JPH0196855A - Helical scan magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the relative dislocation between heads without complicating the internal constitution of a cylinder by fitting one side of a width regulating tape guide to a fixed part through an electric machine converting element, impressing voltage to the element and displacing the element. CONSTITUTION:Between a fixed cylinder 4 to hold a rotating cylinder 2 and a base 6, a laminating piezoelectric element 5, in which the thin plate of a ring piezoelectric element is laminated, is arranged as a laminating type piezoelectric actuator, and to this laminating piezoelectric element 5, the voltage according to a tracking error signal is impressed. By displacing the fixed cylinder 4 and the rotating cylinder 2 supported by the cylinder 4 in the axial direction of a cylinder rotating shaft through the use of the cylinder rotating axial directional expansion of the element 5 generated by the impression, a tape 100 and a head 3 are displaced relatively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention is a helical scan magnetic recording/reproducing device (hereinafter referred to as a VTR) capable of so-called auto-tracking, in which a magnetic head scans along the curve of a tape pattern. It is related to.

[Conventional technology]

An example of a method for performing automatic tracking in a conventional helical scan VTR is a dynamic tracking method. In this dynamic tracking method, for example, as described in Japanese Patent Publication No. 60-32259, a magnetic head mounted inside a rotating magnetic head device (hereinafter referred to as a cylinder) is attached to the tip of a piezoelectric bimorph. Once installed, a voltage is applied to the piezoelectric bimorph according to the tracking error signal, and the bending of the piezoelectric bimorph at that time is used to displace the height of the magnetic head in the tracking direction to automatically perform tracking.

[Problem that the invention seeks to solve]

In the above dynamic tracking method,
Since the mass of the movable part is small, there is an advantage that a large displacement can be obtained.

However, when there are a plurality of magnetic heads, each of them must be driven independently, making the internal structure of the cylinder complex. Furthermore, the piezoelectric bimorph has instability such as hysteresis, and it is difficult to maintain the relative height between the magnetic hands. Furthermore, in recent years, the diameter of cylinders has become smaller and smaller; for example, in DAT (digital audio tape recorders), the diameter of the cylinder is 30 mm, and smaller models are being prototyped. As the diameter of the cylinder becomes smaller, it becomes difficult to install the piezoelectric bimorph due to dimensional limitations.Furthermore, it is necessary to supply electric power to the rotating part of the cylinder in which the piezoelectric bimorph is mounted, so it becomes difficult to install the piezoelectric bimorph. Expensive parts such as rings and brushes are required.

Therefore, an object of the present invention is to solve the problems of the prior art described above, to prevent the internal structure of the cylinder from becoming complicated even when the number of magnetic heads increases, and to prevent relative positional deviation between the magnetic heads. Furthermore, it is an object of the present invention to provide a helical scan VTR that does not require power supply to the rotating part and can perform auto-tracking without any problem even if the diameter of the cylinder becomes small.

[Means for solving problems]

In order to achieve the above object, the present invention rotates all parts of the cylinder that come into contact with the magnetic tape around a rotating shaft, and also rotates the cylinder and the width regulating tape disposed near the cylinder. One of the guides is fixed to a fixed part, the other is attached to the fixed part with an electromechanical conversion element interposed therebetween, and a voltage or current is supplied to the electromechanical conversion element to drive the electromechanical conversion element. By this, the cylinder or the width regulating tape guide, whichever is attached to the fixing part via the electromechanical transducer, is displaced relative to the fixing part in the axial direction, and the magnetic head and the magnetic It is designed to control the relative position with respect to the tape.

[Effect]

As described above, in the present invention, one of the cylinder or the width regulating tape guide arranged near the cylinder is attached to the fixed part with an electromechanical transducer, for example, a laminated piezoelectric element interposed therebetween, By applying a voltage to the laminated piezoelectric element, the resulting expansion and contraction of the laminated piezoelectric element is used to displace the cylinder or the width regulating tape guide in its axial direction, thereby changing the relative position between the magnetic head and the magnetic tape. change. At this time, in order to smoothly change the relative position between the magnetic head and the magnetic tape,
It is essential that the friction between the cylinder and the magnetic tape be small, but in the present invention, by rotating all parts of the cylinder that come into contact with the magnetic tape around a rotating shaft, the cylinder and the magnetic tape can be Since an air layer is formed between the two and the friction between the two is reduced, there is no problem.

