JPS61242361A - Rotary magnetic head device - Google Patents

Abstract

PURPOSE:To improve the tape contact and to omit the use of another vent path by discharging forcibly an air film produced between a rotary drum and a magnetic tape existing near an upper magnetic head through a vent path formed in a rotary drum by means of a suction fan. CONSTITUTION:When a rotary drum 11 and a saction fan 30 are revolved toward B in one body, the negative pressure is produced at a cavity part 33 of the fan 30 by the centrifugal force. An air film 8 is produced between the drum 11 and a magnetic tape 6 having a contact with the drum 11 and a fixed drum 12. The film 8 is sucked by a sucking port 33 of the fan 30 through a window 23 formed at the outer circumference of the drum 11 and a groove 19 formed on the upper surface side of the drum 11. Then the film 8 is discharged toward an arrow head C by plural sheets of vanes 34 and the fan 30. Thus the film 8 is greatly reduced at the outer circumference of the drum 11 and the tape 6 is never floated up by the excessive film 8 and approaches to the outer circumference of the drum 11. This improves the contact between the tape 6 and a head chip 1a of an upper rotary magnetic head 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rotating magnetic head device, and particularly to a rotating magnetic head device having a structure in which two-phase rotating magnetic heads are provided at different heights above and below in the axial direction of a rotating drum. The present invention relates to a rotating magnetic head device.

(Prior art) The present applicant previously submitted a patent application filed on February 25, 1985.
No. 0-35827 and Japanese Patent Application No. 60-35828 (title of the invention ``Color Video Shintan Recording and Reproducing Apparatus'') were proposed.

FIG. 3 shows a track pattern formed on the magnetic tape-L by this recording/reproducing apparatus (VTR). This is the lower recording band a1 that divides the bottom of the magnetic tape into two in the width direction.
ffI degree signal tracks Y+ and Y2 are alternately recorded on the upper recording band a2, and color signal tracks C1 and C2 are alternately recorded on the upper recording band a2. In a recording and reproducing apparatus (VTR) that uses such a signal recording and reproducing method, the luminance signal and the color signal are divided into recording bands al and a2 on the upper and lower sides of the magnetic tape T, respectively, and the luminance signal and the chrominance signal are azimuthal in a guard panless manner. Since the tracks are recorded, the recording density is high, and since there is a field correlation between adjacent tracks, crosstalk is less noticeable on the screen.

In addition, in FIG. 3, tracks A+, A2°B, and C formed along the longitudinal direction of the magnetic tape T are tracks recorded and formed by a dedicated fixed head.
A2 is the first. B is the audio track where the audio signal of the second channel is recorded, B is the time code track where the time code for knowing the position information on the tape is recorded, and C is the control track where the control pulse of a certain period is recorded. .

FIG. 4 is a schematic side view of a rotary magnetic head device applied to such a recording/reproducing apparatus.

In the figure, the upper rotating magnetic head 1C (for color signals) and the lower rotating magnetic head 2 (for brightness m) are aligned in the axial direction of the rotating drum 3 with a step equal to the distance 1h in FIG. It is installed on the same line (inline) above and below.

Note that the rotary drum 3 is coaxially mounted with the fixed drum 4 below it, and a tape guide (lead) 5 is integrally formed on the outer circumference of the fixed drum 4. 6 (indicated by a two-dot chain line) is attached to the rotating drum 3 and the fixed drum 4 and guided to run diagonally.

Further, the rotating drum 3 is rotationally driven by a drum shaft 7 supported below the fixed drum 4.

(Problems to be Solved by R-Mei) A rotating drum-type rotating magnetic head device includes a rotating drum 3 and a fixed drum 4 to which rotating magnetic heads 1 and 2 are attached. , rotating magnetic head 1,
Let the helad tip of No. 2 protrude slightly to the outside of the drum,
Both drums are brought into contact with a magnetic tape 6 wound diagonally.

