JPH10105938A - Movable type magnetic head device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movable type magnetic head device attaining variable speed reproduction at high speed by stabilizing contact of a magnetic chip with the surface of a magnetic tape. SOLUTION: A bobbin 5 of a voice coil type actuator 1 is supported via an elastic supporting body for supporting its axial center to be always parallel to an axial center of a rotary cylinder by a supporting plate 15, and the supporting plate 15 is held via a projecting amt. adjusting means 7 for moving it in the radial direction B of the rotary cylinder by a fixing part of the actuator 1, and then the bobbin 5 is moved in the direction of its axial center by the actuator 1 to move a magnetic chip 21 in the same direction, and also a deviation in a position of the magnetic chip 21 in the radial direction B due to elastic deformation of the elastic supporting body by moving the bobbin 5 is corrected by moving the supporting plate 15 with the projecting amt. adjusting means 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head device used in a magnetic recording / reproducing apparatus and the like, and more particularly to a movable magnetic head device which moves its magnetic chip to follow a recording track of a magnetic tape. Things.

[0002]

2. Description of the Related Art In commercial or consumer VTRs, during variable speed playback such as stationary playback, slow playback, and high-speed playback, the rotation speed of a rotary cylinder equipped with a magnetic chip is constant and only the tape running speed is variable. In order to obtain a reproduced image without noise by making the magnetic chip follow the recording track of the magnetic tape recorded at normal speed, the magnetic chip is automatically moved while moving in the recording track width direction in synchronization with the rotation of the rotating cylinder. Tracking actuators have been developed that perform automatic tracking.

One example of a conventional magnetic head device is shown in FIG.
As shown in FIG. 12, as a tracking actuator, a bimorph piezo ceramic plate 22 having a structure in which two piezoelectric element plates are sandwiched between three electrodes is used, and a magnetic chip 21 is mounted on a tip portion thereof. The base is attached to the rotating cylinder 23. According to the direction and intensity of the voltage applied between the electrodes on both surfaces of the bimorph piezo ceramic plate 22, the tip of the bimorph piezo ceramic plate 22 is positioned in the cylinder axial direction A (recording track) as shown by the phantom line in FIG. The magnetic chip 21 can be moved in the axial direction A of the rotating cylinder 23 by bending in the width direction.

[0004]

However, in the above-mentioned conventional tracking actuator, as shown in FIG.
When the tip of the bimorph piezo ceramic plate 22 is bent, the change d in the amount of protrusion of the magnetic chip 21 in the radial direction B of the rotary cylinder 23 increases, and the magnetic chip 21 is inclined with respect to the surface of the magnetic tape. However, since the contact with the magnetic tape surface becomes unstable, there is a problem that noise may increase or a track signal may not be read.

In variable speed reproduction, as the variable speed reproduction speed increases, it is necessary to increase the amount of movement of the magnetic chip 21 in the axial direction A. For this purpose, the bimorph piezoelectric ceramic plate 22 requires a larger amount. However, there is a problem that it is difficult to further increase the speed of the variable speed reproduction because the change in the protrusion amount d also increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a movable magnetic head device in which the contact of a magnetic chip with a magnetic tape surface is stabilized and the speed of variable speed reproduction can be increased. .

[0007]

In order to achieve the above object, a movable magnetic head device according to the present invention has a head base in which a fixed portion of a voice coil type actuator is attached to a rotary cylinder, and a magnetic chip is fixed to a tip portion. Is mounted on a bobbin which is a movable portion of the voice coil type actuator, and the bobbin is supported on a support plate via an elastic support body which supports the bobbin so that its axis is always parallel to the axis of the rotary cylinder. The plate is held by the fixed portion via a protrusion amount adjusting means for moving the plate in the radial direction of the rotary cylinder,
The voice coil-type actuator moves the bobbin in the axial direction thereof to move the magnetic chip in the same direction, and the movement of the bobbin deforms the elastic support member in the radial direction of the magnetic chip. The configuration is such that the deviation to is corrected by the movement of the support plate by the protrusion amount adjusting means.

