JPS5965964A - Rotary head device of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate the contact of a magnetic surface of a tape and an edge part of upper and lower drums, and to reduce the jitter of a reproducing picture due to longitudinal vibration, by providing a freely rotatable rotating body between the upper drum and the lower drum. CONSTITUTION:A rotating body 36 is provided between an upper drum 21 and a lower drum 33, has a tape press-contacting face projected slightly from a tape running guide face 34, and is freely rotatable by rotating force applied to the tape press-contacting face, irrespective of a rotation of the upper drum 21. When the upper drum 21 rotates and a magnetic tape 30 is in a shifting state, an air layer 21' is formed between the tape 30 and the upper drum 21, it floats up by several mum from the outside circumferential face of the upper drum. Also, as for contact of the magnetic face of the tape 30 and heads 19, 20, the tape 30 is projected to the outside since a magnetic tape contact face 28 of the head projects by scores of mum from an outside diameter D1 of the upper drum 21. Contact of the rotating body 36 and the magnetic tape 30 becomes a state of a contact guide since the rotating body 36 is freely rotatable. Also, the tape 30 runs in the helical shape in a state that the magnetic tape running guide face 34 of the lower drum 33 and the magnetic face are made to adhere closely to each other.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotary head device for a helical scanning magnetic recording/reproducing device (hereinafter referred to as a VTR) that records (reproduces) video signals, etc. on a magnetic tape. be.

[Conventional configuration and its problems]

Conventionally, the rotary head device of a VTR consists of a rotating drum to which a magnetic head is attached, and a fixed drum having a magnetic tape guide surface on the underside.The magnetic tape is guided to the outer peripheral surface of each drum, and A conventional magnetic tape is generally configured to record (reproduce) a desired video signal on a magnetic tape by rotating the magnetic tape.A conventional example will be described below with reference to the drawings.

FIG. 1 shows a VTR using a conventional rotary head device, in which a magnetic chip 762 wound around a supply reel 1 is pulled out, guides 3, 4, 5, a rotary guide 6, an erasing head 7, guide 8, rotating head device 9, guide 10,
A tape running path is formed in the order of the audio control head 11, guide 12, capstan 13, vinyl roller 14, and guide 15, and reaches the take-up reel J6.

When the VTR is in the recording (playback) state, the magnetic tape 2 is held between the capstan 13 and the pinch roller 14 is pressed. It is transported in the direction of arrow a, wound onto the take-up reel 16, and the tenon post 18, which is fixed to one end of the tenon 7-i farm 1, rotates in the direction of the arrow and comes into contact with the magnetic tape 2, thereby completing the tape running path. forms a part of the magnetic tape 2 and applies tension to the magnetic tape 2. Reference numerals 19 and 20 designate a rotating magnetic head which is rotatable in the direction of arrow C, and can record or reproduce a desired video signal onto the magnetic tape 2 when the VTR is in a recording or reproducing state. Next, the rotary head device 9 in the above conventional example
The configuration will be described with reference to FIG.

21 in Fig. 2 is the upper drum, which has a rotating magnetic head of 19°20
is attached to the bottom and rotates in the direction of arrow C when the VTR is in recording or playback mode. 22 is a rotating disk provided in the center of the upper drum 21, and a motor 2 is installed in the center.
The rotating shaft 23 is directly connected to a rotor No. 4 (not shown). 25 has a magnetic tape running guide surface 26 on its outer circumferential surface that slides and guides the magnetic tape 0 over almost the entire range of the magnetic tape wound around the device, and a magnetic tape running height position on the lower side. A fixed lower drum is fixed at a predetermined position on the VTR main body (not shown) by a fixed lower drum having a lead 27 that helically restricts.

Next, FIGS. 3 and 4 are diagrams showing the state of contact between a rotary head device according to a conventional example and a magnetic tape. diameter. On the other hand, it is possible to increase the outer diameter D1 of the upper drum 21 by several micrometers, and to make the contact surfaces 28 of the magnetic tapes 19 and 20 protrude several tens of micrometers from the outer diameter D1 of the upper drum 21. Common. In the rotary head device according to the conventional example described above, when the VTR is in the recording or reproducing state, the contact state of the magnetic tape 2 is between the outer peripheral surface of the upper drum 21 and the magnetic surface of the magnetic tape 2, as shown in FIG. Since the upper drum is rotating, air is drawn in in the rotation direction to form an air layer 21', so that the magnetic tape floats several μm above the outer peripheral surface of the upper drum. Because the magnetic surface of the magnetic tape 2 and the magnetic tape contact surface 28 of the magnetic head 19.20 are in contact with each other, the rotating magnetic head 19.2
0's near magnetic tape 02 deforms and protrudes outward,
On the lower side, the magnetic surface of the magnetic tape 2 and the magnetic tape running guide surface 26 of the lower drum 25 are in close contact with each other. As shown in FIG. 4, the rotating magnetic head 19°20,
In other parts, the magnetic surface of the magnetic tape 2 and the upper drum 21
The outer periphery lower edge 29 of . Therefore, the magnetic surface of the magnetic take 02 has the lower outer edge 29 of the upper drum 21.
Contact scratches are likely to occur due to the contact between the upper drum 21 and the wear of the lower outer edge 29 of the upper drum 21. This phenomenon occurs because the magnetic tape 2 is running when the VTR is in recording or reproducing mode, so the magnetic surface of the magnetic tee 7''2 shown in FIG. The magnetic tape 2 moves in a helical manner, and contact scratches on the magnetic surface of the magnetic tape 2 are not very noticeable.However, when the VTR is in a state where recording and playback are temporarily stopped, the magnetic tape 02 is in a stopped state and, for example, when the VTR is If the playback is paused, the playback still image is required to be maintained, and in order to stabilize the playback still image, tension is applied to the magnetic tape 2, and the magnetic tape 02 shown in FIG. 9 and 20. Therefore, when the VTR is in the playback pause state, the magnetic head o2 is kept in contact with the rotating magnetic heads r9 and r2o, as shown in FIG. The magnetic surface and the lower outer edge 29 of the upper drum 21
Because the magnetic tape 20 is stopped running, contact with the magnetic tape 20 occurs at the same portion of the magnetic tape 2, and not only does the number of mutual contact scratches increase, but also the number of contact scratches on the magnetic surface of the magnetic tape 2 progresses. For example, the magnetic surface of the magnetic tape 2 may peel off, making it impossible to record or reproduce that portion. And the tension applied to the magnetic tape is also VT
Peeling of the magnetic surface of the magnetic tape 2 and wear of the lower outer edge of the upper drum 21 caused by contact between the magnetic surface of the magnetic tape 2 and the lower outer edge 29 of the upper drum 21 when R is in the recording or playback pause state. Because it has the effect of further promoting
This would only damage the magnetic tape 02 and shorten the life of the VTR due to abrasion of the lower outer edge 29 of the -1 Ni drum 21.