However, due to this configuration, as is well known, an air film is generated between (the surroundings of) the rotating drum 3 and the magnetic tape due to the high speed rotation of the drum and the effect of the protruding head chip.

This air film has the effect of slightly floating the magnetic tape above the periphery of the rotating drum 3 and reducing the rotational loss of the rotating drum 3, but if it is produced in excess, it has a negative effect on the tape contact of the rotating magnetic head. effect.

On the other hand, the amount of air film generated between the magnetic tape and the stationary fixed drum 4 is smaller than that around the rotating drum 3.

By the way, since the magnetic tape is wound diagonally across both drums, when the rotating magnetic head enters the magnetic tape from the fixed drum 4 side, the rotating magnetic head enters the magnetic tape from the fixed drum 4 side with a small amount of air film. The magnetic tape on the drum 4 side can be pushed away.

This causes disturbances to be applied to the magnetic tape,
The tape contact of the following rotating magnetic head becomes unstable.

That is, as seen in FIG. 5, since the upper rotating magnetic head 1 is located approximately in the middle of the rotating drum 3, the magnetic tape 6 in this portion is floating due to the excess air film 8.

On the other hand, the magnetic tape 6 near the rotating magnetic head 2 on the lower side near the fixed drum 4 has a small amount of air film between it and the fixed drum 4, so that the magnetic tape 6 in that area is not in contact with the fixed drum 4. Therefore, the lower rotary magnetic head 2 enters first, causing disturbance to the magnetic tape 6, and the upper rotary magnetic head 1, which enters later, receives both the disturbance of the magnetic tape 6 and the levitation caused by the air film. Tape contact becomes even worse due to the influence of

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned problems of the conventional technology, and the air film generated between the rotating drum and the magnetic tape and the disturbance applied to the magnetic tape cause the upper rotating magnetic head to hit the tape. An object of the present invention is to provide a rotating magnetic head device that prevents deterioration of the magnetic field.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a rotary drum 1
An air intake fan 30 is installed above the rotary drum 11, and an air passage is provided in the rotary drum 11 to communicate the window 23 for protruding the blade tip of the rotary magnetic head on the outer periphery of the rotary drum 11 with the intake port 33 of the suction fan 30. The present invention provides a rotary magnetic head device characterized by the following.

(Function) In the rotary magnetic head device having the above configuration, the upper rotary magnetic head can better contact the tape due to disturbances applied to the air film and the magnetic tape.

(Example) Next, an example of a rotating magnetic head device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a top view of an embodiment of a rotary magnetic head device according to the present invention, and FIG. 2 is a cross-sectional view taken along line AA' in FIG.

As shown in FIGS. 1 and 2, a rotating magnetic head device according to an embodiment of the present invention includes a rotating drum 11 and a fixed drum 12, and a bearing portion 13 is integrally provided below the fixed drum 12. A bearing 14a is formed in this bearing portion 13.
, 14b are fixed and support the drum shaft 15.

A flywheel 16 is fixed above the drum shaft 15, and the rotating drum 11 is fixed to the upper surface of the flywheel 16 by a mounting screw (not shown).

Further, two sets of rotary transformers 17 and 18 are arranged between the fixed drum 12 and the flywheel 1G, and transmit and receive brightness signals and color signals to and from the rotating magnetic heads 1 and 2, respectively.

An annular groove 19 is formed on the upper surface of the rotating drum 11, and the upper rotating magnetic head 1 is attached to the bottom surface 20 of this groove 19.
is attached to the lower surface 21 of the rotating drum 11.

(The above-mentioned groove portion 19 can be formed, for example, by lathe processing.) That is, the helad base 1b of the upper rotating magnetic head 1
is screwed into the bottom surface 20 of the groove portion 19 by two mounting screws 22A, and causes the head chip 1a to protrude from the window 23 on the outer periphery of the rotating drum 11.

Further, an adjustment screw 24 is screwed into the head base 1b of the upper rotating magnetic head 1, and the height of the head chip 1a is adjusted by turning the adjustment screw 24.

