JPH0757353A - Cylinder device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a cylinder device capable of coping with a high frequency operation effectively by making the layer thickness of an air-film thin and uniform. CONSTITUTION:A rotary cylinder 2 formed by fixing plural numbers of magnetic heads 11 at prescribed-positions and a first fixed cylinder 1 in which a leading part guiding a magnetic tape 19 are arranged coaxially. A second fixed cylinder 10 is arranged coaxially with the rotary cylinder 2 on the opposite side of the first fixed cylinder 1 to an axial direction and a space of the second fixed cylinder 10 with the rotary cylinder 2 is set so as to be larger than the space of the first fixed cylinder 1 with the rotary cylinder 2. A notched part is provided at the side of the tape entrance of the magnetic tape 19 in the second fixed cylinder 10. The air-film is reduced by releasing air through the space and the notched part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder device of a magnetic recording / reproducing device such as a video tape recorder (hereinafter referred to as VTR).

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Publication No. 1-15929, for example, a cylinder device of a VTR is provided with a rotating upper cylinder having a plurality of magnetic heads and a lead portion for guiding the running of a magnetic tape. The fixed lower cylinder is coaxially arranged.

When the magnetic tape loaded in the cassette is pulled out from the cylinder device and wound around the cylinder device, and the magnetic tape is run along the lead portion of the lower cylinder, for example, Japanese Patent Laid-Open No. SHO 61-96 58-13935
As disclosed in Japanese Unexamined Patent Publication No. 7 and the like, an inclined guide and a flanged guide of a rotating roller are arranged at the tape entrance / exit of the cylinder device. Then, in order to make the magnetic tape pulled out from the parallel tape reel run obliquely with respect to the rotating cylinder by the tilt guide, the running surface of the magnetic tape is tilted, and the upper end of the magnetic tape is regulated by the flanged roller guide. Thus, the magnetic tape is configured to be guided by applying a constant force so as to travel along the lead portion.

[0004]

However, in the above-mentioned conventional device, a thin air layer called an air film is formed between the tape and the cylinder by the rotation of the rotary cylinder. This air film becomes thick especially on the tape entrance side, and adversely affects the recording / reproducing characteristics in an apparatus in which the gap between the magnetic head and the magnetic tape is not wide.
In recent years, there has been a tendency to increase the cylinder rotation speed due to the increase in recording density and the increase in frequency band due to digital recording. As a result, the air film becomes thicker and the magnetic tape and the magnetic head due to the increase in frequency. The important problem is that the space loss between them increases.

Further, in the tape guide at the entrance and exit of the cylinder device, particularly in the height regulating guide with the flange, the structure is more complicated than before, and the verticality of the flange,
The inclination was a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cylinder device of a magnetic recording / apparatus which can make the layer thickness of an air film thin and uniform and can effectively cope with high frequency.

[0007]

A cylinder device for magnetic recording / apparatus according to the present invention comprises a rotary cylinder having a plurality of magnetic heads fixed at predetermined positions, and a lead portion for guiding a magnetic tape. The first fixed cylinder is coaxially arranged, and the second fixed cylinder is coaxially arranged on the side opposite to the first fixed cylinder in the axial direction with respect to the rotary cylinder. The gap between the second fixed cylinders is set to be larger than the gap between the first fixed cylinder and the rotary cylinder, and a notch is formed on the tape inlet side of the magnetic tape of the second fixed cylinder. Parts are provided.

[0008]

According to the present invention, by narrowing the width of the rotary cylinder forming the air film, the amount (thickness) of the air film can be first reduced in this respect. A second fixed cylinder (fixed / upper cylinder) for guiding the magnetic tape is arranged on the upper side of the rotary cylinder. By increasing the clearance between the second fixed cylinder and the rotary cylinder, Air can be efficiently escaped from the gap, reducing the air film on the tape inlet side. Further, air can also escape from the cutout portion provided on the tape inlet side, thereby reducing the air film.