Furthermore, in recent years, VTRs have become smaller, thinner, longer, and have higher recording density. Small size (e.g. 5 μm to 10 μm),
Thin magnetic tape (e.g. 5 μm to 10 μm) is used to increase the drum outer diameter of the rotating head device (e.g. 30+nm to 4 μm).
You are in a situation where recording or playback is being performed at

Therefore, the wavelength recorded or reproduced on the magnetic tape 0 is very small (for example, 0.2 μm to 0.5 μm), and the surface roughness of the magnetic surface of the magnetic tape 0 is also very small in order to reduce the reproduction speed R-song loss of the rotating magnetic head. It has become more detailed. In addition, in recent years, the magnetic layer of magnetic tape has been coated with a metal such as Co on the surface of the film base together with a binder, and Co + N
It is also common to heat and evaporate a magnetic material such as i and deposit it on the surface of the film base. In particular, the thickness of the magnetic layer of the latter magnetic tape is 01μ? n, and along with this, the surface roughness is also 0.005μm to 0.05μm? ? It has reached Z level.

If a thin magnetic tape as described above, which tends to have higher density recording, is used in a conventional rotary head device, the rotary head device and the magnetic tape will come into contact as shown in FIG. That is, thin magnetic tape (e.g. total thickness 5 μm to 10 μm)
30 has a smaller stiffness in the width direction than the conventional magnetic chi 70, so even when the VTR is in the recording or reproducing state, the upper drum 21 and the lower drum 25 are
It will fit into the gap 31 between the two.

As described above, there is an air layer 21 between the magnetic surface of the magnetic tape 30 and the outer peripheral surface of the upper drum 21 in a rotating state.
′ is formed, the position of the magnetic tape 30 wound on the outer peripheral surface of the upper drum 21 in the width direction (arrow d) tends to become unstable, and the lower drum Since the magnetic tape running guide surface 26 of the lower drum 25 and the magnetic surface of the magnetic tape 30 are in close contact with each other and the magnetic tape 30 is moving, the magnetic tape running guide surface 26 of the lower drum 25
The widthwise position of the magnetic tape 3o wound around the magnetic tape 3o is in a stable state. The thin magnetic tape F30, which has been trending toward high-density recording in recent years, has lower stiffness in the width direction than the conventional thick magnetic tape 2, and when the VTR is in the recording or playback state, the magnetic surface of the magnetic tape 30 A predetermined tension is added to the magnetic tape 3o to maintain contact with the magnetic tape contact surface 28 of the rotating magnetic head (FIG. 3) 19,20. Therefore, the magnetic tape 3o is
5, the magnetic tape 30 enters the gap 31 between the upper drum 21 and the lower drum 25 and becomes curved, as shown in the figure.

This phenomenon not only causes contact scratches due to contact between the lower outer edge 29 of the upper drum 21 and the magnetic surface of the magnetic tape 30, but also causes contact scratches between the upper outer edge 32 of the lower drum 25 and the magnetic surface of the magnetic tape 30. New contact scratches occur due to contact,
The number of contact scratches on the magnetic surface of the magnetic tape 3o increases. As a measure to prevent contact scratches caused by contact between the magnetic surface of these magnetic tapes and the lower outer edge 29 of the upper drum and the upper outer edge 32 of the lower drum, conventionally, the lower outer edge of the upper drum and the upper outer edge 32 of the lower drum have been The upper edge of the outer periphery has a corner-cut shape'=
1: or R-shape, or by reducing the gap (31 in Fig. 5) between the upper drum and the lower drum. However, if the lower outer edge of the upper drum and the upper outer edge of the lower drum are made into a rounded or rounded shape, not only will the number of parts processing steps for the upper drum and the lower drum increase; Machining of a rounded or rounded shape must be performed with high precision, and large variations in dimensions will reduce the compatibility of the VTR.

