JPH03165310A - Rotary magnetic head assembly - Google Patents

Abstract

PURPOSE:To move the magnetic head in the direction of tape width within an optional movable range and to hold and fix the magnetic head at constant height by putting a radial movable in reciprocal motion by a driving source. CONSTITUTION:The rotary part 40 a of an ultrasonic motor 40 is put in reciprocal motion in the rotating direction within ranges 33a and 33b to perform the specific reciprocal motion radially by a spring 37 according to the irregularity of the outer periphery of a cam 39. Further, when recording is carried out by a magnetic head 16, the ultrasonic wave motor 40 is fixed while the groove part of the cam 39 for fixation is brought into contact with a rod 38, and consequently magnetic heads 16 which face each other at 180 deg. can be fixed at the same height in the width direction of the magnetic tape 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating magnetic head assembly for a magnetic recording/reproducing device such as a video tape recorder.

[Prior Art] FIG. 5 is a sectional view showing the main parts of a rotary magnetic head assembly including a conventional magnetic head drive device, and FIG. 6 is a view taken along arrows Vl-VI in FIG. is the lower drum,
2 is a bearing attached to the lower drum l; 3 is a rotating shaft supported by the bearing 2 and rotates; 4 is a pedestal fitted to one end of the rotating shaft 3; 5 is attached to the pedestal 4 using a screw 6. 7 is a magnetic head drive device attached to the upper drum 5 using screws 8; 9 is a lower transformer attached to the lower drum 1; 10 is an upper transformer attached to the pedestal 4; 11
1 is a wiring board attached to the upper drum 5, 2 is a non-rotating contact for supplying control current to the magnetic head drive device 7, and 13 is provided on a part of the base 4 so as to be in sliding contact with the contact 12. Rotating electrodes! Reference numeral 4 designates a connection portion for electrically connecting the electrode 13 to the magnetic head drive device 7 via the connection portion 15 and the wiring board 11; 16 is a magnetic head attached to the magnetic head drive device 7; It is electrically connected to the upper transformer 10 via the plate 11 and the connecting portion 15. Reference numeral 18 denotes a recess provided in a part of the upper drum 5 to accommodate the magnetic head drive device 7, and is formed to be slightly larger than the magnetic head drive device 7 so that the position of the magnetic head 16 can be adjusted. I9 is a position adjustment hole for adjusting the position of the magnetic head 1G, and 20 is a magnetic tape that comes into sliding contact with the magnetic head 16. FIG. 7 is a view taken along the ■-■ arrow in FIG. 5 showing details of the magnetic head drive device, FIG. 8 is a sectional view taken along the ■-■ arrow in FIG. 7, and FIG. 9 is a front view of FIG. be.

In the figure, 21 is a first yoke made of magnetic material, 22
2 is a columnar first permanent magnet fixed to the first yoke 21;
3 has a first yoke 21 having a convex portion 23a on a part of its inner circumference.
24 is a third yoke made of magnetic material and is attached to the second yoke 23; 25 is a third yoke 24 with the same magnetic pole as the first permanent magnet 22 facing the second yoke; Fixed columnar second permanent magnet, 26
27 is a pole piece made of a magnetic material located between the second permanent magnet 25 and the first permanent magnet 22 and fixed to either one, and 27 is a thin non-magnetic material located between the third yoke 24 and the second yoke 23. A temporary spring having an extension part 27a made of material, the extension part 27a is connected to the third yoke 24 and the second yoke 2.
It protrudes outward through windows 24a and 23a provided in 3, and a magnetic head 16 is attached to the tip. 28 is a plate spring made of a thin non-magnetic material held between the first yoke and the second yoke; 29 is a temporary spring 27 and 2;
8 and 30, the inner circumference is the first
Permanent magnet 22 and second permanent magnet 25 and pole piece 2
6 and the bobbin is fixed to the fixing member 29 using adhesive 32, and 31 is in a position where there is a gap over the entire circumference between it and the convex portion 23a of the second yoke 23. It is a coil made of an electric wire having a covering material wound around a bobbin 30.

