JPH06176454A - Rotary magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To stabilize a head touch around the detaching position of the head from a tape and to attain the high definition recording/reproducing operation. CONSTITUTION:The upper bottom face 8a of an opening part 8 for projecting the head of a rotary drum 2 is constituted so as to be inclined to the angle equal to the inclined angle of a lead 15 provided helically on a fixed drum 1 Also the side faces 8b, 8c of the opening part 8 are constituted so as to be formed to the tapered state broadening toward the side of a fixed drum 1 from the upper bottom face 8a of the opening part 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary magnetic recording / reproducing apparatus used in a VTR (video tape recorder), a DAT (digital audio tape recorder), etc., and more particularly to a head projecting opening formed on a rotary drum. The present invention relates to a rotary magnetic recording / reproducing apparatus in which the structure of a portion (head window) is modified to improve recording / reproducing characteristics.

[0002]

2. Description of the Related Art In a rotary magnetic recording / reproducing apparatus of this type, as is well known, the lower end of a magnetic tape (hereinafter referred to as "tape") is placed along a helical lead formed on a fixed drum, and the tape is attached to the lead. The drum device is wound around a predetermined angle. Then, a magnetic head (hereinafter referred to as a head) mounted on a rotary drum that is rotationally driven at a high speed is brought into relative sliding contact with a tape that is driven and driven at a constant speed to perform recording / reproduction. There is.

In such a rotary magnetic recording / reproducing apparatus, various measures for stably running the tape have been proposed. For example, in the prior art disclosed in Japanese Patent Laid-Open No. 60-119658, the tape is stabilized. For traveling, the lower part of the outer peripheral surface of the rotary drum is formed so as to extend to a position approaching the fixed drum. However, in the conventional rotary magnetic recording / reproducing apparatus of this type, the head protruding from the rotary drum is projected. The structure of the opening (head window) is generally simply a rectangular shape.

[0004]

In the prior art according to the above-mentioned prior application, the gap between the rotary drum and the fixed drum is made small so that the tape can be stably run.
There is no description about stabilizing the contact between the tape and the head in the vicinity of the position where the head is detached from the tape (so-called stabilization of the head touch). That is, in a conventional rotary magnetic recording / reproducing apparatus having a rectangular head protruding opening, the head touch performance near the position where the head is detached from the tape deteriorates for reasons described later, and in a VTR or the like, It was a factor that hinders high-quality recording / playback.

Therefore, the technical problem to be solved by the present invention is to solve the above-mentioned problems of the prior art. The purpose is to touch the head near the position where the head is detached from the tape. Is maintained, and therefore a rotary magnetic recording / reproducing apparatus capable of high-quality recording / reproducing is provided.

[0006]

In order to achieve the above-mentioned object, a rotary magnetic recording / reproducing apparatus according to the present invention is configured such that a part of the outer peripheral portion of the cylinder is cut out from the lower end of the outer peripheral portion of the cylinder of the rotating drum to the upper side. The upper bottom surface of the formed head protrusion opening (head window) is inclined at an angle substantially equal to the inclination angle of the tape guide lead formed on the outer peripheral portion of the fixed drum,
It was configured.

Further, the side surface of the opening provided in the rotary drum is formed in a taper shape which widens toward the fixed drum from the upper bottom surface of the opening.

[0008]

Since the tape runs along the lead formed in a helical shape on the fixed drum, the upper bottom surface of the opening for head projection provided on the rotary drum (the bottom surface facing the fixed drum in the opening) By inclining the tape to be equal to the inclination angle of the lead of the fixed drum, the gap between the upper end of the tape and the upper bottom surface of the opening has a constant width in the vicinity of the position where the head is detached from the tape, and the position where the head is detached from the tape is close. Also in the case, the surface pressure of the tape to the gap portion of the head can be made higher than before. Therefore, a stable head touch can be obtained even near the position where the head is detached from the tape.