In order to reduce the gap between the upper drum and the lower drum, it is necessary to process and assemble the upper and lower drums with high precision. Dimensional accuracy due to machining of each part,
Considering surface wobbling, assembly dimensional accuracy of the upper and lower drums, surface wobbling, etc., the gap between the upper drum and the lower drum should be 0.
It is necessary to set it to about 0.05 mm to 0.01 mm. but,
When using a thin magnetic tape, which has been trending toward higher density in recent years, the stiffness of the magnetic tape in the width direction is small and the total thickness is about 5 μm to 10 μm, and as shown in FIG. 21 outer periphery lower edge 29
Even if the outer circumferential upper edge 32' of the magnetic tape 30 and the lower drum 25 are made into a corner-cut shape, and the gap 31' between the upper drum 21 and the lower drum 25 is set small (for example, 0.05 mm), the magnetic properties of the magnetic tape 30 The lower outer edge 29' of the upper drum 21 and the lower drum 2 each have a beveled surface.
It is not possible to completely prevent contact with the outer circumferential upper edge 32' of 5, and it is not possible to eliminate mutual contact scratches at this portion.

Furthermore, for the reasons described above, the magnetic tape magnetic surface, the outer peripheral lower edge portions 29', 29' of the upper drum 21, and the lower drum 25
By contacting the outer peripheral upper edge 32, 32' of
When a VTR is in a recording or playback state, the magnetic tape is subject to transport load fluctuations and vibrations. That is, the sixth
As shown in the figure, the contact between the upper outer edge 32' of the lower drum 25 and the magnetic surface of the magnetic tape 30 occurs in the width direction of the magnetic chip 7030 (arrow f) as the magnetic tape 30 is transported helically. As the magnetic tape 30 moves, the frictional resistance at the contact portion also changes due to reasons such as the curvature in the width direction of the magnetic tape 30 changing into a helical shape, causing a transfer load fluctuation on the magnetic tape.

In addition, the lower outer edge 29' of the upper drum 21 and the magnetic tape 03
Similarly, as the magnetic tape 30 is transported in a helical manner, the contact with the magnetic surface of the magnetic chip 7030 moves in the direction of the arrow f, and the magnetic chip 7030 is brought into contact with the magnetic surface due to the influence of the rotating upper drum 21. Produces vibration. For these reasons, the transfer load fluctuation of the magnetic tape 30 and the contact vibration with the upper drum cause an increase in the wow and flutter of the VTR, as shown by the broken line in FIG.

In other words, in FIG. 7, the solid line indicates a conventional rotary head device that uses a thick magnetic tape (for example, 20 μm to 30 μm), and connects the magnetic tape to the lower outer edge of the upper drum and the upper outer edge of the lower drum. Wow and flutter characteristics are observed when the contact is small, and no components of magnetic tape transfer load fluctuations of 10 Hz or less and components of contact vibration between the lower edge of the outer periphery of the rotating upper drum and the magnetic tape are particularly observed. .

However, the wow/7 rattle characteristics shown by the broken line occur when a thin magnetic tape 30 (for example, 5 μm to 10 μtn) is used, and the magnetic tape 30 is caused by contact between the upper outer edge 32' of the lower drum 25 and the magnetic tape 30. The tape transfer load fluctuation component increases at a low frequency of 1 OHZ or less (arrow p), and the contact vibration component between the lower outer edge 29' of the upper drum 21 and the magnetic tape 30 increases at 30 Hz (arrow q). There is.

Similarly, the knock characteristics shown in Fig. 8 are shown by arrows p' and q' when a thick magnetic tape is used, as shown by the solid line, and when a thin magnetic tape is used, as shown by the broken line. As shown in Fig. 7, not only the low frequency components increase due to the increase in wow and flutter, but also the
Knocking near z (arrow S) will increase. The increase in knocking indicated by the arrow S is due to the vibration caused by the contact between the rotating lower outer edge 29' of the upper drum 21 and the upper outer edge 32' of the lower drum 25 and the magnetic surface of the magnetic tape 30. is the longitudinal vibration component of the magnetic chip 7030 caused by this. The longitudinal vibration frequency fT of the magnetic tape is the tape running path length of the VTR, to1, the Young's modulus of the magnetic tape, E,
% mass of magnetic tape ρ. Then, it is shown by the following formula.

In this case, the length of the guide 7° running and the length to is the tape running path from the capstan 13 and pinch row 214 to the rotation guide 6, which forms the nodes of longitudinal vibration when the magnetic tape 2 is running in FIG. It is the length. Further, longitudinal vibration of the magnetic tape always occurs in a VTR, and if the frequency is in the range of 500 Hz to 5 kHz, it will be very noticeable in reproduced images. Therefore, as a measure to reduce the longitudinal vibration of the magnetic tape, the lower outer edge 29' of the rotating upper drum 21 and the upper outer edge 32' of the lower drum 25 are connected to the magnetic surface of the magnetic chip 7'30. Although the vibration of the magnetic tape 30 due to contact is reduced, the magnetic surface and the lower drum 25 in the running state of 0:30 are
Dynamic friction coefficient μ2 and static friction coefficient μ with respect to the magnetic tape running guide surface 26. Since the longitudinal vibration of the magnetic tape 30 is expressed by the relationship of equation (1), for example, the guide shown in FIG. A rotary guide or the like having a large mass is provided between the magnetic tape 1o and the audio control head II to form a node for longitudinal vibration of the magnetic tape 3o, and the length to of the running path of the tape 3o, where longitudinal vibration occurs, is shortened and A common method is to move the vibration frequency f to a high frequency range so as to make it less noticeable on a VTR playback screen. However, as mentioned above, the magnetic tape 30 is VT
With the trend toward smaller, thinner, longer recording times, and higher density recording, a magnetic layer of Ca + Ni, etc. is formed on the film base surface by vacuum deposition, etc., and the roughness of the magnetic surface is 0005μ.
When using a magnetic tape of approximately 0.05 m to 0.05 μm, the lower outer edge 29' of the rotating upper drum 21
and the upper outer edge 32' of the lower drum 25 and the magnetic chi! Not only does the vibration of the magnetic tape 30 increase due to contact with the magnetic surface of the magnetic tape 30, but also because the roughness of the magnetic surface of the magnetic tape 30 is very small. The dynamic friction coefficient μ2 and the static friction coefficient μ0 with the running guide surface increase, the running load of the magnetic tee 7030 and the stick re-ruff 0 vibration increase, and the longitudinal vibration of the magnetic tape 30 increases. Signal jitter has also increased.