Next, the operation will be explained.

The first permanent magnet 22 is a pole piece 26. Second yoke 23
and the first yoke 21 to generate a magnetic flux. Similarly, the second permanent magnet 25 is the pole piece 26
．． A closed magnetic path formed by the second yoke 23 and the third yoke 24 generates a magnetic flux E in the opposite direction to the above magnetic flux, and both the magnetic flux and the magnetic flux E cross the annular gaps F and G in the same direction. The coil 31 includes a first permanent magnet 22 and a second permanent magnet 2.
A total of 5 magnetic fluxes cross. If current is applied to the coil 31 from the contactor 12 to the electrode 13 and through the connecting portion 15.14 in the above state, the coil 31, bobbin 30, and magnetic head I6 will move vertically in a parallel straight line as one. ,
The magnetic nozzle 16 is displaced in the width direction of the magnetic tape 20 so as to accurately trace the magnetic recording trace.

The magnetic head 16 also has a coil 31 wound around a bobbin.
By applying a constant current to the bobbin, the bobbin can be stopped and fixed in a fixed position.

[Problems to be Solved by the Invention] In the conventional magnetic head drive device as described above, the coil 3
When current is passed through coil 31. The bobbin 30 and the magnetic head 16 are integrated with the pole piece 26 and the permanent magnet 22.
Since the magnetic head 16 has a structure that performs parallel linear motion reciprocating in the tape width direction along the tape width direction 25, if the movable range of the reciprocating motion of the magnetic head 16 is to be made larger than before, it is necessary to increase the size of the components of the magnetic head drive device. The upper drum 5
Since the mounting space is limited, there are problems such as the magnetic head drive device not being able to be mounted on the upper drum 5. Furthermore, when recording and reproducing are performed using the same magnetic head 16, the magnetic head I6 is
If the position of the magnetic head 16 is fixed only by conventional electrical means, the magnetic head 16 may be fixed at a certain position due to reaction force when the magnetic head 16 enters the magnetic tape, disturbance to the device itself, etc. Since vibration occurs in the tape width direction together with the bobbin 30, there have been problems such as poor linearity of recording tracks and deterioration of image quality.

This invention was made to solve the above problems, and makes effective use of the limited space in a magnetic head drive device, and improves the movable range of the magnetic head 16 in parallel linear motion in the tape width direction compared to the conventional one. In addition, the magnetic head 16 can be fixed at a constant height without vibrating in the tape width direction even due to reaction force and disturbance when it enters the magnetic tape 20, and the magnetic head 16 can be fixed at a constant height. It is an object of the present invention to provide a magnetic head drive device that can sometimes obtain excellent linearity of recording tracks.

[Means for Solving the Problems] A rotating magnetic head assembly according to the present invention includes (1) a guide groove extending in the radial direction within a plane perpendicular to the rotation axis, and reciprocating motion in the radial direction along the guide groove; A first movable part that reciprocates along a guide groove provided in the tape width direction, and a second movable part that connects the first movable part and the second movable part to interlock them. a connecting member that allows
The magnetic head is mounted on a base disposed in the second movable part. Furthermore, (2) the magnetic head mounted on the movable part that reciprocates along the guide groove is arranged to face each other 180 degrees with the rotation axis as the center, and the magnetic head is arranged to face the rotation axis at 180 degrees; The magnetic heads are arranged to move vertically symmetrically in the width direction of the tape with the center at the center, and the magnetic heads arranged 180 degrees opposite each other are held and fixed at the same height with respect to the width direction of the tape. It is possible.

