JPS59162617A - Rotary magnetic head device - Google Patents

Abstract

PURPOSE:To set easily with high precision a magnetic head to the prescribed position of a rotary drum by fixing the magnetic head to two arc-shaped piezo-oscillators and attaching each oscillator to a supporting member and fixing the supporting member to a prescribed position of the rotary drum so that it can be adjusted finely. CONSTITUTION:A magnetic head 25 is fixed to the middle position of a half ring-shaped piezoelectric bimorph 20. Both end parts of the bimorph 20 are fixed temporarily to a pedestal part 31 of a supporting plate 30. The supporting plate 30 is fixed temporarily to a groove 42 of a rotary drum 40. When an eccentric shaft 60 is rotated in directions of arrows A and A', an eccentric shaft part 60a is turned, and its circumferential face presses the supporting plate 30 to displace it in the direction of an arrow B. Consequently, a projection quantity (d) of a magnetic head chip 28 from a rotary drum circumferential face 40b is adjusted. Similarly, the eccentric shaft part 60a is brought into contact with a projection 35 of the supporting plate 30, and the chip 28 is so adjusted that it is set to a prescribed angle calculation position on an end face 40b of the drum 40. Further, the projection quantity of a screw 51 to the side of an end face 40a is adjusted to set the head chip 28 to a set reference face. The same operation is performed for another one set of head units.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a rotating magnetic head device for magnetic recording and reproduction.

2. Description of the Related Art Conventionally, as a rotary magnetic head device for magnetic recording and reproduction in a VTR, (video tape recorder), etc., a device constructed as shown in FIGS. 1 to 3, for example, is known.

That is, an annular groove 2 is formed on one end surface of the rotary F ram 1, which transports the magnetic strip 14 while being wound around the circumferential surface 1b.
is provided in the annular groove 2, and a ring-shaped support plate 4 having supporting protrusions 3-1 and 3-2 at positions 180° apart from each other, and a magnetic support plate 4 having supporting protrusions 3-1 and 3-2 located at 180° from each other. A ring-shaped piezoelectric bimorph 6 to which a recording/reproducing magnetic head 5-1, 5-2 is fixed is fitted. and,
Presser plates 8-1 and 8-2 are attached to the end surface 1a of the rotating drum l via screws 9, and correspond to intermediate positions between the magnetic heads 5-1 and 5-2 on one surface of the piezoelectric bimorph 6. The two parts are clamped by the protrusion 7-1 of the press plate 8-1 and the protrusion 3-1 of the support plate 4, and by the protrusion 7-2 of the press plate 8-2 and the protrusion 3-2 of the support plate 4, respectively. be done.

The lower rotating drum 11 having the same diameter as the rotating drum 1 of the rotating drum unit IO formed in this way is:
Coaxially, it is integrally connected via a fixing disk 12 to a rotating shaft 13 driven by a motor (not shown). When this rotary shaft 13 rotates at a predetermined speed, the rotary drum unit l-10 and the lower rotary drum ]l rotate, and the rotating F RAM unit) 10 both magnetic heads 5-1
．． 5-2 comes into contact with the tape 14 to scan a predetermined position on the magnetic recording surface of the tape 14.

As shown in FIGS. 4 and 5, the piezoelectric bimorph 6 of the rotating drum unit 10 includes two ring-shaped piezoelectric diaphragms 6-1. , 6-2 are pasted together. The electrode film formed on the bonded parts of both piezoelectric diaphragms 6-1 and 6-2 is divided into half electrodes 6-10 and 6-20.
It is divided into two parts. And piezoelectric diaphragm 6-
Electrode 6-1 formed on the other surface of each of 1 and 6-2
2 and 6 to 22 and the electrode 6-IO, a tracking control signal generator 1 provided outside the device.
6-1, a voltage signal representing the scanning state of the magnetic tape 14 is applied/JD via a rotary transformer 17 mounted in the lower rotating drum 11. Similarly, both electrodes 6-12 and 6-22 and the electrode 6-20
Another tracking control signal generator 16 is connected between the
-2 through the rotary transformer 17, (m
A voltage signal representing the scanning state of the 9C tape 14 is applied.