Note that it is assumed that the voltage applied to the laminated piezoelectric element is a voltage corresponding to a solder tracking error signal detected by a well-known tracking error detection means.

As described above, according to the present invention, even if the number of magnetic heads increases, the internal structure of the cylinder does not become complicated.
Relative positional deviation between the magnetic heads can also be prevented, and moreover, so-called auto-tracking, in which the magnetic heads can be scanned along the curve of the tape pattern, can be performed without the need for power supply to the rotating section.

Moreover, as mentioned above, if cylinders become smaller in the future, the mass of the entire cylinder will also become smaller.
As mentioned above, an electromechanical transducer such as a laminated piezoelectric element makes it easier to move the entire cylinder in its axial direction at the required speed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing a cylinder and its surrounding parts in one embodiment of the present invention.

As shown in FIG. 1, a cylinder 1 is composed of a rotating cylinder 2, a fixed cylinder 4, etc. On the other hand, a magnetic tape (hereinafter simply referred to as tape) 100 is guided by tape guides 33 and 34 and spirals 180 degrees.
It is wrapped around the outer circumference of the rotating cylinder 2, and the rotating cylinder 2 rotates at high speed. A window 5 is provided on the outer periphery of the rotating cylinder 2.
0 is provided, from which a magnetic head (hereinafter simply referred to as head) 3 protrudes, contacts the tape 100, and scans it. Two heads 3 are provided at an interval of 180° and scan the tape 100 alternately.

Reference numeral 5 denotes an electromechanical transducer, and in this embodiment, a laminated piezoelectric element is used. That is, between the fixed cylinder 4 that holds the rotating cylinder 2 and the base 6, a laminated piezoelectric actuator 5, in which ring-shaped thin plates of piezoelectric elements are laminated in the direction of the cylinder's rotation axis, is arranged as a laminated piezoelectric actuator, and tracking is performed on this. Apply a voltage according to the error signal. Then, by utilizing the resulting expansion and contraction of the laminated piezoelectric element 5 in the direction of the cylinder rotation axis, the fixed cylinder 4 and the rotating cylinder 2 supported thereon are displaced in the direction of the cylinder rotation axis. to be relatively displaced.

That is, the base 6 is fixed to the cylinder base 7, and the cylinder base 7 is fixed to the chassis 8.

Further, each of the tape guides 33 and 34 is fixed to the cylinder base 7 by being crimped onto a catcher (not shown) fixed to the cylinder base 7.

Therefore, while the position of the tape guided by these tape guides 33 and 34 does not change, the rotary cylinder 2 is displaced in the direction of the cylinder rotation axis, and due to high speed rotation, there is sufficient space between the tape 100 and the rotary cylinder 2. Since a thick air layer is formed and the friction is low, relative movement between the head 3 and the tape 100 is possible.

In the above description, the tape guides 33 and 34 are described as movable tape guides that are pressed against the cancher, but these may of course be fixed guides that are fixed to the cylinder base 7. It may also be a width regulating tape guide that regulates the position.

Further, 9 is a rotary transformer stator, which is fixed by a support member 10 (not shown) fixed to the chassis 8 or the cylinder base 7, and is held coaxially with the cylinder rotation axis.

Next, the structure of the cylinder 1 will be explained in detail based on FIG.

FIG. 2 is a cross-sectional view showing the cross section of the cylinder l shown in FIG. 1, with the right half and left half representing cross sections at 90° with respect to the cylinder rotation axis 11, respectively.

As shown in FIG. 2, a disk 14 is fixed to the cylinder rotation shaft 11 by means such as press fitting, and the rotation cylinder 2 is attached to the disk 14 by a screw 26.
It has been stopped due to the anniversary.

A helad base 16 is attached to the mounting surface of the rotary cylinder 2 to the disk 14 with screws 25, and the head 3 is glued to the tip thereof, and protrudes from a window 50 made in the center of the rotary cylinder 2. There is.

