between the upper rotating cylinder 1 and the lower fixed cylinder 2 is constant as in the conventional rotating head assembly, the diameter of the upper rotating cylinder 1 is equal to the air film F.
The lower fixed cylinder 2 varies substantially in proportion to the thickness of
A step is formed between the two cylinders 1.2, and the magnetic tape 3 is deformed as shown in FIG. 4 and wound around both cylinders 1.2.

As a result, there was a problem in that stable and good contact between the magnetic tape 3 and the magnetic head could not be obtained.

The present invention has been made to solve these conventional problems, and it is an object of the present invention to provide a rotating head assembly that can provide a stable and good contact state between a tape-shaped recording medium and a head.

[Means for solving problems]

In the rotary head assembly according to the present invention, the height difference between the upper rotary cylinder and the lower fixed cylinder is changed depending on the thickness of the air film generated between the upper rotary cylinder and the tape-shaped recording medium.

(Function) In the rotary head assembly of the present invention, the level difference between the upper rotary cylinder and the lower fixed cylinder is changed according to the thickness of the air film generated between the upper rotary cylinder and the tape. Once the air film is formed between the media and the upper rotating cylinder, there is virtually no step between the upper rotating cylinder and the lower stationary cylinder. Therefore, the tape-shaped recording medium can be wound around both cylinders without being deformed, and can maintain stable and good contact with the head.

〔Example〕

1 to 3 are diagrams showing an embodiment of the present invention. Fig. 1 is a side view of the main part thereof, Fig. 2 is a plan view of Fig. 1, and Fig. 3 is an explanatory view of the operation.

In the figure, 11 is an upper rotating cylinder, 12 is a fixed cylinder, and both cylinders 11 and 12 are combined with a gap g provided therebetween. 13 is - upper rotating cylinder 1! to 1
The magnetic head 14, mounted with a phase angle of 80 degrees, is a magnetic tape wound obliquely around both cylinders 11 and 12 so as to straddle them.

The five-part rotary cylinder 11 has a circular planar shape. The diameter of the lower fixed cylinder 12 is the same as that of the rotary cylinder 11 of the above-mentioned part.
The diameter is larger than the diameter of the upper rotating cylinder 11 by an amount equivalent to the thickness of the air film F generated between the magnetic tape 14 and the lower rotating cylinder 11 during rotation. That is, referring to the thickness of the air film F exemplified above, as shown in FIG. The position is about 6 μm larger.

The lower fixed cylinder 12 is larger than the upper light cylinder 11 by an amount equivalent to the thickness of the air film F generated between the rotating cylinder 11 and the magnetic tape 14, and in the above example, from about 10 μm. It is larger by the thickness that gradually decreases in the range of 2 μm. Therefore, when the upper rotating cylinder rotates, there is a thickness between the magnetic tape 14 and the l: portion rotating cylinder 11. - Approximately 10 μm at recorder position a (Fig. 3 (
a)) When an air film F is formed that gradually decreases to approximately 6 μm at the intermediate position ((b) in the same figure) and approximately 2 μm ((C) in the same figure) at the exit position C, the upper rotating cylinder 11 and the lower fixed cylinder 12 There is virtually no step between the two.

As a result, the magnetic tape 14 is wound obliquely around one cylindrical surface, and can maintain stable and good contact with the magnetic head 14.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a rotating head assembly that can maintain stable and good contact between the tape-shaped recording medium and the head.

[Brief explanation of drawings]

FIG. 1 is a side view of the main parts of a rotating head assembly as an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a side view of the main parts for explaining the operation of the embodiment. , FIG. 4 is a side view of a main part for explaining the operation of a conventional rotary head assembly. 11...2H section rotating cylinder 12------Lower fixed cylinder 13---Magnetic head 14---Magnetic tape F---Air film research Example/) @ Part side view Figure 1 JI of the embodiment shown in Figure 1! Partial plan view (a) (b) (c) Figure 3

Claims (1)

[Claims] A rotary head assembly characterized in that a step difference between the upper rotary cylinder and the lower fixed cylinder is changed depending on the thickness of an air film generated between the upper rotary cylinder and the tape-shaped recording medium.