A portion of the piezoelectric bimorph 6 corresponding to the electrode 6''I OK and a portion corresponding to the electrode 6-20 are respectively bent with a strain amount on the μm order in response to the above-mentioned voltage signal, and the portions of the piezoelectric bimorph 6 that correspond to the electrode 6"I -2 is a so-called dynamic tracking method in which magnetic recording and reproducing operations are performed using the so-called dynamic tracking method, in which the rotary tram 1 is displaced in the axial direction and controlled to scan a predetermined portion of the magnetic recording surface of the magnetic tape 14. It has become.

In this way, in the rotating magnetic headl-' device,
Based on the amount of distortion in the μm order of the piezoelectric bimorph 6,
Magnetic f-)i of two magnetoelectric heads 5-1.5-2
4, the precision of the set positions of both magnetic heads 5-1 and 5-2 on the rotating drum 1 is required to be on the order of micrometers or higher. For example, the amount by which each magnetic head 5-1.5-2 protrudes outward from the circumferential surface 1b of the rotating F-ram 1 is approximately 4o to 50 μm, and both magnetic heads 5-1.5-2 are rotated. drum l
The deviation tolerance of both magnetic heads I"5-1.5-2 with respect to the angle indexing line (shown by the two-dot chain line in Fig. 2) for setting them at positions 180' apart from each other on the end face 1a of the magnetic head I"5-1.5-2 is ±8 μm. is within the range of both magnetic heads 5-1.5-2.
The deviation tolerance with respect to the distance (see FIG. 3) from the reference plane, for example, the end Ufriia of the rotating drum 1, is within the range of ±2 μm.

However, in the above-mentioned conventional rotating magneto-electric head device, since the two magnetic heads 5-1 and 5-2 are fixed to one piezoelectric bimorph 6, each magneto-electric head 5-1 is attached to the rotating drum l. .5-2 cannot be finely adjusted individually, and in order to obtain the above-mentioned position setting accuracy, it is necessary to fix both magnetic heads 5-1 and 5-2 to the piezoelectric bimorph 6 by μm. The precision required was higher than the order, and the assembly work required a lot of effort. In addition, the shape of the piezoelectric bimorph 6 to which each magnetic head is fixed,
Since the dimensions of the piezoelectric bimorph 6 cannot be finely adjusted as described above, the shape and dimensions of the piezoelectric bimorph 6 are required to have high precision, and the cost of the piezoelectric bimorph 6 increases accordingly. Therefore, the manufacturing cost of the entire device was extremely expensive.

Purpose: The present invention solves the above-mentioned problems by making it possible to set two magnetic heads at predetermined positions on the end surface of a rotating drum in a finely adjustable manner individually. An object of the present invention is to provide a rotary magnetic head device that can be manufactured at low cost and that can easily set two magnetic heads at predetermined positions with the required high precision.

EMBODIMENT OF THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 6 shows a rotating drum unit for magnetic recording and reproduction in a video tape recorder.

In FIG. 6, 2o is a piezoelectric bimorph formed in the shape of a half ring, and this piezoelectric bimorph 2° is formed by bonding two piezoelectric diaphragms 21 and 22 with their polarization axes aligned. This piezoelectric bimorph 20 has a common electrode film 2 formed between the two piezoelectric diaphragms 21 and 22 pasted together.
3-1. O, and electrode films 23-21.0 formed on the other surface of each piezoelectric diaphragm 21.22. , 23-22. A tracking control voltage signal for the magnetic tape of the magnetic head is connected between the common electrode film 23-1 and the two power films 23-21 and 23-22 via a 'J-T wire (not shown) in a known manner. or is applied.

A magnetic head 25 for magnetic recording and reproduction is fixed at an intermediate position on one surface of the bimorph 20. This magnetic head 25 has a head base 26 made of a substantially T-shaped non-magnetic plate, and a magnetic head chip 28 for magnetic recording/reproduction protrudes by a predetermined amount from the tip surface 26a of the base 26 of the spatula 1. It is installed like this. Note that this magnetic head chip 28 is a well-known one, and a detailed explanation of the structure and illustration of the entire chip will be omitted.