In addition, as a measure to move the longitudinal vibration frequency f of the magnetic tape 30 to a high frequency range to make it less noticeable on the VTrL playback screen, for example, it is possible to Because it is necessary to rotate the magnetic tape 30 in contact with the magnetic tape 30, this goes against the trend of VTRs becoming smaller and thinner.
This has led to a decrease in VTR productivity due to reasons such as an increase in the number of assembly steps.

[Purpose of the invention]

The present invention eliminates the drawbacks of the conventional example, eliminates contact between the magnetic surface of the magnetic tape and the edges of the upper and lower drums, reduces knocks on the playback screen due to longitudinal vibration of the magnetic tape, and enables high-density recording. The present invention provides a device for rotating magnetic recording and reproducing devices that improves the quality of reproduced signals of VTRs, which is becoming increasingly popular.

(Structure of the Invention) In order to achieve the above object, in the present invention, the magnetic tape of the lower drum is fixed between the rotating soil drum and the fixed lower drum having a lead that regulates the running height position of the magnetic tape. A rotatable rotating body having a magnetic tape abutting surface slightly protruding from the tape running guide surface is provided.

(Explanation of Examples) Embodiments of the present invention will be described in detail below with reference to the drawings.

In the embodiment, parts having the same configuration as those in FIGS. 1 and 2 are designated by the same numbers and symbols, and their explanations will be omitted.

FIG. 9 shows an embodiment of the present invention, and 33
At the lower side of the outer peripheral surface, the magnetic tape is connected to a lead 35 that regulates the running height of the magnetic tape in a full helical shape within a range of at least 1/2 or more of the total winding angle of the magnetic tape wound around the rotary head device. A fixed lower drum having a magnetic tape running guide surface 34 for sliding guidance is fixed at a predetermined position on the VTR main body (not shown). 36 is upper drum 2
1 and the lower drum 33, the lower drum 33・D
A rotating body having a magnetic tape abutting surface slightly protruding from the magnetic tape running guide surface 34, held by an internal bearing, and applied to the magnetic tape abutting surface regardless of the rotation of the upper drum 21. It can be freely rotated by rotational force.

Next, FIG. 10 shows a cross section of the rotary head device, in which a ball bearing 37 is located at the center of the lower drum 33.
．． 38 are provided on the upper side and the lower side, respectively, so that the rotating shaft 23 can be rotatably supported.

The rotating disk 22 is integrally fixed to the lower end of the rotating shaft 23 by adhesive or the like, and a bearing 3' is attached to the lower end.
7.38, a bearing thrust pressing member 39 which exerts a thrust pressing force and minimizes the clearance of each ball rolling surface of the -mear ring is fixedly tightened with a screw 40. 41 is a magnet fixed to the lower part of the lower drum, and 42 is a rotor wound with a coil that can be energized so as to obtain the rotational force of the rotating shaft 23 on the outside thereof. 4
3 is a commutator of the rotor 42, and 44 is an internal tooth of a frequency generator, each of which is fastened to the lower end of the rotating Ga1l 23 by a screw 45. 46 is a brush that applies current to the rotor 42 via the commutator 43; 47 is the external tooth of a frequency generator; 23 is detected, and in addition to an external motor and a drive circuit (not shown), the rotation speed of the rotating disk 22 and the upper drum 21, which is fastened to the disk surface with screws 48 on the outside thereof, is adjusted to a predetermined value. Configured to control the value.

49 is a rotating magnetic head mounting member having a rotating magnetic head 19 or 20 fixed at its tip, and is attached to the upper drum 21 with a screw 50.
The tightening is fixed on the underside of.

A rotary transformer 51 is attached to the lower surface of the rotary disk 22 and transmits a desired signal to the rotary magnetic head 19 or 20, and a fixed transformer 52 is disposed at the center of the lower drum 33 facing the rotary transformer 51. 53 and 54 are bearings provided at the center of the rotating body 36 which has a magnetic tape contact surface on the outer periphery.The fixed transformer 52 presses the fixed transformer mounting member 55 to which the fixed transformer 52 is glued, and thrusts the inner ring of the bearing 53. By applying a pressing force, the ball rolling surface clearance of each bearing is set to the minimum.