According to the movable magnetic head device of the present invention,
The movement amount of the magnetic chip in the recording track width direction can be increased by the voice coil type actuator, and the protrusion amount change means cancels out the change in the protrusion amount caused by the movement of the magnetic chip in the axial direction, thereby making the protrusion amount constant. Further, since the attitude of the magnetic chip moves without tilting, the contact of the magnetic chip with the surface of the magnetic tape is stabilized, and the speed of variable speed reproduction can be increased.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

The movable magnetic head device is connected to a rotary cylinder 23.
FIG. When reproducing at the same reproduction speed as the recording speed, the magnetic chip 21
3 is fixed at a certain position. The magnetic chip 21 is moved by the movable magnetic head device in synchronization with the rotation of the rotary cylinder 23 so as to follow the track of the recording tape during variable speed reproduction of an image. It moves in the tape track width direction).

A first embodiment of a movable magnetic head device according to the present invention, as shown in FIGS.
The fixed base 10 of the voice coil type actuator 1 is attached to the head base 20, and the head base 20 having the magnetic chip 21 fixed to the distal end is attached to the bobbin 5 which is a movable part of the voice coil type actuator 1, and the bobbin 5 has its axis centered. A pair of left and right support plates 15, 1 are supported via four elastic wires 8, which are always supported parallel to the axis of the rotary cylinder 23.
5 and the support plates 15 and 15 are
3 is held by the fixed base 10 via the protrusion amount adjusting means 7 for moving in the radial direction B.

In the movable magnetic head device, the voice coil type actuator 1 moves the bobbin 5 substantially in parallel with the axial direction A to move the magnetic chip 21 in the same direction A. The displacement of the magnetic chip 21 in the radial direction B caused by the elastic deformation of the elastic wire 8 due to the movement of the elastic wire 8 is corrected by the movement of the support plate 15 by the protrusion amount adjusting means 7.

The voice coil type actuator 1 includes two permanent magnets 3 and 3 having the same pole (S-pole) opposed to each other, and a center line sandwiched between the two permanent magnets 3 and
3 and four pole pieces 4 arranged in parallel with the axial direction A and four pole pieces 4 which are wound around a winding coil 6 and can be moved in the axial direction (axial direction A) by an external power supply (not shown). The bobbin 5 supported by the elastic wire 8 and the permanent magnets 3
Yoke 2 having a magnetic pole portion 13 (N pole) adjacent to the outer peripheral surface of bobbin 5 and housing
And a pair of left and right fixed bases 10, 10 fixed to the yoke 2 and attached to the rotary cylinder 23. Here, the four elastic wires 8 are arranged parallel to each other and substantially parallel to the radial direction B of the rotary cylinder 23.

The bobbin 5 has a head base 20 with a magnetic chip 21 adhered to the tip. The distal end of the elastic wire 8 is inserted and fixed in each of the four connecting portions 16 of the upper left and right pair and the lower right and left pair. These four elastic wires 8
The two upper elastic wires 8 are connected to the contact 24,
It is configured to also serve as a lead wire for supplying a current to the winding coil 6.

The protrusion amount adjusting means 7 has one end of the support plate 1 at one end.
5 and the other end is adhered to one of the fixed bases 10, and the dimension is changed by an external power supply (not shown) to move the pushing point 19 to adjust the protrusion amount. It has a pair of laminated piezoelectric elements 9.

Each of a pair of left and right support plates 15, 15 is provided with two metal pieces 12,
Upper and lower fulcrums 18, 18 bonded via 12
And a pushing point 19 bonded to one of the laminated piezoelectric elements 9 via a metal piece 11, and a base end of the upper and lower two elastic wires 8 inserted and fixed near the distal end to support the bobbin 5. A plurality of support points 17, 17 are provided. The distance D between the fulcrum 18 and the pushing point 19 is configured to be much smaller than the distance C between the fulcrum 18 and the support point 17.

Each of the left and right laminated piezoelectric elements 9, 9 is formed by laminating a plurality of piezoelectric ceramic plates and electrode plates in order to maximize the dimensional change in the longitudinal direction (radial direction B). Still, this multilayer piezoelectric element 9
Since the displacement amount necessary for adjusting the protrusion amount cannot be sufficiently ensured by only the above, the addition of the displacement enlarging means including the support plate 15 as described above is required.

A method of moving the position of the bobbin 5 on which the magnetic chip 21 is mounted according to the first embodiment of the present invention will be described below with reference to the drawings.