Furthermore, at an intermediate position of the inner side ifm 20 c of the piezoelectric bimorph 20, a semicircular cutout 24, for example, is provided to indicate the intermediate position. Note that this notch 24 is
It may be provided on the outer surface 20d of the pressure T bimorph, or it may be formed in a semicircular shape, for example, in a 7-shape.

Reference numeral 30 denotes a support plate for supporting the piezoelectric bimorph formed in a substantially semicircular shape, and support pedestals 31-1.81 for supporting both ends of the piezoelectric bimorph 20 are provided at both ends of the support plate 30.
-2 is formed. These support pedestals 31-1.
31-2 is provided with grooves 32-1 and 32-2 into which both ends of the piezoelectric bimorph 20 fit, respectively.

A hole 34 for fixing to the rotary tram 40, which will be described in detail later, and a rectangular plate-shaped protrusion 35 for adjusting the fixing position are formed in the middle of the support plate 30. .

40 is a rotating drum that transports the magnetic tape while wrapping it around its circumferential surface. This rotating drum 40 is provided with a through hole 41 for attaching a rotating shaft along the axial direction. and,
One end surface 4 of the rotating drum 40. Oa K is provided with an annular groove 42 into which the support plate 30 is fitted. Further, the two support plates 30 (only one is shown in FIG. 6) are provided with grooves 43-1 and 43-2 into which the protrusions 35 of each support plate 80 are fitted, at positions 1800 degrees apart from each other. Threaded holes 44-1 and 44-2 for fixing and tapped holes 45-1 and 45-2 for adjusting the distance from the setting reference plane of the support plate.
and is provided. Furthermore, each screw hole 44, -1,
The end faces 4.4 of the rotating drum 40 are respectively disposed around the circumferential portions of the rotating drums 44-2. Three holes 46-11.46-12°46-13 are provided for adjusting the fixed position of the support plate relative to Oa. As will be described in detail later, the eccentric shaft 60 is inserted into these holes 46-1, 46-12, and 46-13, and the fixed position of the support plate 30 is adjusted by rotating the eccentric shaft. It's meant to be fine-tuned.

First, we will explain how to assemble the upper NB rotating drum unit.

First, the magnetic head chip 28 of the magnetic head 25 is placed at an intermediate position on one side of the piezoelectric bimorph 20, for example, on the electrode film 23-21 side, using an adhesive not shown in the drawing. The head base 26 of the magnetic head 25 is fixed. Both ends 2 of this piezoelectric bimorph 20
0-1.20-2, the support pedestal part 31-1 of the support plate 30
．． Insert it into the grooves 32-1 and 32-2 of 31-2 and temporarily fix it.

Next, the support plate 3 to which the piezoelectric bimorph 20 is temporarily fixed
0 is fitted into the groove 42 of the rotating drum 40, and the protrusion 35 of the support plate 30 is fitted into the groove 43-1.

Then, using the support plate 30 and the screws 50, the support plate 3
0 hole 341 is temporarily secured through the screw hole 44-1 of the rotating drum 40.

Thereafter, as shown in FIG. 8, the eccentric shaft 60 is inserted into the hole 4.
6-11 and rotate the eccentric shaft 60 as shown by arrows A and A' in FIG. 8, the cylindrical eccentric shaft portion 60a of the shaft 600 rotates. The circumferential surface of the support plate 60a presses the inner surface 30C of the support plate 30 to displace the support plate 30 in the direction shown by arrow B in FIG. In this manner, by appropriately rotating the eccentric shaft 60, as shown in FIG. The protrusion amount d is adjusted to approximately 40 to 60 μm. Similarly, by inserting the eccentric shirt 1-60 into the hole 46-12 or the hole 46-13 of the rotary drum 40 and rotating it, the eccentric shaft portion 60a of the eccentric shaft 60 is connected to the support plate 30. One side 35 of the protrusion 35
b, and the magnetic head tip 28 is adjusted to be set at a predetermined angular index position on the end surface 40b of the rotating drum 40. As shown in FIG. 7, this angle indexing position is such that the magnetic helad tips 28 on the two piezoelectric bimorphs 20 mounted on the end surface 40a of the rotating drum 40 are mutually aligned with respect to the center on the end surface 40a. This is a position that makes an angle of 180°.

