JPH0340210A - Magnetic head driving device - Google Patents

Abstract

PURPOSE:To improve linearity by turning an internal yoke member, which is composed of triangle pole-shaped upper and lower permanent magnets pivotally supported to an outer peripheral yoke and of yoke, at the time of recording, pressing and fixing a bobbin, which is externally fitted to the internal yoke member, to be freely moved vertically with the corner of the triangle pole shape. CONSTITUTION:A bobbin 41, a coil 42 and a magnetic head 16 are integrally and vertically execute parallel linear motion and fixed to a constant position while maintaining a current constant. At the time of recording, a moving iron core 45 turns an external member 40 in one direction by turning on the current to the coil 44. When the current is turned off, the external member 40 is returned to an original position by a spring 46 and a cylindrical member 39 is turned. Accordingly, at the time of recording, permanent magnets 36 and 38, which are fixed to the cylindrical member 39, and a triangle pole-shaped yoke 37 are turned and the bobbin 41 is pressed by the corner and fixed. Then, the magnetic head 16 can be fixed in the constant position. Thus, vertical vibration caused by external disturbance, etc., is prevented and a recording track can be acquired with the satisfactory linearity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head drive device, and particularly to a magnetic head drive device in a magnetic recording/reproducing device such as a video tape recorder and a high-definition video tape recorder.

[Prior Art] FIG. 5 is a cross-sectional view showing the main parts of a rotary drum device including a conventional magnetic head drive device, and FIG. 6 is a view taken along arrows ■-■ in FIG. Lower drum, 2 is lower drum 1
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 an upper drum attached to the pedestal 4 using screws 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, and 11 is attached to the upper drum 5. A wiring board, 12 a non-rotating contact for supplying control current to the magnetic head drive device 7, 13 a rotating electrode provided on a part of the pedestal 4 so as to be in sliding contact with the contact 12, 14 a rotating contact from the electrode 13; A connecting portion 16 electrically connects to the magnetic head driving device 7 via the connecting portion 15 and the wiring board 11, and a connecting portion 16 is a magnetic head attached to the magnetic head driving device 7. A connecting portion 17. It is electrically connected to the upper transformer 10 via the wiring board 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. 19 is a position adjustment hole for adjusting the position of the magnetic head 16, and 20 is a magnetic tape that comes into sliding contact with the magnetic head 16.

FIG. 7 is Vl of FIG. 5 showing details of the magnetic head drive device.
-Vl arrow view, Figure 8 is a sectional view of Figure 7, Figure 9 is a sectional view of Figure 7.
FIG.

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.
The second yoke 24 is made of a magnetic material and is attached to the second yoke 23, and the third yoke 24 is made of a magnetic material and is attached to the second yoke 23.
Yoke 25 is a columnar second permanent magnet fixed to the third yoke 24 with the same magnetic poles as those of the first permanent magnet 22 facing each other;
Reference numeral 26 is a pole piece made of a magnetic material that is located between the second permanent magnet 25 and the first permanent magnet 22 and is fixed to either one, and 27 is a pole piece that is located between the third yoke 24 and the second yoke 23 and is made of a thin plate. A plate spring having an extension part 27a made of a magnetic material. The extension part 27a protrudes outward through windows 24a and 23a provided in the third yoke 24 and the second yoke 23, and has a magnetic head 16 at its tip. is installed.

28 is a temporary spring made of a thin plate of non-magnetic material held between the first yoke and the second yoke, 29 is a fixed member holding the temporary springs 27 and 28, respectively, and 30 has an inner periphery of the first permanent magnet 22 and A bobbin 31 is located at a position where there is a gap between the outer circumferences of the second permanent magnet 25 and the pole piece 26 and is fixed to the fixing member 29 using an adhesive 32. This is a coil made of an electric wire having a covering material wound around a bobbin 30 with a gap around the entire circumference.

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 connected to 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 25.
The total magnetic flux of traverses. Coil 3 in the above condition
1 to the contactor 12 to the electrode 13. When a current flows through the connection part 1514, the coil 31, bobbin 30, and magnetic head 16
As a unit, the magnetic head 16 is displaced in the width direction of the tape 20 and traces the magnetic recording mark with high accuracy.

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.

Figure 10 shows the vertical movement of the magnetic head caused by the force exerted on the magnetic tape by the fluctuation of the back electromotive current. - Shows a diagram showing the linearity of the link. If the magnetic head is fixed only by electrical means as described above, the effect of vibration of the magnetic head will be 2 to 3 μm.
Please refer to item 10 above to confirm that the trunk is being affected. FIG. 11 shows.