When a current is applied to the winding coil 6 of the voice coil type actuator 1 from an external power supply, the bobbin 5 is changed depending on the direction and magnitude of the current, as shown in FIGS.
Moves up and down (axial direction A). At this time, since the bobbin 5 is supported by the four elastic wires 8 parallel to each other, the bobbin 5 moves in parallel without tilting in the vertical movement. At the time of variable speed reproduction, the direction and the magnitude of the current applied to the winding coil 6 are controlled in synchronization with the rotation of the rotary cylinder 23, so that the magnetic chip 21 is moved in the recording track width direction of the magnetic tape (axial direction A). To perform tracking. Moreover, at this time, since the bobbin 5 is supported by the four elastic wires 8 parallel to each other, the magnetic chip 21 does not tilt with respect to the surface of the magnetic tape. Also, in such a voice coil type actuator 1, large vertical movements can be repeatedly and easily performed with high accuracy as compared with the conventional bimorph piezo ceramic plate 22.

However, since the elastic wire 8 rotates about the support point 17 of the support plate 15, the bobbin 5 moves in the left-right direction (radius in FIG. It moves in the direction B). Therefore, as described below, the projecting amount adjusting means 7 is used to support the support point (the bobbin 5 via the elastic wire 8) of the support point of the support plate 15 so as to offset the movement of the bobbin 5 in the radial direction B. Support)
17 is moved in the radial direction B.

When a voltage is applied to the pair of left and right laminated piezoelectric elements 9 of the protrusion amount adjusting means 7 from an external power supply, as shown in FIG. 9 changes its dimension in the longitudinal direction (radial direction B), thereby displacing the pushing point 19 of the support plate 15;
Since the displacement in the radial direction B is restricted at the two upper and lower fulcrums 18 and only rotation is allowed, the bobbin 5 supported by the support point 17 moves in the radial direction B. At the time of variable speed reproduction, the direction and magnitude of the voltage applied to the multilayer piezoelectric elements 9
The magnetic chip 21 is moved in the radial direction B by controlling the bobbin 5 in synchronization with the rotation of the rotary cylinder 23 so as to cancel the movement in the radial direction B accompanying the movement in the axial direction A by the voice coil type actuator 1. To keep the amount of protrusion constant.

According to the first embodiment of the present invention, as described above, the movement amount of the magnetic chip 21 in the axial direction A can be increased by the voice coil type actuator 1, and the protrusion amount adjusting means 7, the magnetic chip 21
The change in the protrusion amount due to the parallel movement in the axial direction A can be canceled to make the protrusion amount constant, and the magnetic chip 21 moves in parallel without tilting.
Is stable, and the speed of variable speed reproduction can be increased. Further, since the elastic wire 8 also functions as an external power supply or a current supply unit to the winding coil 6, the structure is simplified and preferable.

A movable magnetic head device according to a second embodiment of the present invention has a rotary cylinder 2 as shown in FIGS.
3, a fixed base 10 of the voice coil type actuator 1 is attached, and a head base 20 having a magnetic chip 21 fixed to a tip end thereof is attached to a bobbin 5 which is a movable portion of the voice coil type actuator 1, and the bobbin 5 is attached to its axis. The flexible portion 3 of the leaf spring 31 is supported by four elastic wires 8 which are always supported so as to be parallel to the axis of the rotary cylinder 23.
4, the base 33 of the plate spring 31 is fixed to the yoke 2 of the voice coil type actuator 1, and a pair of left and right plates which push the plate spring 31 to move in the radial direction B of the rotary cylinder 23. The arms 35, 35 are held on the fixed base 10 via the protrusion amount adjusting means 14.

The voice coil type actuator 1 is the same as that of the first embodiment.

The projecting amount adjusting means 14 has one end adhered to the pushing point 19 of the plate arm 35 via the small metal piece 11 and the other end adhered to the one fixed base 10, and the dimensional change is performed by an external power source (not shown). And a pair of left and right laminated piezoelectric elements 9 for moving the pushing point 19 to adjust the amount of protrusion.

The two stacked piezoelectric elements 9 and 9 and the two fixed bases 10 and 10 are the same as those in the first embodiment.