[Operation 1] The magnetic head drive device of the rotating magnetic head assembly according to the present invention has a cam formed with grooves 180 degrees symmetrical about the rotation axis and partially flat in the rotation direction. By rotating this cam, the movable part that can reciprocate linearly in the radial direction is moved in the radial direction by the unevenness of the cam groove, and the movable part that reciprocates in the width direction of the tape to which the magnetic head is fixed. , gives reciprocating motion in the tape width direction via the connecting member. In addition, by fixing the flat part of the cam groove in contact with the movable part in the radial direction, the magnetic head is fixed without vibrating due to reaction force or disturbance received from the magnetic tape. hold it in the same state.

[Example] Hereinafter, this invention will be explained with reference to the drawings.

FIG. 1 is an enlarged sectional view showing the main parts of a rotating magnetic head assembly according to an embodiment of the present invention. In the figure,
The ultrasonic motor 40 is a drive source for the magnetic head drive device 7, and a fixed part 40b is fixed to the pedestal 4, and a rotary part 40a is rotatably attached at a position facing the fixed part 40b. There is. Further, a cam 39 is fixed to the outer periphery of the rotating portion 40a so as to rotate together with the rotating portion 40a. The magnetic head drive device 7 is connected to the upper drum 5.
The rod 38 is attached to the cam 39 in such a manner that it is always in contact with the cam 39.

FIG. 2 is a front view of the magnetic head drive device according to the present invention. Reference numeral 33a designates a movable portion that performs reciprocating linear motion along a guide 1lf 134a provided in the width direction of the magnetic tape 20, to which the magnetic head 16 is fixed via a base 42 corresponding to the conventional extension portion 27a. 33b is a movable part that performs reciprocating linear motion along a guide groove 34b provided in the radial direction, and is connected to the movable part 33a via a connecting member 35 and a joint 36. Furthermore, spring 37
As a result, the movable portion 33b is pressed against the cam 39 via the rod 38.

FIG. 3 is a plan view showing a state in which the magnetic head drive device according to the present invention is attached to an upper drum.

The magnetic head drive device 7 is fixed to the upper drum 5 by a position adjustment bolt 41 such that the rod 38 is always in contact with the irregularities on the outer periphery of the cam 39. Further, two magnetic head drive devices 7 are attached to the upper drum 5 so as to be opposed to each other by 180 degrees around the rotating shaft 3, and the concave and convex shapes on the outer periphery of the cam 39 are also provided to be opposed to each other by 180 degrees. FIG. 4 is a plan view of the rotating part of the drive source of the magnetic head drive device according to the present invention. The unevenness formed on the outer periphery of the rotating part 40a is
39a for speed search (fast forward playback), 39b for high speed search (ultra fast forward playback), flat part 39c for fixing
It consists of three parts, each of which is formed 180 degrees opposite to each other, with a concave and convex shape that allows the magnetic heads 16, which are arranged 180 degrees opposite each other, to be driven in opposite phases in the width direction of the magnetic tape 20 at the same time.

In the magnetic head drive device configured as described above, the rotating part 40a of the ultrasonic motor 40 is connected to 33a, 33b.
By making a reciprocating motion in the rotational direction within each range of Let's do it. Movable part 33
The reciprocating motion in the radial direction of b is converted into a reciprocating motion in the width direction of the magnetic tape 20 of the movable section 33a via the connecting member 35 and the joint 36, and is thereby attached to the movable section 33a via the base 42. The magnetic head 16 also performs reciprocating motion in the width direction of the magnetic tape 20. The movable range of the magnetic head 16 in its reciprocating motion in the tape width direction can be adjusted arbitrarily by the depth in the radial direction of the unevenness provided on the outer periphery of the cam 39, and can be easily adapted to any special playback. can do. Also,
By providing the cam 39 with concave and convex portions facing each other 180 degrees around the rotating shaft 3 and having opposite phases, the magnetic heads 16 disposed 180 degrees opposite each other are given reciprocating motion with opposite phases in the width direction of the magnetic tape 20. be able to. When recording with the magnetic head 6, by fixing the ultrasonic motor 40 with the portion 39c in contact with the rod 38, the height of the magnetic tape 20 in the width direction of the magnetic head 16 facing 180 degrees can be increased. This makes it possible to fix the height to the same value.