Further, the side surface of the opening provided in the rotary drum is formed in a taper shape diverging toward the fixed drum side, so that the side surface of the opening is at a right angle to the lower end line of the rotary drum. In manufacturing, it is possible to reduce the occurrence of burrs at the side corners of the opening and prevent the tape from being scratched. Furthermore, since there are few burrs on the side corners of the opening, and the side corners of the opening can be gradually brought into contact with the tape depending on the taper angle of the side surface of the opening, impact resistance with the tape can be improved. Can be mitigated, and the impact on the tape when the opening enters or leaves the tape can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a front view of a rotary magnetic recording / reproducing apparatus (rotary magnetic head drum device) according to an embodiment of the present invention, and FIG.
FIG.

First, an outline of a rotary magnetic recording / reproducing apparatus (rotary magnetic head drum device) will be described with reference to FIG. Figure 2
In the above, 1 is a fixed drum and 2 is a rotating drum. A shaft 4 is rotatably supported on the fixed drum 1 via ball bearings 3, 3, and a disc 5 is fitted and fixed on the upper side of the shaft 4, and the rotary drum 2 is screwed to the disc 5. It is fixed by means such as a stop. Rotating drum 2
A head support plate 7 having a head (video magnetic head) 6 attached thereto is fixed by means of screws or the like, and the head 6 has an opening (head window) 8 formed in the cylindrical outer peripheral portion of the rotary drum 2. A predetermined amount (a minute amount) outwardly protruding from.

Reference numeral 9 denotes a rotary transformer stator portion adhered and fixed to the upper surface side of the fixed drum 1, and 10 denotes a rotary transformer rotor portion adhered and fixed to the lower surface side of the disk 5, and both 9 and 10 have a minute gap. Facing each other,
A known rotary transformer for transmitting and receiving signals between the head 6 and the recording / reproducing system circuit is configured. Further, 11 is a stator coil fixed to the lower side of the fixed drum 1 via a holding body 12, and 13 is a rotor magnet fixed to the lower side of the shaft 4 via a holding body 14.
1 and 13 are opposed to each other with a predetermined gap, and constitute a motor unit for rotationally driving the rotary drum 2.

In the above-mentioned structure, by selectively energizing and controlling the stator coil 11, the rotor magnet 13 and each member such as the rotary drum 2 which is integrated with the rotor magnet 13 rotate, and the rotary magnetic head drum device is provided with a predetermined value. Recording / reproduction of a video signal or the like is performed by relative sliding contact of the head 6 mounted on the rotary drum 2 with a tape wound and driven by a known tape traveling mechanism at an angle.

As shown in FIG. 1, a helical lead 15 is formed on the outer peripheral portion of the cylinder of the fixed drum 2 for stably guiding the tape, and the lower end of the tape is placed along the lead 15. It is designed to run. The rotary magnetic recording / reproducing apparatus of the present embodiment is, for example, for a VHS standard VTR, and the lead 15 is a VHS.
It is set to have an inclination angle θ defined by the standard. When the rotary magnetic recording / reproducing apparatus applied in the present invention is 8 mm video, DAT, or the like, the inclination angle θ of the lead 15 is set to a value determined by 8 mm video standard, DAT standard, or the like. Needless to say.

As shown in FIG. 1, the opening (head window) 8 formed in the rotary drum 2 cuts out a part of the cylinder outer peripheral portion from the lower end of the cylinder outer peripheral portion of the rotary drum 2 to the upper side. Is formed. In this embodiment, the upper bottom surface (bottom surface of the opening 8 facing the fixed drum 1) 8a of the opening 8 is made equal to the tilt angle θ of the lead 15 of the fixed drum 1 in accordance with the tilt angle θ. It is supposed to be tilted by an angle. In addition, the side surfaces 8b, 8c of the opening 8
Is formed in a taper shape that widens toward the fixed drum 1 side from the upper bottom surface 8a.

FIG. 3 is a perspective view showing a state in which the tape is wound around the rotary magnetic head drum device according to the present embodiment over a predetermined angle. In the figure, the tape 16 wound around the rotary magnetic head drum device at a predetermined angle is the lead 15 of the fixed drum 1 at the time of recording / reproducing.
Along the direction of the arrow A in the figure, and also the rotating drum 2
Rotates in the direction of arrow B in the figure. In addition, in FIG.
Reference numeral 17 is a guide pin for guiding the tape 16 along the lead 15. FIG. 3 shows a state in which the head 6 is about to be detached from the tape 16, and the head 6 is in contact with the upper end side of the tape 16 in the rotation phase of the rotary drum 2 shown in FIG.

