JPH05109035A - Rotary drum device - Google Patents

Abstract

PURPOSE:To mount a head drive part on an upper drum so that the azimuthal angle of a magnetic head coincides with a prescribed value in a rotary drum device wherein the magnetic head is moved in the width direction of a tape and a recording locus is traced accurately even at an arbitrary tape feed speed. CONSTITUTION:When the member of the mounting part onto an upper drum of a head drive part is cut by the portion of a discrepancy angle theta'' with reference to the prescribed value of an azimuthal angle so that it is matched to the azimuthal angle, a cutting edge can perform a cutting operation without interfering with other members, and a relief shape beta is formed in a core. The mounting part onto the upper drum of the head drive part is formed of a material whose cutting property is good so that it can be cut easily. It is possible to obtain an optimum replay signal in which a cross talk from other recording signals is small and it is possible to enhance the yield of the production of the title device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video tape recorder (hereinafter abbreviated as VTR) for improving image quality.
The present invention relates to a rotary magnetic head device that makes a video head movable in the width direction of a magnetic tape and faithfully traces a magnetic recording trace.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a main part of a conventional rotary drum device (for example, Japanese Patent Application No. 62-198468), and FIG. 7 is a bottom view thereof. In these figures, 1 is a rotary shaft, 2 is a lower drum, 3 is a rotating upper drum, and 4a is a head for fixing the magnetic head 5 at its tip and for moving the magnetic head 5 in the width direction of the magnetic tape 13. It is a drive unit. 53 is the upper drum 3 for accommodating the head drive unit 4a.
Is a recess provided in a part of the above, and is formed to be slightly larger in order to adjust the position of the head drive section 4a. The core 47 is positioned using the mounting position adjusting hole 54, and the core 47 is fixed with the screw 48. Reference numeral 14 is a non-rotating contactor for supplying a control current to the head drive unit 4a, 15 is a rotating electrode provided in a part of the pedestal 9 so as to make sliding contact with the contactor 14, and 16 is a connecting portion from the electrode 15 12 and wiring board 1
1 is a connection portion that is electrically connected to the head drive portion 4a via 1. The magnetic head 5 is electrically connected to the upper transformer 7 via the connecting portion 10, the wiring board 11, and the connecting portion 12, and further magnetically connected to the lower transformer 8.

FIGS. 8, 9 and 10 show the head drive section 4a in detail, FIG. 8 is a detailed sectional view of the head drive section used in the rotary drum device of FIG. 6, and FIG. 9 is a front view thereof. FIG. 10 is a bottom view thereof. In these figures, 4
Reference numeral 1 is a non-magnetic plate spring having a magnetic head 5 attached to the tip thereof, and 51 is a flexible substrate arranged below the plate spring 41. Signals from the magnetic head 5 are sent to a connecting portion 10 (see FIG. 7). It has a conductor for taking out. Reference numeral 43 is a coil bobbin attached to the leaf spring 41, 44 is a driving cylindrical coil wound around the coil bobbin 43, and 42 is a coil bobbin 43 for supporting the coil bobbin 43 and deforming together with the leaf spring 41 so that the coil bobbin 43 can move linearly. The plate spring 50 is a flexible substrate disposed below the plate spring 42, and has a conductor for passing a drive current from the connecting portion 16 (see FIG. 7) to the cylindrical coil 44. Reference numeral 45 is a cylindrical permanent magnet, 46 is a cylindrical permanent magnet in which the same magnetic poles as the cylindrical permanent magnet 45 are arranged so as to face each other, and 46a is a ferromagnetic material provided between a pair of cylindrical permanent magnets 45, 46. The center pole and 47 are cores. The core 47 includes leaf springs 41 and 42, a cylindrical coil 44, a coil bobbin 4
3, a pair of cylindrical permanent magnets 45 and 46 and a center pole 46a are housed and held, and are divided into parts 47a, 47b and 47c so as to be easily housed and assembled. Reference numeral 48a is a screw hole for attaching and fixing the core 47 to the upper drum. This screw hole 48a is the core 4
It is provided on the drive unit mounting ear 48b of the seventh portion 47c. Reference numeral 49 is a window provided in a part of the core 47. The magnetic head 5 projects through the window 49 and is arranged on the upper drum 3 so as to come into sliding contact with the tape 13. The cylindrical coil 44 and the coil bobbin 43 are composed of a pair of cylindrical permanent magnets 45 and 46, a center pole 46a and a core 4.
It is arranged movably up and down in an annular gap formed between the upper and lower ends. Further, the leaf spring 42 is a portion 47 a of the core 47.
And 47b, and the leaf spring 41 is sandwiched between the portions 47b and 47c. Referring to FIG. 8, the permanent magnet 46 radially generates a magnetic flux D from the center pole 46a toward the core due to a closed magnetic circuit formed by the portions 47a and 47b of the core 47. Similarly, the permanent magnet 45 has a portion 47.
b and 47c form a closed magnetic path in the opposite direction to generate a magnetic flux E, and the magnetic fluxes D and E both traverse the annular gap in the same direction. Thus, the cylindrical coil 44 has magnets 45 and 4
The total magnetic flux of 6 crosses. When an electric current is applied to the coil 44 from the contactor 14 through the electrode 15 and the connecting portions 12 and 16, the coil 44, the coil bobbin 43 and the magnetic head 5 integrally move vertically in a straight line. Thus the magnetic head 5
Is displaced in the tape width direction. Reference numeral 60 is a shield cover.