[Problem to be solved by the invention]

Conventional magnetic head drive devices are configured as described above, and in order to perform recording and reproduction using the same head, the magnetic head must be fixed at a fixed position during recording. With a fixed position, the magnetic head vibrates up and down along with the bobbin due to the reaction force when the throat enters the magnetic tape and disturbances to the device itself, resulting in problems such as poor recording track linearity and image quality deterioration. there were.

This invention was made to solve the above-mentioned problems, and the magnetic head can be fixed at a constant position without vertical vibration due to the reaction force and disturbance when entering the magnetic tape. An object of the present invention is to obtain a magnetic head drive device that can obtain excellent linearity of recording tracks.

[Means to solve the problem]

The magnetic throat drive device according to the present invention has an inner yoke member formed in the shape of a triangular prism and consisting of a yoke and first and second permanent magnets that are pivotally supported within an outer yoke, and an outer shape similar to the inner yoke member. and a bobbin that is fitted onto the inner yoke member and is movable up and down only in the axial direction, and has a rotating means for rotating the inner yoke member, and the inner yoke member is rotated using the rotating means during recording. The bobbin, which can only be moved vertically, is pressed and fixed by the corner of a triangular prism-shaped internal yoke member, thereby fixing the magnetic head at a fixed position.

[Effect]

The magnetic head drive device according to the present invention rotates an internal yoke member consisting of a yoke and triangular prism-shaped first and second permanent magnets pivotally supported within a yoke during recording, so that the internal yoke member is externally The fitted bobbin, which can only move up and down, is pressed and fixed by the triangular prism-shaped corner of the internal yoke member, and the magnetic head can be fixed in a fixed position, so there is no reaction force or disturbance when the magnetic tape enters during recording. A recording track with excellent linearity can be obtained without being affected by

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a magnetic head drive device according to an embodiment of the present invention, and FIG. 2 is a plan view of the magnetic head drive device according to an embodiment of the present invention, showing a rotating means. Figure 3 is the first
FIG. 4, which is a sectional view taken along line 1--2 in the figure, is a diagram showing the operation of the present invention.

In FIG. 1, 33 is a first yoke made of a magnetic material, and has a concave portion 33a formed by rotating a triangular shape as shown in FIG. 39 is a cylindrical member that penetrates the first yoke 33 and is made of a rotatable non-magnetic material; 40 is a member for rotating the cylindrical member 39 in a direction perpendicular to the central axis of the cylindrical member 39; 36 is a member that is attached to the cylindrical member 39; fixed and first
A triangular prism-shaped first permanent magnet in contact with the yoke 33, 34 is the first yoke 3 having a convex portion 34a in a part of the inside.
A second yoke made of magnetic material attached to 1.3
A third yoke 5 made of a magnetic material is attached to the second yoke 34, and has a recess 35a having the same shape as the recess 33a and a protrusion 35b at the center of the recess 35a. 38 has the same magnetic pole as the first permanent magnet 36, has the same shape, and faces the third permanent magnet 36.
a triangular prism-shaped second permanent magnet in contact with the yoke 35;
A recess 38a is provided on the contact surface of the third yaw lever 35. 37 is a triangular prism-shaped yoke made of magnetic material arranged in the same shape between the first permanent magnet 36 and the second permanent magnet 3, and 41 is the first permanent magnet 36 as shown in FIG.
．． Second permanent magnet 38. A triangular prism-shaped bobbin having a gap between it and the outer periphery of the triangular prism-shaped yoke 37; 42 is the bobbin 4;
A coil consisting of an electric wire having a sheath wound around it,
There is a gap between the second yoke 34 and the entire circumference. Here, the central axis of the cylindrical member 39 and the third yoke 3
The center axis of the convex portion 35 of No. 5 coincides with the center axis of the bobbin, and is configured to rotate around this center axis, and this center axis is also configured to coincide with the center axis of the bobbin.

In Fig. 2, 43 is a fixed core, 44 is a coil, and 45 is a fixed core.
is a movable iron core. 46 is the outer member 40 of the movable core 45
It is a spring attached to the opposite side.

Next, the operation will be explained.

The bobbin 41, coil 42, and magnetic head 16 move vertically and linearly in unison in the same way as in the conventional principle, and can be fixed at a fixed position by keeping the current constant.

In FIG. 2, during recording, the movable core 45 rotates the external member 40 in one direction by turning on the current to the coil 44. O
When set to FF, the spring 46 returns the external member 40 to its original position. When the external member 40 rotates, the cylindrical member 39 also rotates. The above-mentioned rotating operation is performed by a rotating means 47, and the rotating means 47 causes the first
Permanent magnet 36 - triangular prism yoke 37. The second permanent magnet rotates in the H direction as shown in FIG. 4, contacts the bobbin 41, and presses its corner to fix the bobbin 41 and fix the magnetic head 16 at a fixed position. Therefore, it is possible to obtain a recording track with excellent linearity during recording without vertical vibration due to the influence of external disturbances or the like.

