JPS5853408B2 - Rotating magnetic head device - Google Patents

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. This method uses two bending vibrators made by laminating two sheets together, and attaches a magnetic head to each to obtain clear reproduced images.It also simplifies the work of attaching the magnetic heads and improves assembly accuracy. It is something that makes you

In a magnetic recording/reproducing apparatus, a rotating magnetic head must be accurately scanned over a recording track of a magnetic tape in order to obtain an accurate reproduction signal.

For this reason, automatic tracking is performed to automatically move the reproducing magnetic head to the center of the recording track when the reproducing magnetic head deviates from the recording track.

Furthermore, automatic tracking must be performed when the running speed of the magnetic tape is arbitrarily changed during reproduction.

As the automatic tracking means, a rotating magnetic head height variable means using a bimorph vibrator made of two strip-shaped piezoelectric vibrators bonded together is interposed between the rotating magnetic head and the rotating shaft of the drum motor. has been taken.

-However, in these rotating magnetic head devices, the distance from the periphery of the rotating cylinder to the rotating shaft of the drum motor is short, so in order to obtain a predetermined displacement, the thickness of the bimorph vibrator must be made thin.

For this reason, the piezoelectric vibrators to be bonded together are thin and small, resulting in poor workability and being easily broken, making them difficult to handle.

Therefore, the work is time consuming and costs increase.

The present invention eliminates these drawbacks and provides a rotary magnetic head device equipped with a strong piezoelectric vibrator that is easy to work with.

An embodiment of the rotary magnetic head device of the present invention will be described in detail below with reference to FIGS. 1 to 5.

In FIG. 1, reference numeral 1 denotes a rotating cylinder fixed to a drum motor, and a piezoelectric vibrator mounting jig 3 is attached to the rotating cylinder.
, 3' is used to form a piezoelectric vibrator (hereinafter referred to as a bending vibrator) obtained by laminating two semicircular vibrators in the form of partial annular vibrators. 2 and 2' are at both ends. head substrates 4, 4' fixedly mounted and having a magnetic head 5° 5' mounted at the center of each of the bending vibrators 2, 2';
is glued.

To explain the bending oscillators 2, 2' in more detail with reference to FIG. 2, they are two semicircular oscillators 2A, 2B pasted together so that their polarization directions (arrows in the figure) are aligned.
In order to take out the electrodes on the bonded surface, one semicircular ring vibrator 2B is lengthened by portions 6 and 6'.

In addition, the upper surfaces of the two semicircular oscillators 2A and 2B are electrically short-circuited to form a common electrode 7.
Take out the electrode 8 from the bonded part of B, and connect the electrodes 7 and 8.
When a DC voltage is applied to the bending vibrators 2, 2', as shown in Figure 1, both ends of the bending vibrators 2, 2' are fixed. It will bend a lot.

Therefore, the track deviation of the magnetic head is detected, a signal corresponding to the detected amount is input to the piezoelectric element drive circuit, the output is applied to the electrodes 8 and 7, and the bending vibrator is swung to displace the magnetic head. The aim is to obtain a good reproduced signal.

As mentioned above, in the present invention, unlike the conventional rectangular plate, the bending vibrator has a semicircular shape, so the effective displacement length can be longer, so the bending vibrator can be made thicker if the same displacement is to be obtained. It is noteworthy that it is sturdy, easy to handle, and improves workability.

In addition, although the bending vibrator shown in FIG. 2 has been described as an embodiment of the present invention, the two-piece semicircular ring vibrator 2A
, 2B shows an embodiment in which the electrodes can be taken out from the bonded surface by changing the inner diameter of one of the electrodes.

FIG. 4 shows bending oscillators 2 and 2 attached to a rotating cylinder so that the polarization directions of the pasted semicircular oscillators 2A and 2B are reversed.
′ is shown.

The arrow indicates the polarization direction of the semicircular ring oscillator.

In this case, the magnetic head moves in the opposite direction when driving signals of the same phase are applied to the two bending vibrators, so there is a great advantage that only one circuit configuration is required.

FIG. 5 shows a magnetic head 9 for recording on the rotary cylinder 1.
9' is shown.

Since the bending vibrators 2 and 2' have residual displacement after driving,
If the magnetic tape is recorded in this state, it may cause track misalignment and become incompatible when used with other devices.

To prevent this, a magnetic head 9°9' fixedly attached to the rotary cylinder 1 is used for recording, and the bending vibrator 2
, 2' are used only for reproduction.

As described above, according to the present invention, it is possible to obtain a rotary magnetic head device of a variable height type, which has a bending vibrator that is thicker and stronger than the conventional one, and which is easier to handle and thus improves workability.

Furthermore, according to the present invention, since the piezoelectric vibrator can be made larger than a strip-shaped piezoelectric vibrator, the mass of the magnetic head can be made relatively small compared to the mass of the piezoelectric vibrator, and the effect of attaching the magnetic head on the characteristics can be reduced. This results in stable long-term properties.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing a state in which a bending vibrator is attached to a rotary cylinder showing one embodiment of the present invention, and FIG. 1b is a side view of the same.
2 and 3 are perspective views showing a bending vibrator used in the present invention, FIG. 4 is a side view of a bending vibrator showing another embodiment of the present invention, and FIG. 5a is a perspective view showing a bending vibrator used in the present invention. A plan view of still another embodiment of the present invention, and b is a side view of the same. 1...Rotating cylinder, 2, 2'...Bending vibrator, 2A, 2B...Semi-circular piezoelectric vibrator, 5, 5'... Magnetic head, 9, 9'...
...Fixed magnetic head.

Claims (1)

[Claims] 1. A magnetic head is attached to each of two semicircular bending vibrators made by laminating two semicircular piezoelectric vibrators having polarization axes in the thickness direction, and A rotating magnetic head device characterized in that both ends of both bending vibrators are attached to a rotating cylinder. 2. The rotary magnetic head device according to claim 1, wherein the two semicircular piezoelectric vibrators constituting the bending vibrator have different inner diameters. 3. The rotary magnetic head device according to claim 1, wherein the two semicircular piezoelectric vibrators constituting the bending vibrator have different lengths. 4. The rotating magnetic head device according to claim 1, wherein the two bending vibrators are attached to a rotating cylinder so that their polarization directions are opposite to each other. 5. The rotating magnetic head device according to claim 1, wherein a recording magnetic head is fixedly attached to a rotating cylinder.