[0004]

Since the conventional rotary drum device is constructed as described above, the mounting ear 48b of the head driving portion 4a is arranged in the direction of the azimuth angle of the head with respect to the mounting surface of the upper drum 3. Since it is difficult to attach it with high accuracy, when assembled as a rotary drum device, the azimuth angle of the head is not within the tolerance of the design value with respect to the rotation trajectory, and the recording signal cannot be read. However, there is a problem that crosstalk from other recording signals is easily received.

The present invention has been made to solve the above problems.

[0006]

In the rotary drum device according to the present invention, the mounting ears of the head drive section are cut so that the azimuth angle of the head fits within the design tolerance. Therefore, a relief shape is provided in the core so that the cutting edge can cut the ear portion without interfering with other members. Further, in the present invention, the mounting ear of the core is made of a material having a good cutting property to facilitate the cutting processing of the mounting ear adapted to the azimuth angle.

[0007]

In the rotary drum device according to the present invention, since the azimuth angle can be adjusted when the upper drum is attached, it is possible to obtain an optimum reproduction signal with less azimuth loss and less crosstalk.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The configuration of the entire rotary drum device is the same as that of the conventional example, and only the core portion 47c of the core 47 of the head drive unit 4a is different. This is shown in cross section in FIG. FIG. 2 is a diagram showing a state in which the head drive unit 4a is attached to the upper drum 3. FIG. 3 is a view for explaining a state in which actual cutting is performed in order to adjust the drive portion mounting ear 48b of the core portion 47c shown in FIG. 1 by θ ″ degrees indicated by the shaded portions. Is adjusted after the head drive unit is assembled, the head drive unit 4a and the cutting blade 7 are adjusted.
It requires some clearance α with 0. Therefore, the core 47 has a relief shape indicated by β so that the clearance α can be taken.
It is provided in. FIG. 5 is a diagram for explaining a mounting state of the magnetic head 5. The x-axis of FIG. 5 is the direction in which the upper drum rotates, that is, the direction of travel of the recording locus, and the y-axis is the coordinates orthogonal thereto. Now, if the azimuth angle of the magnetic head 5 assembled to the rotary drum device is θ degrees with respect to the y-axis, in order to adjust this to the design value θ ′ degree, only θ ″ degrees are required. It is sufficient to scrape off the shaded part of 1.

The core portion 47c needs to be a magnetic material for the mechanism of the head drive portion 4a, but it is not necessary for the portion to be cut (that is, the mounting ear 48b), so that the cutting can be performed easily and accurately. The core portion 47c having a double structure as shown in FIG. 4 can be used so that it can be cut.

The shaded portion shown in FIG. 4 is a magnetic material, and a material having good cutting properties is formed by inserting a portion of the magnetic material into the portion other than the magnetic material. Further, as the material having good machinability, a material having properties such as brass and free-cutting aluminum that are non-magnetic and hardly rust is desirable. Alternatively, a material for an alumina-based sintered body, which does not cause material chipping due to cutting or polishing as described in JP-A-3-119508, may be used. The material of the sintered body also has an advantage that it is easy to insert the magnetic material portion for molding.

[0011]

As described above, according to the present invention, the azimuth angle of the head can be adjusted to the design value by cutting the mounting ear portion of the head drive unit, so that the optimum crosstalk is minimized. It becomes possible to obtain a reproduction signal, and it is possible to use it as a good product by cutting the head drive unit that was defective due to the deviation of the head azimuth angle tolerance due to the assembly error of the head drive unit in the past, at the mounting ear. There is an effect that it also leads to an improvement in yield.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a core portion having an ear for mounting a core of a head driving portion, which is a main portion of a rotary drum device of the present invention, to an upper drum.

FIG. 2 is a diagram showing a state in which a head drive unit including a core having the attachment body of FIG. 1 is attached to an upper drum.

FIG. 3 is a diagram for explaining a state when the diagonally shaded portion shown in FIG. 1 is actually cut.

FIG. 4 is a side view showing a core portion of a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an azimuth angle of a magnetic head in a rotary drum device.

FIG. 6 is a diagram showing the periphery of a head drive unit of a conventional rotary drum device.

FIG. 7 is a bottom view of the vicinity of the head drive unit shown in FIG.

FIG. 8 is a cross-sectional view illustrating details of the head drive unit illustrated in FIG.

9 is a front view of the head drive unit in FIG.

FIG. 10 is a bottom view of the head drive unit in FIG.

[Explanation of symbols]

 3 Upper drum 4a Head drive part 5 Magnetic head 41 Leaf spring 47 Core 47c Core part 48b Drive part mounting ear 70 Cutting tool β Relief shape

Claims (2)

[Claims] 1. A rotary drum device in which a head is moved in a width direction of a tape so that a locus of the head during recording and a locus of head during reproduction coincide with each other even at an arbitrary tape feeding speed, and a permanent magnet. And a core of a magnetic body that forms a magnetic path of magnetic force lines from the permanent magnet, and a coil that is arranged in the gap so as to cross the magnetic force lines and is movably supported in a direction orthogonal to the magnetic force lines, Two or more of the coils are partially held by a fixing member and the coil or the bobbin of the coil is held so that the head moves in accordance with the movement of the coil due to the energization of the coil. In a rotating drum device supported by a spring formed of a non-magnetic material or a material having a property similar thereto, by cutting an attachment portion of the core to the upper drum, When matching the azimuth angle of the head to a specified value, a relief shape is provided on the core so that the attachment part of the core to the upper drum can be cut without the cutting blade interfering with other members. Characteristic rotary drum device. 2. The rotary drum device according to claim 1, wherein a mounting portion of the core to the upper drum is a double-structured core made of a material having a good cutting property.