Although an electromagnet was used as the rotation means for rotation,
Any mechanism may be used as long as it rotates.

Further, in the above embodiment, the internal yoke member is formed in the shape of a triangular prism, but it may be formed in another polygonal prism shape as long as it can be held down by rotation and the electromagnetic force is not lost. It has a similar effect.

〔Effect of the invention〕

As described above, according to the magnetic head drive device in the magnetic recording and reproducing apparatus according to the present invention, the first permanent magnet and the second permanent magnet each have a triangular prism shape and are disposed within the outer circumferential yoke and are rotatably supported. an internal yoke member formed from a magnet and a yoke made of a magnetic material sandwiched between the permanent magnets; and an axially extending inner yoke member that is fitted onto the inner yoke member and has an external shape similar to the inner yoke member. A magnetic head is attached to the bobbin so as to be located outside the outer circumferential yoke via a leaf spring, and a rotating means for rotating the member is provided. Since the internal yoke member is rotated by the moving means and pressed against the bobbin, and the magnetic head is fixed in a fixed position, it is not affected by the reaction force and disturbance when the magnetic tape enters during recording. A recording track with excellent linearity can be obtained, and image quality deterioration can be prevented.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing a magnetic head drive device according to an embodiment of the present invention, FIG. 2 is a plan view of a magnetic head drive device according to an embodiment of the present invention, and FIG. 4 is a sectional view showing the operation of the present invention during rotation, FIG. 5 is a sectional view showing the main parts of a rotating drum device including a conventional magnetic head drive device, and FIG. ■- in Figure 5
■An arrow view, FIG. 7 is a Vl-Vl arrow view of FIG. 5 showing details of the magnetic head drive device, FIG. 8 is a sectional view of FIG. 7, FIG. 9 is a side view of FIG. 7, Figure 10 shows the vertical movement of a conventional magnetic head caused by the force exerted on the magnetic tape by the fluctuation of the back electromotive current, and Figure 11 shows the recording caused only by the vibration of the conventional magnetic head during recording. FIG. 3 is a diagram showing the linearity of a track. 1 is a lower drum, 2 is a bearing, 3 is a rotating shaft, 4 is a pedestal, 5 is an upper drum, 6 is a screw, 7 is a magnetic head drive device, 8 is a screw, 9 is a lower transformer, 10 is an upper transformer, 11 is a A wiring board, 12 a contact, 13 an electrode, 14 a connection part, 16 a magnetic head, 17 a connection part, 18 a recess, 19 a position adjustment hole, 20 a magnetic tape, 21 a first yoke, 22 is a first permanent magnet, 23 is a second yoke, 23a is a convex portion, 2
4 is the third yoke, 24a is the window, 25 is the second permanent magnet, 2
6 is a pole piece, 27 is a leaf spring, 27a is a leaf spring extension, 28 is a leaf spring, 29 is a fixing member, 30 is a bobbin, 3
1 is a coil, 32 is an adhesive, 33 is a first yoke, 33a
, 35a is a concave portion created by rotating a triangular shape, 3
4 is a second yoke having a convex portion 34a in a part of the inside, and 35 is a concave portion 35a and a convex portion 35b at the center of the concave portion 35a.
36 is a triangular prism-shaped first permanent magnet, 37 is a triangular prism-shaped yoke, and 38 is a third yoke 35
39 is a cylindrical member, 40 is a member for rotating the cylindrical member 39, 41 is a triangular prism-shaped bobbin, and 42 is wound around the bobbin 41. 43 is a fixed core, 44 is a coil, 45 is a movable core, 46 is a spring, and 47 is a rotating means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A magnetic head drive device for a magnetic recording and reproducing device, which is composed of a first permanent magnet, a second permanent magnet, and a yoke made of a magnetic material sandwiched between the two permanent magnets, and is arranged within an outer yoke and rotates. an internal yoke member having a polygonal columnar shape that is movably supported; a bobbin that is fitted onto the above member and has an external shape similar to the above member and is movable up and down only in the axial direction; A magnetic head attached to the bobbin so as to be located outside the outer circumferential yoke, and a rotating means for rotating the inner yoke member, and during recording, the rotating means rotates the inner yoke member. A magnetic head drive device characterized in that the position of the magnetic head is fixed by applying an edge to the bobbin.