The above is a schematic description of the configuration of the present embodiment. In order to further clarify the effect of the present invention, the operation of the conventional example and the operation and effect of the present embodiment will be described below while using the illustrated conventional example. Will be described in comparison.

FIG. 10 shows a state in which the rotary drum 2 having the rectangular opening 8'according to the prior art rotates in the direction of the arrow B, and the head 6 is about to be separated from the tape 16. As shown in the figure, the upper bottom surface 8a 'of the opening 8'according to the prior art is parallel to the lower end line of the rotary drum 2, and the side surfaces 8b', 8c 'of the opening 8'rotate. It is orthogonal to the lower end line of the drum 2. With the rotation of the rotary drum 2, the head 6 moves to the tape 1 in the order of (a) of FIG. 10 → (b) of FIG. → (c) of FIG.
6, but just before the head 6 is separated from the tape 16, as shown in FIG. 10C, the upper end of the tape 16 and the opening 8 ′ are the upper end of the tape 16, the upper bottom surface 8a ′, A triangular gap surrounded by the side surface 8c 'is formed. In FIG. 10, 6a is an operation gap of the head 6, which is a signal transmitting / receiving portion, and it is well known that the higher the surface pressure of the tape 16 applied to the operation gap 6a, the higher the output can be stably obtained. .

FIG. 11 is a view of the magnetization pattern recorded by the conventional configuration of FIG. 10 as seen from the diamagnetic surface of the tape 16. In FIG. 11, 18a, 19a and 18b are the magnetization patterns and the T _END 'part is The vicinity of the detachment of the head 6 is shown. The arrow C indicates the scanning direction of the head 6.

FIG. 12 shows a reproduction output waveform according to the above conventional example, in which the vertical axis represents the output level and the horizontal axis represents the time. As shown in FIG.
It can be seen that the reproduction output is reduced in the G portion of the reproduction output waveform from a, 19a, and 18b, that is, in the vicinity of the head detachment portion. In such a state, the lower part of the screen on the TV screen has a poor S / N ratio.

The cause of this is that when the head 6 is about to be separated from the tape 16, as shown in FIG. 10 (c), the upper end of the tape 16 and the opening 8'are in the tape 1
6 A triangular gap surrounded by the upper end, the upper bottom face 8a ', and the side face 8c' is formed, and the triangular gap allows the front side of the operating gap 6a (the front side when viewed in the head moving direction).
This is due to the peak of the surface pressure. Figure 13
The head surface pressure curve according to this conventional example is shown, in which the vertical axis represents the head surface pressure, and the horizontal axis represents the horizontal position of the head sliding surface.

The present invention has been made in order to solve the problems of the prior art as described above. Therefore, in this embodiment, the shape of the opening 8 for projecting the head is shown in FIG. It is set to a different shape. FIG. 4 shows a state in which the rotary drum 2 having the opening 8 according to the present embodiment rotates in the direction of arrow B and the head 6 is about to be separated from the tape 16. With the rotation of the rotary drum 2 in the direction of arrow B, (a) of FIG. 4 → (b) of FIG. → (c) of FIG.
Then, the head 6 separates from the tape 16, but the upper bottom surface 8a of the opening 8 is inclined at an angle equal to the inclination angle of the lead 15 of the fixed drum 1 as described above. Immediately before the head 6 is detached from, the gap between the upper end of the tape 16 and the upper bottom surface 8a of the opening 8 has a constant width as shown in FIG. 4 (c).

FIG. 5 is a view of the magnetization pattern recorded according to this embodiment as seen from the diamagnetic surface of the tape 16. In FIG. 5, 18a, 19a, and 18b are the same magnetization patterns as before, and the T _END portion is the same. Indicates a portion near the detachment of the head 6.