A relay board 27 is fixed to the screw mounting surface of the rotary cylinder 2, and relays the connection between the head 3 and the low retrans rotor 12 fixed to the cylinder rotation shaft 11. The rotary transformer is a coaxial type rotary transformer, and the rotary transformer rotor 12 and the rotary transformer stator 9 are arranged with an appropriate gap of about several tens of μm in between, and transmit signals. Note that the rotary transformer stator 9 is supported by the support member 10 as described above.

On the other hand, the cylinder rotation shaft 11 is supported by the fixed cylinder 4 via a pole bearing 13.15. The ball bearing 13.15 has a metal fitting 21 and a set screw 22.
Preload is applied by

A magnet holder 23 is screwed onto the metal fitting 21 with a screw 29, and a motor rotor magnet 20 is adhered to the magnet holder 23.

Further, a stator holder 17 is attached to the fixed cylinder 4 with screws 24, and this stator holder 17 is attached to the stator coil 19 with a stator yoke 18 interposed therebetween.
This portion constitutes a brushless direct-coupled drive motor that is directly coupled to the cylinder rotating shaft 11.

Further, as described above, the fixed cylinder 4 is attached to the base 6 via the ring-shaped laminated piezoelectric element 5, and the laminated piezoelectric element 5 is attached to the fixed cylinder 4. It is glued to the base 6. Further, the base 6 is fixed to the cylinder base 7 by screws 28.

Here, as described above, when a voltage is applied to the laminated piezoelectric element 5, the laminated piezoelectric element 5 expands and contracts in the direction of the cylinder rotation axis, and thereby the entire cylinder 1 except the base 6 moves in the cylinder rotation axis direction. At this time, the low retrans rotor 1
Although the low retransmission stator 2 and the low retransmission stator 9 are displaced relative to each other, the amount of displacement is extremely small and does not have any effect on the signal transmission characteristics.

Next, another embodiment of the present invention will be described based on FIG.

FIG. 3 is a sectional view showing a part of the cross section of a cylinder in another embodiment of the present invention, and other parts not shown in this figure are the same as shown in FIG. 2.

In this embodiment, the fixed cylinder 4 is supported on the base 6 by an elastic ring 35 made of an elastic body (for example, rubber).

On the other hand, an iron pin 36 is fixed to the outer circumference of the fixed cylinder 4, and an iron yoke 38 is fixed to the base 6, and as shown in the figure, the center hole of this yoke 38 is fixed to the pin 3. is movable in the central axis direction.A coil 37 is wound around the outer periphery of the yoke 38, and this part constitutes a solenoid.Although only two locations are shown in the figure, This solenoid is arranged at three equal intervals in the circumferential direction.
There are more than 300 pieces arranged.

Therefore, by passing a current through this solenoid and controlling the current, the attraction force of the solenoid changes. This suction force deforms the elastic ring 35, and this deformation displaces the fixed cylinder 4 in the direction of the cylinder rotation axis, changing the relative position between the head 3 and the tape 100, as in the embodiment described above. .

Next, another embodiment of the present invention will be described based on FIG.

FIG. 4 is a perspective view showing the inlet side of a cylinder in another embodiment of the present invention. In addition, in this embodiment, the configuration on the outlet side of the cylinder is also exactly the same.

In this embodiment, the cylinder 1 is not displaced in the direction of the cylinder rotation axis, but the tape guides immediately before and after the cylinder 1 are displaced in the direction of the guide axis.

In FIG. 4, the fixed cylinder 4 is fixed to the cylinder base 7. On the other hand, a width regulating tape guide 30 is arranged on the entrance side of the cylinder 1, and a laminated piezoelectric element 32 is disposed on the entrance side of the cylinder 1.
It is attached to the cylinder base 7 via. 31
is a moving tape guide, which moves during tape loading and wraps the tape 100 around the cylinder 1 and the width regulating tape guide 30.

As in the case of the embodiment shown in FIG.
By applying a voltage according to the tracking error signal to 2, the laminated piezoelectric element 32 expands and contracts, and the width regulating tape guide 30 moves in the guide axis direction. In this way, by simultaneously moving the width regulating tape guides immediately before and after the cylinder 1 (not shown) in the same direction, the tape 100 is moved and the relative position with respect to the head 3 is changed to perform tracking. Can be done.