Further, by providing a tape regulation portion for the second fixed cylinder and adjusting the height thereof, the tape regulation can be performed in the cylinder device itself. As a result, the tape height adjustment by the guide provided separately from the conventional cylinder device can be eliminated, and the tape guide system can be simplified.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the cylinder device of the magnetic recording / reproducing apparatus of the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view of a cylinder device according to a first embodiment of the present invention. In the figure, reference numeral 1 is a fixed / lower cylinder (first fixed cylinder), and a shaft 3 serving as a central axis thereof is press-fitted and fixed. Reference numeral 2 denotes a rotating / upper cylinder, and a plurality of magnetic heads 11 are screwed and fixed at predetermined positions via a base material 12. A transformer base 6 is supported on the shaft 3 by bearings 4 and 5, and the rotating / upper cylinder 2 is screwed and fixed to the transformer base 6. Further, 7 and 8 are rotary and fixed rotary transformers, respectively, which are connected to a video signal processing circuit (not shown) via a terminal 18. Also terminal 1
A signal flows between the rotary transformer 7 and the magnetic head 11 via the switch 3.

At the upper part of the rotating / upper cylinder 2,
Fixed coaxially with this ・ Upper cylinder (second fixed cylinder)
10 is arranged, as shown in FIG. 2, in the tape advancing direction of the magnetic tape 19 (arrow A), specifically, on the tape inlet side (see FIG. 3) of the cylinder device,
When the clearance between the upper cylinder 2 and the fixed / lower cylinder 1 is l _1, and the clearance between the fixed / upper cylinder 10 is l ₂ , l _{1 is 30} to 50 μm or less, and l ₂ is 0.1 or less.
mm or more. Further, a notch 20 is arranged on the tape inlet side of the fixed / upper cylinder 10. Further, on the tape inlet side of the fixed / upper cylinder 10, the fixed / upper cylinder 10 is provided with a restriction portion 10a for restricting the magnetic tape 19 at its upper end. And as described later,
The upper cylinder 10 is configured to be vertically movable on its outer peripheral surface.

Further, in FIG. 1, the fixed / upper cylinder 10
In the mounting portion of the above to the motor pedestal 9, a clearance x is set on the lower surface of the fixed / upper cylinder 10 with respect to the screw 22 provided on the tape inlet side of the magnetic tape 19. Further, such a gap is not set for the screw 21 on the opposite side of the screw 22, and the stator 16 and the stator 16 are closely attached and attached. By providing the gap x, the fixed / upper cylinder 10 is deformed according to the tightening of the screw 22,
This allows the outer peripheral surface of the fixed / upper cylinder 10 to move up and down.

The fixed / upper cylinder 10, the rotating / upper cylinder 2 and the fixed / lower cylinder 1 are arranged so that the magnetic tape 19 is wound around them and runs. The rotation / upper cylinder 2 is driven by a rotor yoke 14 attached to the rotation / upper cylinder 2, a flat drive magnet 15 magnetized in multiple poles, and a motor mount 9 fixed on the shaft 3. Mounted stator yoke 16 and drive coil 17
The brushless motor is composed of

In the cylinder device according to the first embodiment, the magnetic tape 19 shown by the dotted line in FIG. 2 runs in the direction of arrow A and runs along the lead portion 1a formed on the fixed / lower cylinder 1. To do. The rotating / upper cylinder 2
The magnetic tape 19 rotates in the same direction as the running direction.
Since the magnetic tape 19 runs obliquely around the cylinder device, it runs along the cylinder in the range from the tape inlet side of the fixed / upper cylinder 10 to the vicinity of the central portion (see FIG. 3). Here, as shown in FIG. 2, the inter-clearance of the rotation-upper cylinder 2 and the fixed-bottom cylinder 1 and l _1, also between liked the fixed-upper cylinder 10 when the l _2, l ₂ Set the gap between them so that> l ₁ .

