JPS5919225A - Rotary magnetic head device - Google Patents

Abstract

PURPOSE:To set a magnetic head under the optimum tracking state and at the same time to facilitate processing and assembly, by reducing the width of the tip part of a flexural oscillator consisting of two circular piezoelectric oscillators bonded to each other less than the width of other part and attaching a magnetic head at the tip part. CONSTITUTION:The width of tip parts of circular piezoelectric oscillators 1 and 2 which are polarized in the thickness direction and have electrodes on each main surface is reduced to less than the width of other part. A part of the oscillator 2 is larger than the width of the part corresponding to the oscillator 2, and a magnetic head 3 is attached at the tip part of a flexural oscillator. This flexural oscillator is attached to a rotary cylinder 6 via an attachment part 4. The flexural oscillator works with the part 4 and the tip part defined as a fixed terminal and a free terminal respectively. In other words, the tip part has displacement in response to the level of the applied voltage. Therefore, an optimum tracking state is obtained by the control of the applied electric field. With use of a circular or oval flexural oscillator, the length of the oscillator is made larger than a rectangular flexural oscillator to ensure a larger displacement compared with the rectangular oscillator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary magnetic head device for a rotary head type magnetic recording/reproducing device, and a method for causing a reproducing magnetic head to automatically track a recording track on a magnetic tape during reproduction. In this case, a magnetic head is attached to the tip of a bending vibrator whose width at the tip is smaller than the width of the other parts.
The aim is to obtain clear reproduced images.

In a rotating head type magnetic recording/reproducing device, it is necessary to put the magnetic head in an optimal tracking state during playback, so a control signal is recorded on the magnetic tape during recording, and this control signal is used to control the rotating magnetic head during playback. This traces the recording tracks on the magnetic tape. However, trunk misalignment occurs due to expansion and contraction of the magnetic tape and differences between recording and reproducing devices. In addition, if the running speed of the magnetic tape during playback is changed from the speed during recording to obtain special reproduction images such as still images, low speeds, and high speeds, the position cannot be controlled using control signals, and the magnetic head will not be able to track the recording track. cannot be traced.

For this reason, automatic tracking is performed in which the height of the magnetic head is made variable and the head is moved to the center of the recording track. Conventionally, as a means of automatic tracking, a method has been used in which a rotating magnetic head is attached to the tip of a bending vibrator made by bonding two rectangular piezoelectric vibrators, and the height of the rotating magnetic head is varied. . However, in these rotating magnetic head devices, since the length from the circumference of the rotating cylinder to the rotating shaft of the drum motor is short, it is necessary to The thickness of the vibrator must be made very thin. Therefore, it is difficult to process the piezoelectric vibrator, and the process of gluing the magnetic head or attaching the bending vibrator to the rotating cylinder is sometimes easily damaged, resulting in low work efficiency. Furthermore, if the thickness of the bending vibrator is determined with ease of handling in mind, the applied electric field to obtain the amount of displacement required to achieve the optimum tracking state will be increased. This accelerates the deterioration of the characteristics of the piezoelectric vibrator, resulting in problems with its lifespan and reliability. Additionally, in the case of a rectangular bending vibrator like the one mentioned above, it must be attached to the rotating cylinder in one place, making it difficult to increase the precision of the attachment and making it unstable to fix the position of the magnetic head. It has disadvantages such as

In order to eliminate such drawbacks, the present invention is equipped with a bending vibration posture vibrator that can position the magnetic head in an optimal tracking state and reduce changes in the magnetic head position over time, thereby improving the efficiency of machining, assembly, and adjustment work. The purpose of the present invention is to provide a highly reliable rotating magnetic head device that contributes to the present invention.

Hereinafter, the present invention will be explained in detail using figures.

FIG. 1 is a plan view of a rotating magnetic head device according to an embodiment of the present invention, and FIG. 2 is a side view thereof.

In the figure, 1 and 2 are annular piezoelectric vibrators that are polarized in the thickness direction and have electrodes attached to their main surfaces. There is. A portion of the piezoelectric vibrator 2 has a width larger than a corresponding portion of the piezoelectric vibrator 1. This protruding portion is used for taking out the electrode. 3 is a magnetic head;
It is attached to the tip of a bending vibrator made of piezoelectric vibrators 1 and 2. 4 is a mounting portion for mounting the bending vibrator to the rotating cylinder 6, and 5 is a screw for mounting.

Reference numeral 7 denotes an electrode lead wire for applying an electric field to the bending vibrator, and the embodiment shown in the figure shows a driving method when the directions of the polarization axes of the piezoelectric vibrators are made the same. When the thermal theory and polarization axis direction are reversed, an electric field is applied accordingly.

In this rotary magnetic head device, the bending vibrator operates with the mounting portion 4 as the fixed end and the tip portion to which the magnetic head is attached as the free end, similar to a beam with one end fixed and the other end free. That is, when an electric field is applied to the bending vibrator, the tip to which the magnetic head is attached is displaced in accordance with the magnitude of the electric field, so that an optimal tracking state can be obtained by controlling the applied electric field. As shown in the figure, by using an annular or elliptical bending vibrator, the length of the bending vibrator can be made longer than that of a rectangular bending vibrator, so a larger displacement than a rectangular one can be achieved with the same electric field. In addition, by making the width of the tip smaller than the width of other parts, the bending rigidity of the tip can be reduced, and this effect makes it easier to use than a bending vibrator with the same shape.
It has been confirmed through experiments that the displacement can be increased by about 2° to 30% with the same electric field.

The rotary magnetic head device of the present invention can solve the conventional problems caused by making the piezoelectric vibrator thinner in order to obtain the necessary displacement, and the problem of poor mounting accuracy. However, by adopting a structure that reduces the bending rigidity of the tip, the above-mentioned improvements will be made even more remarkable since it is possible to obtain a large displacement compared to a circular or elliptic ring bending vibrator of the same shape in the same electric field. This has the effect of extending the life of the vibrator and increasing its reliability since the applied electric field for the required displacement can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a rotating magnetic head device according to an embodiment of the present invention, and FIG. 2 is a side view thereof. 1...Piezoelectric vibrator, 2...Piezoelectric vibrator, 3...Magnetic head, 4...Mounting part, 5
...Screw, 6...Rotating cylinder, 7.
...Electrode lead wire.

Claims (1)

[Claims] The width of the opposing tips of a toric or elliptic ring-shaped bending vibrator, which is made by laminating two toric or elliptic ring-shaped piezoelectric vibrators with polarization axes in the thickness direction, is set to be larger than the width of the other parts. A rotating magnetic head device characterized in that the device is made smaller and has a magnetic head attached to each of the tips and attached to a rotating cylinder.