In this way, the support plate 30, and therefore the magnetic herad tip 28 fixed to the piezoelectric bimorph 20, can be accurately set at a predetermined angular index position on the end face 40a of the rotary tram 40.

After that, the screws 50 are completely tightened, and both ends 20-1.20=2 of the piezoelectric bimorph 20 and the support pedestal 31-1.31-2 are fixed using an adhesive (not shown). do.

In the same manner as described above, another set of magnetic head units, which is a combination of the piezoelectric bimorph 20 to which the magnetic head 25 is attached and the support plate 3o, is attached at a predetermined angle on the groove 43-2 side of the end surface 40a of the rotating drum 40. Can be installed in an indexed position.

Furthermore, as shown in FIG. 8, screw the screw 51 into the screw hole 45-1 of the rotating drum 40 using a hexagonal wrench 61 or the like, and push the screw 51 toward the end surface 40a side of the rotating F-ram 40. By adjusting the protrusion amount of the magnetic head unit (Dm9), the head chip 28 is placed on the set reference surface,
It is set to be spaced a predetermined distance H (shown in FIG. 8) from the end face 40a of the end face 40a of the end face 40a of the end face 40a. Another piezoelectric bimorph 20
The distance H is adjusted in the same manner for the magnetic head chip 28 attached to the magnetic head chip 28 . The difference in distance between these two magnetic head chips 28 from the setting reference plane 40a is adjusted to be within a range of about ±2 μm, for example. The rotating drum unit 48 is now obtained.

A plan view of this rotating drum unit 48 is shown in FIG.

The second rotating 1-ram unit 48 is used in combination with the lower rotating tram, fixed disk, rotating shaft, etc., as in the rotating magnetic head device shown in FIG. 3 described above, to produce the rotating magnetic head shown in FIG. Get the equipment.

In FIG. 10, parts equivalent to those in FIG. 3 are given the same reference numerals, and explanations of those parts will be omitted.

In the rotating magnetic head' device having the above configuration, the magnetic head 25 is bubbled to each of the two separate (hard) half-ring shaped piezoelectric bimorphs 20, while each piezoelectric bimorph 2
0 are attached to separate support plates 30, and the rotating drum 4
Since each support plate can be placed in a predetermined position relative to the end face 40ai/l of 0 in a finely adjustable manner, the accuracy of setting the magnetic head 25 to the piezoelectric bimorph 20 can be eased accordingly. The two magnetic heads 25 can be set at predetermined positions on the rotating drum 40 with high precision without requiring much effort. Further, since the shape and dimensional accuracy required for the piezoelectric bimorph 20 can be relaxed, the manufacturing cost l- of the piezoelectric bimorph 20 can be reduced accordingly.

In addition, in the actual gun example mentioned above, the piezoelectric bimorph 20
is supported on the support plate 80 in the form of a beam supported on both sides, but as shown in FIGS. 10 and 11, the support plate 30, one end of the piezoelectric bimorph 20 is fixed to the support pedestal 32', and a magnetic spatula t'' 25 is attached to the other end of the piezoelectric bimorph 20.
may be fixed to support the piezoelectric bimorph 20 in a cantilever form. Thereby, as described above, it is possible to increase the amount of displacement of the IEF ram 40 in the axial direction when a voltage signal for scan control is applied to the piezoelectric bimorph 20. That is, the scanning control range can be increased.

Moreover, the piezoelectric bimorph 20 in the embodiment described above is
It is limited to a half-ring shape, but a shape extending in an arc having a shorter length can also be used. Furthermore, in place of the piezoelectric < Imo I Ref 20, 1
A piezoelectric diaphragm split in half or extending in an arc shape may be used.