Next, the structure of the width regulating tape guide 30 will be explained in detail based on FIG. - FIG. 5 is a sectional view showing a cross section of the width regulating tape guide 30 of FIG. 4.

As shown in FIG. 5, the tape guide 30 includes a head portion 41, a guide portion 48. Brim portion 42. Threaded portion 43. It is composed of a shaft section 44 and a support section 46 that supports the shaft section. Further, the laminated piezoelectric element 32 has a ring shape, is inserted between the support portion 46 and the cylinder base 7, and is bonded thereto. The shaft portion is slidably fitted into a hole portion of the cylinder base 7 by a shaft portion 44 at its tip, and its central axis direction is determined.

On the other hand, the height of the guide part 48 that regulates the width of the tape 100 can be adjusted by rotating the shaft part, since the thread part 43 is screwed into the female thread part of the support part 46. That is, the shaft portion is rotated until the height of the guide portion 48 is at the correct position, the height is adjusted, and the shaft portion is fixed to the support portion 46 with the set screw 47. Then, as described above, when a voltage is applied to the laminated piezoelectric element 32, the laminated piezoelectric element 32 expands and contracts, the support part 46 moves in the axial direction, and the shaft part fixed to this also moves together, guiding the piezoelectric element 32. The height of section 48 changes.

Each embodiment of the present invention has been described above.

In each embodiment, the control amount for tracking, that is, the means for detecting the tracking error signal is not described because it is not directly related to the present invention, but a well-known pilot signal for tracking was used. It is obvious that the method used herein or other means can be applied.

〔Effect of the invention〕

As described above, according to the present invention, even if the number of magnetic heads increases, the internal structure of the cylinder does not become complicated.
Relative positional deviation between the magnetic heads can also be prevented, and moreover, so-called auto-tracking, in which the magnetic heads can be scanned along the curve of the tape pattern, can be performed without the need for power supply to the rotating section. Therefore, even when performing high-density recording, it is possible to record and reproduce signals with good reliability and high quality.

Also, even if the diameter of the cylinder becomes smaller, there will be no problem (
This makes it possible to downsize the entire device, and since all parts of the cylinder that come into contact with the magnetic tape are rotated, the friction between the cylinder and the magnetic tape is reduced, which allows the magnetic head to run at high speeds. It is possible to record and reproduce high-band signals.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a cylinder and its surroundings in one embodiment of the present invention, FIG. 2 is a sectional view showing a cross section of the cylinder in FIG. 1, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a sectional view showing a part of the cross section of the cylinder in the example, FIG. 4 is a perspective view showing the inlet side of the cylinder in another embodiment of the present invention, and FIG.
The figure is a sectional view showing the cross section of the width regulating tape guide in Figure 4.
It is. Explanation of symbols 1... Rotating magnetic head device (cylinder), 2... Rotating cylinder, 3... Magnetic head, 4... Fixed cylinder, 5... Laminated piezoelectric element, 6... Base, 7...
Cylinder base, 36...pin, 37...coil,
38... Yoke, 30... Width regulation tape guide, 3
2... Laminated piezoelectric element, 100... Magnetic tape. Agent Patent Attorney Akio Namiki Figure 4

Claims (1)

[Claims] 1. A helical scan comprising a cylinder on which a magnetic head is mounted, and a width regulating tape guide arranged near the cylinder and regulating the position in the width direction of the magnetic tape wound around the cylinder. In the magnetic recording and reproducing apparatus, all parts of the cylinder that come into contact with the magnetic tape, including the mounted magnetic head, are rotated around a certain rotation axis, and one of the cylinder and the width regulating tape guide is rotated. is fixed to a fixed part, the other is attached to the fixed part with an electromechanical transducer interposed therebetween, and a voltage or current is supplied to the electromechanical transducer to drive the electromechanical transducer. Alternatively, one of the width regulating tape guides attached to the fixed part via the electromechanical transducer is displaced relative to the fixed part in the axial direction, so that the magnetic head and the magnetic tape are aligned relative to each other. A helical scan magnetic recording and reproducing device characterized in that the position is controlled. 2. The helical scan magnetic recording and reproducing apparatus according to claim 1, wherein the electromechanical transducer is a laminated piezoelectric element configured by laminating piezoelectric elements. playback device.