FIG. 6 shows a reproduction output waveform according to this embodiment, in which the vertical axis represents the output level and the horizontal axis represents the time. As shown in the figure, the magnetization patterns 18a, 19
It can be seen that the reproduction output is stably maintained at a high output even in the G portion of the reproduction output waveforms from a and 18b, that is, in the vicinity of the head detachment portion. This improvement effect is obtained by inclining the upper bottom surface 8a of the opening 8 to an angle equal to the inclination angle of the lead 15 so that the upper end of the tape 16 and the opening 16 are rotated in the rotation phase just before the head 6 is detached from the tape 16. 8
Even when the gap between the upper bottom surface 8a and the upper bottom surface 8a is constant, the surface pressure can be peaked at the working gap 6a portion of the head 6 even in the state of FIG. 4 (c). This is due to the fact that it can be made higher. Therefore, a stable head touch can be obtained even near the position where the head 6 is detached from the tape 16. FIG. 7 shows a surface pressure curve according to this embodiment, in which the vertical axis represents the head surface pressure and the horizontal axis represents the horizontal position of the head sliding surface.

Next, an example of a method of forming the opening (head window) 8 of this embodiment will be described with reference to FIG. FIG. 8 (a)
As shown in FIG. 2, the tip 20a is an end mill 20 having a truncated cone shape, and the rotation center axis L of the end mill 20 is L.
-L 'is inclined with respect to the rotation center axis line KK' of the rotating drum 2 by the lead inclination angle θ, and the lower end side of the cylindrical outer peripheral portion of the rotating drum 2 is cut to a predetermined depth, whereby the shape described above is obtained. The opening 8 can be formed. Here, the inclination angle ψ (ψ of the tip portion 20a of the end mill 20 with respect to the line MM ′ parallel to the rotation center axis line KK ′ of the rotary drum 2.
Is set to an appropriate value, so that the side surfaces 8b and 8c of the opening 8 are formed in a taper shape that widens toward the fixed drum 1 side from the upper bottom surface 8a of the opening 8 as described above. It is clear that you can do it.

FIG. 8B shows the opening 8 formed by the above-described processing method, and the upper bottom surface 8 of the opening 8 is shown.
a is equal to the inclination angle θ of the lead 15 of the fixed drum 1,
Further, the side surfaces 8b, 8c of the opening 8 have a tapered shape that widens toward the fixed drum 1 side. When the side surfaces 8b and 8c of the opening 8 are formed in a taper shape that spreads toward the fixed drum 1 side as in the present embodiment, the side surface of the opening is perpendicular to the lower end line of the rotary drum 2 ( The rotary drum 2 is larger than the conventional example shown in FIG.
It is possible to reduce the occurrence of burrs at the side corners of the opening 8 when finishing the outer peripheral surface of the tape, and to prevent the tape 16 from being scratched. Furthermore, depending on the fact that there are few burrs on the side surface corners of the opening 8 and the taper angles of the side surfaces 8b and 8c of the opening 8, the side surface corners of the opening 8 can be brought into contact with the tape 16 gradually. Therefore, the impact property with the tape 16 is mitigated, and the impact on the tape 16 when the opening 8 enters or leaves the tape 16 can be mitigated.

FIG. 9 is a diagram showing a method of forming the opening 8 of the rotary drum 2 according to another embodiment of the present invention. In this embodiment, as shown in FIG. 9A, an end mill 21 having a cylindrical tip is used, and the rotation center axis line LL ′ of the end mill 21 is the rotation center axis line K− of the rotary drum 2.
The rotary drum 2 is tilted with respect to K ′ by the lead tilt angle θ.
The lower end of the outer peripheral portion of the cylinder is cut to a predetermined depth to form the opening 8. FIG. 9 (a)
As shown in FIG. 9B, the opening 8 of this embodiment formed and formed by the end mill 21 of FIG.
Although a is equal to the inclination angle θ of the lead 15 of the fixed drum 1, the side surfaces 8b-1 and 8c-1 of the opening 8 are parallel to each other and are inclined by a predetermined angle θ with respect to the lower end line of the rotating drum 2. It becomes a thing. Also in this embodiment, since the upper bottom surface 8a of the opening 8 is equal to the inclination angle θ of the lead 15 of the fixed drum 1, the surface pressure in the vicinity of the head detaching portion can be made higher than before, and the tape 16 of the head 6 can be obtained. A stable head touch can be obtained even in the vicinity of the position where the head is separated from.