Therefore, the eccentricity and surface wobbling of the magnetic tape abutting surface provided on the outer periphery of the rotating body 36 are minimized, and are O and OO1, respectively.
It has reached a feather size of about 0.002 mm. Also, the rotating body 36
The rotational torque of 0.01g-m to 0.02g--rust level, and the magnetic surface of the magnetic tape (described later) and the abutment surface of the rotating body 360 visceral tape come into contact, and as the magnetic tape 0 moves. The configuration is such that it rotates. 56 is the bottom surface of the lower drum 33;
It is fastened to a predetermined position on the VTR main body (not shown) with screws or the like. 57 connects the motor 24 to the bottom surface 56 of the lower drum 33.
Tighten is a screw to fix it.

Next, FIGS. 11 and 12 show the contact surface of the magnetic tape 0 of the rotating body 36, the upper drum 21, the rotating magnetic field, and the door 1 in this embodiment.
9 and 20. FIG. 3 is a detailed view showing the contact state between the lower drum 33 and the magnetic tape 30; for example, the diameter of the magnetic tape running guide surface 34 of the lower drum 33 is set to DO as in the conventional case;
OK, on the other hand, set the outer diameter D1 of the 9mm 21 to a few μm.
(0,002 mm to 0.0051 mm) and the outer diameter of the magnetic tape zero contact surface provided on the outer circumference of the rotating body 36 is set to the same dimension as the outer diameter D1 of the upper drum 21.

In the explanation of FIGS. 11 and 12, the magnetic chip 70 used has a total thickness of 5 μm to 10 μm, as described above, and has lower stiffness in the width direction than conventional magnetic tapes.
We used thin solid tape 030, which has a tendency to become denser.
Let's talk about 8-go.

In FIG. 11, the VTR is in a recording or playback state,
When the upper drum 21 is rotating and the magnetic tape 30 is in the transport state, an air layer 21' is formed between the magnetic tape 30 and the upper drum 21 as in the conventional case because the upper drum 21 is rotating.
is formed, floating several μm above the outer peripheral surface of the upper drum.

Also, the magnetic surface of the magnetic tape 30 and the rotating magnetic head 19.
The magnetic tape contact surface 28 of 20 is in contact with the magnetic head 19 .
20 magnetic tape contact surface 28 is on the outer diameter of the upper drum 21,
Since the magnetic chip 7030 protrudes several tens of micrometers from the tip, the magnetic chip 7030 protrudes outward and is deformed. The contact between the magnetic tape contact surface of the rotating body 36 provided below and the magnetic chip 7'30 is caused by the contact guide because the rotating body 36 is rotatable regardless of the rotation of the upper drum 21. Because the magnetic tape 030 is in the transporting state, it rotates approximately in the transporting direction. Further, below the magnetic tape 030, the magnetic tape 030 runs in a helical shape with the magnetic tape 0 running guide surface 34 of the lower drum 33 and the magnetic surface of the magnetic tape 030 in close contact with each other. As shown in FIG. 12, the rotating magnetic head 19.2
For the above-mentioned reason, an air layer 21' is formed between the magnetic tape 30 wound on the outer peripheral surface of the upper drum 21 and the magnetic surface of the upper drum 21, and the magnetic tape contact surface of the rotating body 36 and The state of contact between each of the magnetic tape running guide surfaces 34 of the lower drum 33 and the magnetic surface of the magnetic tape 30 is in a contact guided state as in FIG. 11.

Next, the outer diameter of the upper drum 21-1 in FIG. 13 is the air layer generated between the magnetic surface of the magnetic tape 030 and the outer peripheral surface of the upper drum 21 with respect to the outer diameter D1 of the upper drum 21 in FIG. gap number μm (e.g. 0.002++++n~0.003+
The contact state of the magnetic tape 030 when the outer diameter is set to D2 is shown. That is, the rotating body 36
The outer diameter of the upper drum 21-1 is set so that the deformation of the magnetic tape 30 above the magnetic tape contact surface is minimized.

Next, the contact movement between the rotating body 36 and the magnetic tape 30 in the magnetic tape 0 running state of the rotary head device according to this embodiment will be described with reference to FIG.

FIG. 14 shows the magnetic tape running and gusts before and after the rotary head device when the present invention is implemented in a conventional VTR.
When the TR is in the recording or reproducing state, the magnetic tape 30 indicated by the broken line is being transported in the direction of arrow a. and to rotation 2
1. The magnetic tape 30 on the supply reel side with respect to the apparatus regulates the height position of the lower end surface 30b of the magnetic tape 30 with the lower side part 6b of the rotation guide 6, and the upper side part of the guide 8. 8a regulates the height position of the upper end surface 30a of the magnetic tape 30. Therefore magnetic Qi! 30, the rotation of the magnetic tape '30 wound around the rotary head device is caused by the upward regulating force indicated by the arrow g at the id 6 and the downward regulating force indicated by the arrow g at the guide 8 acting together. A regulating force is generated that leads to the i direction. In addition, during rotation, the height position of the upper end surface 30a of the magnetic tape 3° is regulated by the upper esso part 10a of the guide O, and the lower part of the guide 12 is rotated. , the height position of the lower end surface 30b of the magnetic tape 3o is regulated by the groove 12b. Therefore, similarly to the above, the magnetic tape 030 is guided by the arrow J at the guide 1o.
The downward regulating force indicated by the arrow and the upward regulating force indicated by the arrow on the guide 12 act together to generate a regulating force that causes the magnetic tape 3o wound around the rotary head device to move in the direction of the arrow 1. are doing. As a result, the running height position of the magnetic tape 3° wound around the rotary head device is controlled by the regulating force generated by the rotating guides 6, 8, and 10°12 in the direction of arrow i, and the lower drum 33 is It will be pressed against the provided helical glue 35.