The plate-like spring 31 has a base 33 fixed to the yoke 2 and a flexible portion 34 provided with a bobbin support point 32.
The flexible portion 34 is always in contact with the action points 36, 36 of the plate arms 35, 35 by the elastic force of the plate spring 31, and moves in the radial direction B by the movement of the plate arms 35, 35. It is configured.

Two pairs of upper and lower fulcrums 18, which are adhered to one fixed base 10 via two small metal pieces 12, 12 in the vicinity of the base end, respectively, on the pair of left and right plate-like arms 35, 35,
18, a pushing point 19 adhered to one of the laminated piezoelectric elements 9 via the small metal piece 11, and a leaf spring 3 near the distal end.
An action point 36 for pushing the first flexible portion 34 is provided. The distance F between the fulcrum 18 and the pushing point 19 is much smaller than the distance E between the fulcrum 18 and the action point 36.

According to the second embodiment of the present invention, the same functions and effects as those of the first embodiment can be obtained.

[0030]

According to the movable magnetic head device of the present invention, the movement amount of the magnetic chip in the recording track width direction can be increased by the voice coil type actuator, and the axial amount of the magnetic chip can be adjusted by the protrusion amount adjusting means. The change in the amount of protrusion due to the movement of the magnetic tape cancels out the amount of protrusion, and the magnetic chip moves without tilting, so that the contact of the magnetic chip with the magnetic tape surface is stabilized,
The speed of variable speed reproduction can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view from the front showing a first embodiment of the present invention.

FIG. 2 is a rear perspective view showing the first embodiment of the present invention.

FIG. 3 is a partial cross-sectional plan view showing the first embodiment of the present invention.

FIG. 4 is a left side sectional view showing the first embodiment of the present invention.

FIG. 5 is a sectional view showing an attached state of the movable magnetic head device of the present invention.

FIG. 6 is a schematic cross-sectional view illustrating the operation of a voice coil type actuator of the movable magnetic head device according to the present invention.

FIG. 7 is a front perspective view showing a second embodiment of the present invention.

FIG. 8 is a rear perspective view showing a second embodiment of the present invention.

FIG. 9 is a partially sectional plan view showing a second embodiment of the present invention.

FIG. 10 is a front perspective view showing a movable unit according to a second embodiment of the present invention.

FIG. 11 is a sectional view showing an attached state of a conventional movable magnetic head device.

FIG. 12 is a schematic plan view showing an attached state of a conventional movable magnetic head device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Voice coil type actuator 5 Bobbin 7, 14 Projection amount adjusting means 8 Elastic wire 9 Laminated piezoelectric element 10 Fixed base 11, 12 Small metal piece 15 Support plate 17, 32 Support point 18 Support point 19 Pushing point 20 Head base 21 Magnetic chip Reference Signs List 23 Rotating cylinder 31 Plate spring 33 Plate spring base 34 Flexible portion of plate spring 35 Plate arm 36 Point of action A Axial direction of rotating cylinder B Radial direction of rotating cylinder

Continued on the front page (72) Inventor Takafumi Nishino 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A fixed portion of a voice coil type actuator is attached to a rotary cylinder, a head base having a magnetic chip fixed to a tip portion is attached to a bobbin which is a movable portion of the voice coil type actuator, and the bobbin has an axial center. The support plate is supported by a support plate through an elastic support that is always parallel to the axis of the rotary cylinder, and the support plate is fixed to the fixed portion through a protrusion amount adjusting unit that moves the support plate in the radial direction of the rotary cylinder. The voice coil type actuator causes the bobbin to move in the axial direction to move the magnetic chip in the same direction, and the movement of the bobbin causes the elastic support to be elastically deformed. The deviation in the radial direction is configured to be corrected by the movement of the support plate by the protrusion amount adjusting means. Movable magnetic head apparatus according to claim and. 2. The movable magnetic head device according to claim 1, wherein the driving means of the protrusion amount adjusting means is a piezoelectric element. 3. The movable magnetic head device according to claim 1, wherein the elastic support member is formed of four parallel elastic wires whose tips are fixed to the left and right of the upper part and the left and right of the lower part of the bobbin. . 4. The movable magnetic head device according to claim 2, further comprising a displacement magnifying mechanism for moving the support plate by enlarging the displacement of the piezoelectric element. 5. The movable magnetic head device according to claim 3, wherein the two elastic wires are configured to also serve as a current supply unit to the voice coil type actuator.