Effects As is clear from the above explanation, according to the present invention, two magnetic heads for magnetic recording and reproduction are respectively fixed to two separate arc-shaped piezoelectric vibrators, and each piezoelectric vibrator is Since the individual supporting members are finely adjustable and fixed at predetermined positions on the end surface of the rotating tram for transporting magnetic tape, the required high setting positions of both magnetic heads on the end surface of the rotating drum can be easily adjusted. Accuracy can be ensured without having to attach the magnetic heads to predetermined positions on the piezoelectric vibrator with such high precision, and two magnetic heads are fixed to one link-shaped E'fE vibrator that is attached to a rotating tram. In contrast to the conventional type of apparatus, the rotary magnetic head apparatus can be assembled easily without requiring much effort. Also,
The shape and dimensional accuracy required for the piezoelectric vibrator itself can be relaxed, and the cost of the piezoelectric vibrator can be reduced accordingly. Therefore, the manufacturing cost of the entire device can be reduced to approximately 11W compared to conventional types of devices.

[Brief explanation of drawings]

1 is an exploded perspective view of the main components of a conventional rotary magnetic head device, FIG. 2 is an external perspective view of the main components of FIG. 1, and FIG. 3 is a vertical cross-section of the device of FIG. 1. 4 and 5 are diagrams for explaining the configuration of the piezoelectric bimorph in the device shown in FIG. 2, and FIG. 6 is an exploded perspective view of the main components of the rotating magnetic head device according to the present invention. FIG. 7 is an external perspective view of the main components shown in FIG. 6, FIG. 8 is a diagram for explaining how to adjust the set position of the magnetic head when assembling the components shown in FIG. 6, and FIG. FIG. 10 is a longitudinal cross-sectional view of a rotating magnetic head device according to an example of the present invention, and FIG. Fig. 12 is a plan view of the main components of another example of a real gun.
12 is an external perspective view of a support plate that can be used for the main components of FIG. 11. FIG. ]1...Lower rotating drum, 12...Connection disc, 1
3. Rotating shaft, 14... Magnetic tape, 16~], 16-2... Scanning control signal generator, 17
・・Rotating type) Lance, 20 ・・Piezoelectric bimorph, 20
-1.20-2...Both ends of piezoelectric bimorph, 21.
22・Piezoelectric imaging plate, 23-10・Common electrode, 23-
21.28-22・Electrode, 24・Positioning arrow part, 25・Magnetic head′, 26・・Head base, 28・
Magnetic head chip, 30...Support plate, 31-1. ．． 3
1-2...Support pedestal part, 32-1.82-2 Fitting groove, 34...Fixing hole, 35...Protrusion for setting position adjustment, 40...Rotating drum, 40a... ...End face (setting reference surface), 42...Groove for fixing the support plate. 4B-1, 43-2... Groove for fitting protrusion on support plate, 4
4-], 44-2 Threaded hole for fixing support plate, 45-
1.45-2...Threaded hole for adjusting the support plate setting position, 4.6
-11,4] -12,46-13,46-21,4,6
-22, 46-23...Hole for adjusting the support plate setting position,
50.51...screw, 60...eccentric shaft. Patent applicant: Sharp Co., Ltd. Representative Patent Attorney Aoyama Hogai (2 persons)

Claims (1)

[Claims] (1) Two magnetic heads for magnetic recording and reproduction are attached to a piezoelectric vibrator attached to the end face of a rotating drum that transports the magnetic tape while being wrapped around the circumferential surface, and a predetermined control voltage signal is applied to the piezoelectric vibrator. In the rotary magnetic head device, both magnetic heads are displaced in the axial direction of the rotary drum by applying the above magnetic tape to scan a predetermined position on the magnetic recording surface of the magnetic tape. The magnetic head is fixed to each of the two piezoelectric vibrators, each piezoelectric vibrator is attached to a support member, and both support members are fixed to a predetermined position on the end face of the rotary drum so as to be finely adjustable. A rotating magnetic head device.