Next, the magnetic tape running in the rotary head device of the present invention is performed with the magnetic tape contact surface of the rotor 36 and the magnetic surface of the magnetic tape 30 in contact with each other, and the magnetic tape is wound on the magnetic tape contact surface of the rotor 36. As the rotating body 36 rotates, a force Fl is generated in the rotating magnetic tape in the rotating direction. That is, as shown in FIG. 15, when the magnetic tape 3o is in a running state, the magnetic tape 0/yon is indicated by To, and Fl occurs upward by an angle θ with respect to the direction of To. Here, θ indicates the oblique angle of the helical lead 1.'35, which is provided on the lower drum 33 of the magnetic tape 3o and determines the height position of the magnetic tape 3o, and leads the magnetic tape 3o. The force F2 that acts to make the object levitate from 35 is expressed by the following relational expression.

F2 = Fl sinθ
-(2) In the above equation, the value of Fl is 11 mm of the contact surface of the magnetic tape 0 of the one rotating body 36 shown in FIGS. The coefficient .mu.l varies significantly depending on the rotational load torque of each of the bearings 53 and 54 provided at the center of the rotating body 3G shown in FIG. 10, the tension of the magnetic tape 3o, etc.

Next, FIG. 16 shows the set values of 1 magnetic theno 0 of the rotating body 36 of the rotary head device of the present invention and the inclination angle θ of the reed 935, and the magnetic tape 30' described in FIG. 15. t shows the relationship with the force F2 that acts to levitate the magnetic tape 3o from the IJ-de 35. For example, if the diameter D1 of the contact surface of the magnetic tape 0 of the rotating body 36 is approximately 50wn, and the tape width of the magnetic tape 3o is approximately 7 mm. , the tension of the magnetic tape 30 is 15 g to 20 fl K, the inclination angle θ of the 'IJ-do 35 is
are set to approximately 5 degrees, and the width m of the magnetic tape contact surface of the rotating body 36 is ml = 0.7 mm 1 m2 = 1.4 +
A case will be described in which the value is changed to nm + m3 = 2.0 mm.

As is clear from FIG. 16, the force F2, which acts to levitate the magnetic tape 3° above the lead 35,
If the pB of the magnetic tape contact surface of 6 is set to ``', it will be approximately 0.4!!, and if it is set to m2, it will be approximately 1.
If set to '2, 9, m3, approximately 2.2.9 will occur, respectively. Therefore, in the case where the force m of the magnetic tape abutting surface of the rotating body 36 is set to m2, as shown in FIG. Therefore, in order to align the magnetic tape 30 along the lead 35 and stably regulate the running height position of the magnetic tape, it is sufficient that a force greater than F2 acts in the opposite direction to F2. As described in FIG. 14, the force that acts to make the magnetic chip 7630 follow the lead 35 against the force of F2 is the rotation guide 6, the guides 8, 1.
Arrow due to the action of the regulating force of the magnetic tape 3o generated at 0°12! This is the direction, that is, the pressing force that causes the magnetic tape 3o to follow the lead 35. As is clear from FIG. 14, this pressing force acting in the direction of arrow i is a magnetic force! 30
The lower drum 3 regulates the height position of the lower end surface 30b of the
If the tape path from the lead 35 to the guide 8 and the guide 8 to the rotating guide 6 and the tape path from the lead 35 to the guide 1o and from the guide 10 to the guide 12 are set small, a large force can be obtained. become. In this example, the length of these tape paths is 10 m.
Even when using a thin magnetic tape 3o, which tends to be more dense and has a total thickness of 5 μm to 10 μm, with a setting of about m-15 mm, a force of about 3 g will be generated to force the magnetic tape to follow the lead 35. .

Therefore, in Fig. 16, the width m of the contact surface of the rotating body 360
Even when set to m2, the magnetic chi 7'30t
Approximately 1.2g that acts to levitate from lJ-do 35
Rotating guide 6, guide 8, 10.12 for the force F2 of
Due to the action of the respective restraining forces of the magnetic tape 30'! f
- Since a force of about 3 g is generated to force the lead 35 to follow, the lead 35 is
The phenomenon of floating above 5 does not occur.

In addition to the above methods, methods for increasing the force acting to make the magnetic tape 30 follow the leads 35 (force in the direction of arrow i in FIG. 14) include methods for increasing the stiffness of the magnetic tape 30 in the forward direction, and A method of reducing the 7'300 width, a method of increasing the contact area with the magnetic tape end face at the magnetic tape end face regulating portion of the rotating guide 6, guide 8, 10.12, a method of reducing the tension applied to the magnetic tip f30. etc.

In the end, in this embodiment, when the magnetic tape 3o is in the running state, the magnetic tape 3o is transferred to the lead 35 of the lower drum 33.
The height position is regulated.

And the lower drum 33 and the upper drum 21-1 (or 21)
The contact between the magnetic tape contact surface of the rotating body 36 provided between the magnetic tape 3o and the magnetic tape 3o is made at an angle corresponding to the inclination angle θ of the lead 35.

Next, the force F2 that acts to levitate the above-mentioned magnetic chip f30 above the lead 35 and the lead 35 of the lower drum 33 are connected.
The inclination angle θ and the width m of the magnetic tape contact surface of the rotating body 36
The relationship between the two will be described with reference to FIG.