On the other hand, the head base 2b of the lower rotating magnetic head 2 is attached to the lower surface 21 of the rotating drum 11 with two mounting screws 22B, and the head chip 2a is inserted through a notch 25 in the lower edge of the outer periphery of the rotating drum 11. It stands out.

Further, the height of the head chip 2a is adjusted by turning an adjustment screw 26 screwed into the blade base 2b of the lower rotary magnetic head 2.

Note that another upper rotary magnetic head 27 and a lower rotary magnetic head 28 are provided at an angular interval of 180 degrees from the upper and lower rotary magnetic heads 1 and 2, but these rotary magnetic heads 27, 28 The installation method is exactly the same as that described above.

As shown in FIG. 5, when upper and lower rotating magnetic heads are mounted in-line on a rotating drum, disturbances and air films applied to the magnetic tape cause the upper rotating magnetic head to have poor contact with the tape.

Therefore, the rotary magnetic head device according to the embodiment of the present invention is provided with an intake fan 30.

This intake fan 30 is a flat centrifugal fan, and the upper plate 3
1 and the lower plate 32 form an annular intake port 33,
Furthermore, a plurality of sheets (for example, 16
A number of curved vanes 34 are arranged radially.

The intake fan 30 is a molded product made of, for example, Boria tar resin (trade name: Duracon), and the upper plate 31.
Lower plate 32. An inner wall 35 and a center portion 36 are also integrally formed outside the vane 34. The intake fan 30 is screwed onto the upper surface of the rotating drum 11 by, for example, three mounting screws 37, and the annular groove 19 on the upper surface of the rotating drum 11 and the annular intake air of the intake fan 30 are connected to each other. The opening 33 coincides with (communicates with) so that these are supplied and form a ventilation path as will be described later.

That is, as shown in FIG. 1, when the rotating drum 11 and the intake fan 30 rotate together in the direction of arrow B, negative pressure is generated in the cavity 33 of the intake fan 30 due to centrifugal force.

On the other hand, an air film 8 is formed between the magnetic tape 6 attached to the rotating drum 11 and the fixed drum 12 and the rotating drum 11.
is sucked into the intake port 33 of the intake fan 30 through the window 23 on the outer periphery of the rotary drum 11 and the groove 19 on the E side of the rotating drum 11, and is further discharged from the intake fan 30 in the direction of arrow C by a plurality of vanes 34. . As a result, the air film 8 on the outer periphery of the rotating drum 11 is significantly reduced, and the magnetic tape 6 is not floated on the rotating drum 11 by the excessive air film.
Since the head chip 1a of the upper rotary magnetic head 1 is close to the outer periphery of the magnetic head 1, the head chip 1a of the upper rotary magnetic head 1 makes good contact with the tape.

Further, in the rotating magnetic head device according to the embodiment of the present invention, an annular groove 19 is provided on the upper surface of the rotating drum 11.
1! An upper rotating magnetic head 1.27 and a lower rotating magnetic head 2.28 are attached to the bottom 1!1it20 of the section 19 and the lower surface 21 of the rotating drum 11, respectively, but these two surfaces are the same. Since lathe processing is carried out in the process, it is possible to increase the accuracy of parallelism on both sides, and furthermore, the upper rotating magnetic head 1.27 and the lower rotating magnetic head 2, 28 are attached at an angular interval of 180 degrees from each other. There is no difference in height between you and your comrades.

As described above, in the embodiment of the present invention, the rotation for attaching the upper rotating magnetic head 1°27 of the two sets of rotating magnetic heads installed at different heights in the upper and lower axial directions of the rotating drum 11 is described. An annular hole 19 on the upper surface of the drum 11 is connected to a window 23 on the outer circumference of the rotating drum to form an air film 8.
In addition, a centrifugal intake fan 30 is provided on the upper surface of the rotating drum 11 to forcibly exhaust the air in the groove 19. As a result, the upper rotating magnetic head 1 The air film 8 around the angle of .degree.27 can be effectively reduced, and especially the tape contact of the upper rotating magnetic head 1.21 can be made significantly better than that of the conventional one.