As described above, the cylinder device as a whole is divided into three parts of the fixed / lower cylinder 1, the rotary / upper cylinder 2, the fixed / upper cylinder 10, and the clearance l ₁ between the fixed / lower cylinder 1 and the rotary / upper cylinder 2 is set. Is set to be narrow, and a large clearance l ₂ between the fixed / upper cylinder 10 and the rotating / upper cylinder 2 is set. Further, a cutout portion 20 is provided in the fixed / upper cylinder 10 on the tape inlet side of the cylinder. In this way, fixed / upper cylinder 10 and rotating / upper cylinder 2
By providing the gap l ₂ and the cutout portion 20,
Air can be made to escape largely through these. As a result, as shown in FIG. 4, particularly on the tape entrance side where the thickness of the air film layer is a problem,
The thickness of the air film can be made significantly thinner than in the conventional case (dotted line).

As shown by the solid line in FIG. 4, the thickness of the air film could be made uniform from the tape inlet side to the tape outlet side. Therefore, the thickness of the air film layer can be made almost uniform from the tape entrance side to the center, and a cylinder device with less space loss can be realized even when the frequency of the recording signal is increased for digital recording or high density recording. be able to.

Further, in the first embodiment, the fixing / upper cylinder 10 is provided with the regulating portion 10a for guiding the tape running of the magnetic tape 19 from the upper end thereof so that it can be adjusted in the vertical direction. Conventionally, the tape guide is regulated by the tilt guide separately arranged at a position distant from the cylinder device and the rotating roller with the upper and lower flanges, but in this respect, the tape traveling can be guided by the cylinder device itself, As a result, the regulating upper and lower flanges attached to the rotating roller are not required, and therefore the guide structure can be remarkably simplified.

Further, even in the case of the multi-pole of the cylinder device, the readjustment is not required, and the tape running adjustment can be performed in the cylinder device alone, and the rationalization in the production can be achieved. Further, conventionally, the magnetic tape wound around the cylinder is provided with the lead portion on the fixed / lower cylinder side, but in the present embodiment, the regulation portion 10a for regulating from the upper end of the magnetic tape 19 is provided as described above. As a result, the length of the lead portion 1a on the fixed / lower cylinder 1 side can be shortened. As a result, the processing conditions for the lead portion 1a, particularly the processing curve, becomes gentle, the processing speed remarkably increases, and the processing accuracy also improves.

Further, FIGS. 5 to 7 show a second embodiment of the cylinder device according to the present invention. 5 is a sectional view of the cylinder device according to the second embodiment, FIG. 6 is a side view, and FIG. 7 is a plan view. The same reference numerals are used for the members that are substantially the same as the members according to the first embodiment.

In FIG. 5, bearings 4 and 5 are fixed to the fixed / lower cylinder 1, and a rotary shaft 3'is also supported. The transformer base 6 is fixed to the rotating shaft 3 ', and the rotary transformers 7 and 8 transmit signals to and from the magnetic head 11. Reference numeral 24 is a connection wiring board to the signal processing circuit. For the rotating / upper cylinder 2,
A plurality of magnetic heads 11 are arranged at predetermined positions with screws, and the rotating / upper cylinder 2 is fitted on the rotating shaft 3 '. A motor unit for driving the rotating / upper cylinder 2 is arranged below the fixed / lower cylinder 1 which is screwed and fixed to the transformer base 6. This motor part
Stator 16, drive coil 17, rotor magnet 1
5, the rotor yoke 14, and is fixed to the rotating shaft 3'through a bush 23.