As is clear from FIG. 16, the inclination angle θ of the lead 35
If the value of θ is increased, the force F2 that acts to levitate the magnetic tape '30 above the lead 35 increases, and when the value of θ exceeds 106, F2 becomes extremely large. Furthermore, if the width m of the magnetic tape contact surface of the rotating body 36 is increased,
F2 also shows a tendency to become very large, and the magnetic chi 7°3o is made to align with the lead 35 due to the restraining force of the magnetic tape 30 generated by the rotating guide 6, guides 8, 10, and 12 described in FIG. Since the value of the pressing force is about 3 g, the value of F2 shown in FIG. 16 needs to be set to 3I or less.

Accordingly, from FIG. 16, it is sufficient to set the inclination angle θ of the lead 35 and :l@m of the magnetic tape abutting surface of the rotating body 36 within a range in which the value of F2 remains below 3 g. For example, when m is set to 1.4 mm compared to m2, the upper limit of θ is about 10°. Similarly, m is m 3 = 2
．． When set to Onrm, 0 may be set to about 6°. Next, the width m of the magnetic tape contacting surface of the rotating body 36 and the range of the lead 35 provided on the lower drum 33 according to this embodiment, that is, the width m relative to the total winding angle of the magnetic tape wound around the rotating head/device. The relationship with the winding angle α around the wire 35 will be described.

In this embodiment, the total winding angle of the magnetic tee f30 wound around the rotary head device is determined by the reason that the rotary magnetic head 19, 20 is arranged 180 degrees off the upper drum 2l-1 (or 21). The angle is set at about 190°. As is well known, in the conventional rotary head device, the wound magnetic tape has a helical shape, so the lead provided under the lower drum that regulates the running height of the magnetic tape is connected to the rotary magnetic head device. The winding angle was set at 190°, which is approximately the same as the total winding angle of the magnetic tape. In this embodiment, the total winding angle of the magnetic tape wound around the rotary head device is set to 190°, which is the same as in the conventional example, but the height position is regulated by the lead 35 provided on the lower drum 33. The winding angle α of the magnetic arm f30 changes depending on the set value of the width m of the magnetic tape abutting surface of the rotating body 36 and the set value of the inclination angle θ of the lead 35.

For example, the inclination angle θ of the lead 35 of the lower drum 33 is set to about 5
, the width m'xrr+ of the magnetic tape contact surface of the rotating body 36
When set to z2 and 1.4+nm, the winding angle α of the magnetic tape 30 whose height position is regulated by the lead 35 is
is approximately 125°, and when m is set to rrH = 0.7na, the winding angle α is approximately 160°; similarly, m is set to m3
"" When set to 2.0 mm, the wrapping angle α is approximately 9
Each is set to 0°.

When the direct line IIgm of the magnetic tape contacting surface of the rotating body 36 is increased, the force F2 acting to levitate the magnetic tape 30 above the lead 35 also increases, as described in FIG. 16. Therefore, when the inclination angle θ of the lead 35 is set to approximately 5°, the value of the width rn of the magnetic tape contact surface of the rotating body 36 is m3.
= It is necessary to set it to about 2.0 mm, and in this case, the magnetic tape 3o whose height position is regulated by the lead 35
The winding angle α is approximately 90°, and in the case of this embodiment, it is sufficient that the winding angle α is 90′ or more for the reasons described above.

Next, another embodiment will be described with reference to FIGS. 17 to 21, in which the shape of the magnetic tape contact surface of the rotating body 36 is changed to reduce the contact resistance with the magnetic surface of the magnetic tape 30. 17 and 18 show the magnetic tape abutting surface of the rotating body 36 (for example, a plurality of grooves each having a width of 0.1 mm and a depth of about 0.05 am are provided, and the magnetic tape abutting surface and the magnetic tape in a running state of the magnetic tape are provided). The contact area with the magnetic surface of 30 is made small, and the contact resistance is made smaller than that shown in FIGS. 12 to 14. Also, as shown in FIG. 19, a helical groove is provided on the magnetic tape contact surface of the rotating body 36, and as shown in FIG.
The contact area with the magnetic tape 30 is determined by a method of forming a groove perpendicular to the direction of rotation of the magnetic tape 30, and a method of pressing a spherical knurling on the magnetic tape contact surface and arranging hemispherical recesses as shown in FIG. It is also possible to make it smaller.

As a method for reducing contact resistance other than reducing the contact area of the magnetic tape contacting surface of the rotary body 36, there is the 11th method.
What is necessary is to reduce the coefficient of friction μ caused by the contact between the magnetic tape contacting surface of the rotating body 36 and the magnetic surface of the magnetic chip f30 in FIGS. In this method, S is placed on the magnetic tape contact surface.
It is also possible to deposit iC+ WCr T'+C+ etc. by means such as vapor deposition.

As described above in the embodiments, the present invention provides a rotating upper drum 21-1 (or 21) and a lower drum 3 having a lead 35 for regulating the running height position of the magnetic tape 30.
3, the magnetic tape running guide surface 34 of the lower drum 33
Rotating body 36 having a slightly more protruding magnetic tape contact surface
The magnetic surface of the magnetic tape 30 and the magnetic tape contact surface of the rotating body 36 are brought into contact with each other to form a helical shape on the magnetic tape 30.
Since the structure guides the magnetic tape 30, the longitudinal vibration of the magnetic tape 30 remains at a very small level.