Note that the present invention is not limited to the above embodiments,
For example, the air passage communicating with the window 23 for protruding the head chip may be a recessed portion partially provided for mounting the upper rotating magnetic head 1 or 27 instead of the annular groove portion 19.

Further, the type of the intake fan 30 is not limited to the centrifugal type, and other types of suction means may be used.

Furthermore, the present invention is not limited to the above-mentioned color video signal recording/reproducing apparatus, but is also applicable to, for example, a helical scan type magnetic recording/reproducing apparatus disclosed in Utility Model Application Publication No. 170012/1983, in which an upper rotating magnetic head is used to record and reproduce images. Of course, it is also possible to record and reproduce audio signals using the lower rotary magnetic head.

Further, the arrangement of the pair of rotating magnetic heads is as follows.
Of course, the angle interval is not limited to degrees.

(Effects of the Invention) As described above, according to the rotating magnetic head device of the present invention, the air film generated between the magnetic tape near the upper rotating magnetic head and the rotating drum can be reduced by forming the air film inside the rotating drum. Since the air is forcibly discharged by an intake fan through a ventilation path, the tape contact of the upper rotating magnetic head, which previously had been particularly poor due to the air film and disturbances applied to the magnetic tape, has been greatly improved. In addition, since one set of upper rotating magnetic heads is attached to the annular groove formed on the rotating drum, this groove provides good tape contact with the air film near the upper rotating magnetic head. It has the advantage that it becomes a ventilation path and there is no need to provide a separate ventilation path.

[Brief explanation of the drawing]

FIG. 1 is a top view of an embodiment of a rotating magnetic head device according to the present invention, FIG. 2 is a cross-sectional view taken along the line 8--' in FIG. 1, and FIG. 3 is a plan previously proposed by the applicant. FIG. 4 is a schematic side view of a rotating magnetic head device applied to the previously proposed device, and FIG. FIG. 3 is a partial cross-sectional view showing how the magnetic tape is guided by the rotating magnetic head device. 1.27... Upper rotating magnetic head, 2.28...
Lower rotating magnetic head, 1a, 2a...head chip, 1b, 2b...head base, 6...magnetic tape, 8...air film, 11...
・Rotating drum, 12... Fixed drum, 13... Bearing part, 15... Drum shaft, 16... Flywheel,
19...Groove portion, 20...F surface of groove portion 19, 21...
・Bottom surface of rotating drum 11, 22△, 22B, 37...Mounting screw, 23...
・Window, 24, 26... Adjustment hole, 25... Notch, 3
0... Intake fan, 31... Upper plate, 32... Lower plate, 33... Intake port, 34... Vane (blade), 35
...inner wall, 37...center. 71 Bird

Claims (3)

[Claims] (1) In a rotating magnetic head device in which a plurality of sets of rotating magnetic heads are installed with steps above and below in the axial direction of a rotating drum, an intake fan is installed above the rotating drum, and the rotation of the outer periphery of the rotating drum is A rotating magnetic head device characterized in that an air passage is formed in the rotating drum to communicate a window for protruding a head chip of the magnetic head with an intake port of the intake fan. (2) The rotating drum has an annular groove formed on its upper surface, and the upper rotating magnetic head is attached to the bottom of the annular groove, and the annular groove is connected to the intake port of the intake fan. The rotary magnetic head according to claim 1, wherein the rotary magnetic head is coupled to form an air passage extending from a window for protruding a head chip of the upper rotary magnetic head on the outer periphery of the rotary drum to the intake fan. head device. (3) The rotating magnetic head according to claim 1, wherein the intake fan is a centrifugal intake fan having an intake port in the center and a plurality of vanes arranged radially outside the intake port. Device.