In this embodiment, two magnetic heads 16 are mounted facing each other at 180 degrees, but they can be arranged depending on the desired structure, and the type of unevenness provided on the outer periphery of the cam (39) can also be changed according to this embodiment. In the example, three types are used, but the same can be said about the types and the shape of the unevenness. Further, in this embodiment, an ultrasonic motor, which is excellent in terms of responsiveness and large holding torque, is used as the drive source, but other equivalent motors may be used.

[Effect of the Invention 1 As described above, according to the present invention, the magnetic head attached to the movable part that reciprocates along the guide groove provided in the width direction of the magnetic tape is moved perpendicular to the rotation axis via the connecting member. The movable part that reciprocates along a guide groove provided in the radial direction in a plane is connected using a joint, so that by applying reciprocating motion to the movable part in the radial direction by a drive source, , it is possible to move the magnetic head in the tape width direction within an arbitrary movable range.

Further, by fixing the radially movable portion at a fixed position, it is possible to maintain and fix the magnetic head at a fixed height even if external force is applied from the magnetic tape.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing the main parts of a rotating head assembly according to an embodiment of the present invention, FIG. 2 is a front view of a magnetic head drive device according to the present invention, and FIG. 3 is a magnetic head according to the present invention. FIG. 4 is a plan view of the rotating part of the drive source of the magnetic head drive device according to the present invention, and FIG. 5 is a plan view of the rotating magnetic head drive unit including the conventional magnetic head drive device. 6 is a sectional view showing the main parts of the head assembly; FIG. 6 is a view taken along the line Vl--Vl in FIG. 5; FIG. 7 is a view taken along the line ■-■ in FIG. 5 showing details of the magnetic head drive device;
8 is a sectional view of FIG. 7, and FIG. 9 is a front view of FIG. 7. In the figure, l is the lower drum, 2 is the bearing, 3 is the rotating shaft, and 4
1 is a pedestal, 5 is an upper drum, 7 is a magnetic head drive device, 9 is a lower transformer, 10 is an upper transformer, 16 is a magnetic head, 2
0 is a magnetic tape, 21 is a first yoke, 22 is a first permanent magnet, 23 is a second yoke, 24 is a third yoke, and 25 is a second yoke.
Permanent magnet, 26 is a pole piece, 27.28 is a leaf spring,
30 is a bobbin, 31 is a coil, 33a, 33b are movable parts, 34a, 34b are guide grooves, 35 is a connecting member, 36
is a rotary joint, 37 is a spring, 38 is a rond,
39 is a cam, 40 is an ultrasonic motor, and 42 is a base. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A fixed cylinder that guides the magnetic tape to the outer peripheral surface;
A rotating magnetic head assembly for a magnetic recording and reproducing device, comprising: a rotating cylinder rotatably supported via a rotating shaft located in the center of the fixed cylinder, and supporting a magnetic head for recording and reproducing information on the magnetic tape. ,
a first movable part that is provided with a guide groove in the radial direction in a plane perpendicular to the rotation axis and reciprocates in the radial direction along the guide groove; and a first movable part that reciprocates along the guide groove provided in the tape width direction. A second movable part that moves, a connecting member that connects the first movable part and the second movable part and causes them to interlock, and a magnetic field attached to a base disposed on the second movable part. A rotating magnetic head assembly comprising a head. (2) The magnetic head mounted on the movable part that reciprocates along the guide groove is rotated once around the rotation axis.
The magnetic heads are arranged to face each other at 80 degrees, and the magnetic heads reciprocate vertically symmetrically in the tape width direction about the rotation axis, and further, the magnetic heads are arranged to face each other at 180 degrees. 2. The rotating magnetic head assembly according to claim 1, wherein the rotating magnetic head assembly can be fixed while maintaining the same height in the width direction of the tape.