[0028]

As described above, according to the present invention, since the upper bottom surface of the head projection opening of the rotary drum is formed to be inclined at the same angle as the inclination angle of the lead of the fixed drum, the head is Near the position where the tape separates from the tape, the gap between the upper end of the tape and the upper bottom surface of the opening has a constant width, and even in the vicinity of the position where the head separates from the tape, the surface pressure of the tape against the head gap should be higher than before. Can be done. Therefore, it is possible to provide a rotary magnetic recording / reproducing apparatus capable of obtaining a stable head touch even near the position where the head is detached from the tape and enabling high-quality recording / reproducing.

Further, the side surface of the opening is formed in a taper shape diverging toward the fixed drum side, so that when finishing the outer peripheral surface of the rotary drum, the occurrence of burrs at the side corners of the opening is reduced. It is possible to prevent the tape from being scratched. Furthermore, depending on the fact that there are few burrs on the side corners of the opening and the taper angle of the side of the opening
Since the side corners of the opening can be gradually brought into contact with the tape, the impact resistance with the tape is mitigated, and the impact on the tape when the opening enters or leaves the tape is reduced. You can Therefore, it is possible to realize a rotary magnetic recording / reproducing apparatus which enables higher-quality recording / reproducing.

[Brief description of drawings]

FIG. 1 is a front view of a rotary magnetic recording / reproducing apparatus (rotary magnetic head drum device) according to an embodiment of the present invention.

FIG. 2 is a sectional side view of FIG.

FIG. 3 is a perspective view showing a state in which a tape is wound around a rotary magnetic recording / reproducing apparatus (rotary magnetic head drum device) according to an embodiment of the present invention over a predetermined angle.

FIG. 4 is an explanatory view showing a state in which the head is about to be separated from the tape in one embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a magnetization pattern on a tape recorded according to an example of the present invention.

FIG. 6 is an explanatory diagram showing a reproduction output waveform according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a head surface pressure curve according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram showing an example of a method of forming an opening of a rotary drum according to an embodiment of the present invention.

FIG. 9 is an explanatory view showing a method of forming an opening of a rotary drum according to another embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a state in which the head is about to be separated from the tape in the conventional example.

FIG. 11 is an explanatory diagram showing a magnetization pattern on a tape recorded by a conventional example.

FIG. 12 is an explanatory diagram showing a reproduction output waveform according to a conventional example.

FIG. 13 is an explanatory diagram showing a head surface pressure curve according to a conventional example.

[Explanation of symbols]

 1 Fixed Drum 2 Rotating Drum 6 Magnetic Head (Head) 6a Operating Gap 8 Opening (Head Window) 8a Upper Bottom of Opening 8b, 8c Side of Opening 15 Lead 16 Magnetic Tape (Tape) 20 End Mill

Continued Front Page (72) Inventor Toshihiko Imachi 1410 Inada, Katsuta City, Ibaraki Prefecture, Hitachi, Ltd. AV Equipment Division, Hitachi Ltd. (72) Inventor Kiyokazu Watanabe 1410, Inada, Katsuta City, Ibaraki Hitachi, Ltd. AV Equipment Division, Hitachi Ltd.

Claims (2)

[Claims] 1. A rotary drum having at least one magnetic head mounted thereon, an opening for projecting a predetermined amount of the magnetic head formed in the outer peripheral portion of the cylinder, and a helical lead for guiding a tape. In a rotary magnetic recording / reproducing apparatus having a fixed drum formed on an outer peripheral portion of a cylinder and holding the rotating drum so as to be rotatable, a rotary magnetic recording / reproducing apparatus comprising: A rotary magnetic recording / reproducing apparatus, wherein an upper bottom surface of the opening formed so as to be partially cut is inclined at an angle substantially equal to an inclination angle of the lead of the fixed drum. 2. The rotary magnetic recording / reproducing apparatus according to claim 1, wherein the side surface of the opening is formed in a taper shape that widens toward the fixed drum side from the upper bottom surface.