That is, magnetic tape 030'f: Since there is no contact between the magnetic surface of the magnetic tape and the outer peripheral edges of the upper and lower drums, which is the cause of longitudinal vibration, vibration of magnetic tape 0 due to contact and running Load fluctuations can be completely prevented. Further, the guide 35 regulates the running height position of the magnetic tape 300 within a range of at least 1/2 or more of the total winding angle of the magnetic tape 30 wound around the rotating head device.
and a magnetic tape running guide surface 34 for slidingly guiding the magnetic tape 30, the contact area of the fa magnetic tape running guide surface with the magnetic tape 0 is smaller than in conventional rotary head devices. The tape running load and the accompanying fluctuations are also reduced. The magnetic surface of the magnetic tape 30 is guided in a helical manner in the width direction by the contact surface of the magnetic tape 0 of the rotary body 36, and is in full contact with the magnetic tape 30. Since this is carried out over the entire range, extremely stable tape running can be achieved.

Furthermore, since the rotating body 36 is configured to rotate as the magnetic chip f30 travels, 1. (A node of 1" eave Taeg longitudinal vibration is formed by this rotating body, and it is possible to bring the magnetic tape longitudinal vibration frequency fT to about 10 kFlz shown by arrow U in FIG. In addition, there is a trend toward higher density recording due to the plurality of grooves and four hemispherical parts shown in FIGS. 17 to 21 provided on the magnetic tape contact surface of the rotating body 36. Even in contact with a magnetic tape composed of a magnetic surface with small surface roughness, the contact area can be reduced, so that the +a air tether 0 does not levitate above the lead 35 due to the rotation of the rotor 36, and a stable magnetic field is maintained. Tape running is obtained.

Therefore, according to the present invention, the following effects can be obtained.

(Effects) 1) To reduce wow, flutter, and notter in the reproduced signal so as to completely prevent the vibration of the magnetic tape caused by the contact between the magnetic surface of the magnetic chip 70 and the outer peripheral portions of the upper and lower drums. I can do it.

2) Since a rotating body with a contact surface for the ia magnetic tape is integrally provided with the rotary head device to form nodes of longitudinal vibration of the magnetic tape, jitter on the playback screen is minimized and the VTR can be made smaller. can contribute to

3) Since the magnetic tape running guide surface and the lead that slidingly guide the magnetic tape have a range of at least 1/2 or more of the total winding angle of the magnetic tape wound around the rotary head device, it is difficult to use the conventional rotary head device. On the other hand, since the magnetic tape running load can be reduced, the magnetic tape drive torque can be reduced and power consumption can be reduced.

4) The contact area with the magnetic tape can be reduced by multiple helical grooves and hemispherical recesses provided on the contact surface of the magnetic tape of the rotating body. Since tape can be used, it can contribute to the promotion of high-density recording on VTRs.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a VTR using a conventional rotary head device, Fig. 2 is a perspective view of a directional rotary head device, and Figs. FIG. 5 is a diagram showing the contact state between the rotary head device and a thin magnetic tape, and FIG. 6 is a diagram showing the contact state between the rotary head device and a thin magnetic tape. Figure 7 shows the state of contact between the VTR device and the thin magnetic tape, and Figure 7 shows the wow and flutter of the same VTR. FIG. 8 is a diagram showing the jitter of the VTR, FIG. 9 is a perspective view of a rotary head device according to an embodiment of the present invention, and FIG. 10 is a sectional view of the rotary head device. 1
Figures 1 and 12 are diagrams showing the state of contact between the rotary head device and a thin magnetic tape, and Figure 13 is a diagram showing the state of contact between the rotary head device and a thin magnetic tape when the outer diameter of the upper drum of the rotary head device is reduced. Figure 14, which shows the state of contact with the tape, shows the running of the magnetic tape before and after the rotary head device, and Fig. 15, which is an explanatory diagram of the regulation of the height position of the magnetic tape running, shows the state of the magnetic tape running before and after the rotary head device. An explanatory diagram of the magnetic tape running height position regulating force, FIG. FIGS. 17 to 21 are diagrams showing the shape of the magnetic tape abutting surface of the rotating body and the state of contact with the tape in other embodiments of the rotating device, respectively. ■... Supply reel, 6... Rotation guide, 11... Audio control head, 13... Capstan, 14... Pinch roller, 16... Take-up reel,
19.20...Rotating magnetic head, 21, 21-1.
- Upper drum, 30... Thin magnetic tape, 33... Lower drum, 34... Yamaki tape running guide surface, 35... Lead, 36... Rotating body. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 38th = 415- Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Old figure 20 Figure 21

Claims (2)

[Claims] (1) In a rotary head device that has a rotary magnetic head capable of recording or reproducing information on a magnetic tape and includes an upper drum that rotates at a predetermined speed, the total winding angle of the magnetic tape wound around the rotary head device a fixed lower drum having a magnetic tape running guide surface that slidingly guides a reed and a magnetic tube that helically regulates the running height position of the magnetic tape within a range of at least 1/2 or more; the upper drum; and the fixed lower drum; A rotary head device for a magnetic recording and reproducing device, characterized in that a rotatable body having a magnetic tape contacting surface slightly protruding from the magnetic tape running guide surface of the fixed lower drum is provided between the fixed lower drum and the magnetic tape running guide surface of the fixed lower drum. (2) A rotary head device for a magnetic recording and reproducing apparatus according to claim (1), characterized in that a plurality of grooves or four hemispherical parts are provided on the magnetic tape contacting surface of the rotating body.