In the second embodiment, as shown in FIG. 6, the fixed / upper cylinder 10 is arranged above the rotary / upper cylinder 2 as in the case of the first embodiment. The upper cylinder 10 is formed integrally with the support column 10b, and is fixed to the lower cylinder 1 by screws on its side surface. A restricting portion 10a for restricting the magnetic tape 19 from its upper end and a notch portion 20 are formed in the same manner as in the first embodiment, and a groove 10c is provided at a position closer to the upper side than the vertical center of the column 10b. ing. Then, in this groove 10c, a screw portion is formed on the fixed / lower cylinder 1 side, while a large hole is formed on the fixed / upper cylinder 10 side so as to loosely fit the screw, and the screw 22 is , Is configured to be screwed with the above-mentioned screw portion formed on the fixed / lower cylinder 1 side.

In the case of this first embodiment, the screw 22
The width of the groove 10c is widened and narrowed according to the relaxation and tightening of the groove. For example, by tightening the screw 22, the groove 10
The width of c becomes narrower, and the fixed / upper cylinder 10 moves downward. Therefore, even in this case, the tape running of the magnetic tape 19 can be guided by the cylinder device itself, and the guide structure can be remarkably simplified.

[0024]

As described above, according to the present invention, the fixed / lower cylinder and the rotary / upper cylinder and the fixed / upper cylinder are divided into three parts. By providing a large cutout portion and providing a cutout portion in the fixed / upper cylinder, air can be largely released through these gaps and the cutout portion. This makes the thickness of the air film much thinner,
Further, it is possible to realize a cylinder device which is uniform and has a small space loss with respect to the increase in frequency of the recording signal.

Further, the fixed / upper cylinder is provided with a restricting portion for the magnetic tape so that the tape running can be guided by the cylinder device itself, whereby the guide structure can be remarkably simplified. Further, it is not necessary to readjust the multi-pole of the cylinder device, and it is possible to significantly rationalize the production. Further, there are advantages that the processing conditions for the lead portion whose length can be shortened are relaxed and the processing accuracy is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cylinder device according to a first embodiment of the present invention.

FIG. 2 is a side view of the cylinder device according to the first embodiment of the present invention.

FIG. 3 is a top view of the cylinder device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a change characteristic of the air film thickness in the cylinder device according to the first embodiment of the present invention in relation to a conventional example.

FIG. 5 is a vertical sectional view of a cylinder device according to a second embodiment of the present invention.

FIG. 6 is a side view of a cylinder device according to a second embodiment of the present invention.

FIG. 7 is a top view of a cylinder device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Fixed / Lower Cylinder 2 Rotation / Upper Cylinder 3 Shaft 3'Rotary Shaft 4,5 Bearing 6 Transformer Stand 7,8 Rotary Transformer 10 Fixed / Upper Cylinder 10a Regulation Part 11 Magnetic Head 12 Base Material 14 Rotor Yoke 15 Drive Magnet 16 Stator Yoke 17 Drive Coil 19 Magnetic Tape 20 Notch 21, 22 Screw 23 Bushing 24 Connection Wiring Board

Claims (2)

[Claims] 1. A rotary cylinder having a plurality of magnetic heads fixed at predetermined positions and a first fixed cylinder having a lead portion for guiding a magnetic tape are coaxially arranged. A second fixed cylinder is arranged coaxially on the side opposite to the first fixed cylinder in the axial direction with respect to the cylinder, and a gap between the second fixed cylinder and the rotary cylinder is arranged between the rotary cylinder and the first fixed cylinder. It is set so as to be larger than the gap between the first fixed cylinders, and a cutout portion is provided on the tape inlet side of the magnetic tape of the second fixed cylinder. Cylinder device. 2. A rotating cylinder having a plurality of magnetic heads fixed at predetermined positions and a first fixed cylinder having a lead portion for guiding a magnetic tape are coaxially arranged. A second fixed cylinder is arranged coaxially on the side opposite to the first fixed cylinder in the axial direction with respect to the cylinder, and the second fixed cylinder can be restricted from traveling from the upper end of the magnetic tape. A cylinder device of a magnetic recording / reproducing apparatus, characterized in that an adjusting means for restricting running of the magnetic tape is constituted by providing a portion and moving the second fixed cylinder in the axial direction.