JPH0214421A - Rotary drum device - Google Patents

Abstract

PURPOSE:To shorten the locating time of a head and to reduce even the adjustment allowance of the locating by composing a yoke fitted after a spring plate to fix the head of two members. CONSTITUTION:A yoke 47 houses and holds plate springs 41 and 42, a cylinder coil 44, a coil bobbin 43, a part of column permanent magnets 45 and a pole piece 46a, simultaneously, it is divided for facilitating a housing assembling, and it is composed of parts 47a-47c. Further, the yoke 47a is divided into 47d and 47e. For such a reason, the plate spring 41 to fix a head 5 is located and fixed to the yoke 47d, and thereafter, the yoke 47d can be assembled to the yoke 47b. Thus, the adjusting time at the time of locating the head to an upper drum can be shortened, and the adjustment allowance can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field J] This invention is applicable to, for example, a video tape recorder (hereinafter referred to as VT).
(abbreviated as "R") was developed specifically to improve the playback quality of VTRs.The video head mounted on a rotating drum was made movable in the width direction of the magnetic tape to faithfully trace the magnetic recording traces. The present invention relates to a rotating drum device configured to rotate.

[Conventional technology]

FIG. 4 is a cross-sectional view showing the main parts of the rotating drum device shown in, for example, Japanese Patent Application No. 62-3713, FIG. 5 is a plan view thereof, FIG. 6 is a detailed plan view of the head drive section, and FIG. 7 is a sectional view of FIG. 6, and FIG. 8 is a front view of FIG.

Now, in Figures 4 and 5, (4a) is the head (
5) is fixed at the tip and is a drive unit for moving the head (5) in the width direction of the tape. Reference numeral 50 indicates a recess provided in a part of the upper drum (3) to accommodate the drive part (4a), and is formed to have a large circumference in order to adjust the position of the drive part (4a). The head is positioned using the position adjustment hole (51) and the yoke (47) is fixed with the screw (48).
Fix it with. Note that (14) is a non-rotating contact for supplying control current to the drive unit (4a), and (15) is a rotating contact provided on a part of the pedestal (9) so as to be in sliding contact with the contact (14). The electrode (16) is connected from the electrode (15) to the connection part (
12) and the wiring board (11) to electrically connect to the drive unit (4a). The head (5) has a connecting part (10
), the wiring board (11), and the connecting portion (12), and are electrically connected to the upper t-rance (7). .

Figures 6, 7, 8 and 9 show the drive section (4a)
(41) is a non-magnetic plate spring with a head (5) attached to the tip, (43) is a coil bobbin (44) attached to the plate spring (41),
(3) is a cylindrical coil for driving wound around the coil bobbin (43), and (42) is a leaf spring that supports the coil bobbin (43) and deforms together with the leaf spring (41) to enable linear movement of the coil bobbin (43). 45) is a cylindrical permanent magnet, (46) is a cylindrical permanent magnet arranged with the same magnetic poles as those of the cylindrical permanent magnet (45) facing each other, and (46a) is a pair of cylindrical permanent magnets (45), (46). ), the ferromagnetic pole piece (47) is a yoke. This yoke (47)
are leaf springs (41), (42), cylindrical coil (44),
Coil bobbin (43), pair of cylindrical permanent magnets (45)
(46) and pole piece (46a), and is divided into sections for easy storage and assembly.
47a), (47b), and (47c), (
48a) is a screw hole for attaching and fixing the yoke (47) to the upper drum. (49) is a window provided in a part of the yoke (47). A head (5) projects through this window (49) and is arranged on the upper drum in sliding contact with the tape (13). The cylindrical coil (44) and coil bobbin (43) are connected to a pair of cylindrical permanent magnets (
45), (46) and the annular gap formed between the pole piece (46a) and the yoke so as to be movable up and down. Further, the leaf spring (41) is held between parts (47a) and (47b) of the yoke (47), and the leaf spring (42) is held between parts (47b) and (47c). .

Referring to FIG. 6, the magnet (45) generates a magnetic flux (D
) are generated radially from the pole piece (46a) toward the yoke. Similarly, the magnet (46) is part (47b)
, (47c) create a closed magnetic path in the opposite direction to generate magnetic flux (E), and both magnetic fluxes (D) and (E) cross the annular gap in the same direction. Thus, the cylindrical coil (44
) is crossed by the total magnetic flux of magnets (45) and (46). From the contactor (14) to the electrode (15) to the coil (44),
When a current is passed through the connections (12) and (16), the coil (44), coil bobbin (43), and head (5) move vertically in a parallel straight line as one. Thus the head (
5) is displaced in the tape width direction.

[Problems to be Solved by the Invention] Since the conventional rotating drum device is configured as described above, the head drive section has a yoke (
47c), permanent magnet (46), pole piece (46a)
, leaf spring (42), bobbin (43), coil (44),
After assembling the yoke (47b), the leaf spring (41) to which the head (5) is fixed is fixed to the yoke (47b),
Finally, since the yoke (47a) to which the permanent magnet (45) is fixed is assembled, it is difficult to accurately position the head (5) and the yoke (47a).
) is attached to the upper drum (3) by the yoke (47a), the head (5) is positioned relative to the upper drum (3) for the first time, so it takes time to adjust the head (5) and the upper drum and yoke (47a).
It was also necessary to increase the adjustment margin for 47a).

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a rotating drum device that can shorten the time for positioning the head with respect to the upper drum and reduce the adjustment margin.

[Means for Solving the Problems 1] In the rotating drum device according to the present invention, the yoke (47a) is divided into two pieces, and the assembly procedure is changed.

[Function] The rotating drum device according to the present invention includes a yoke (47a)
By dividing the head (5) and the yoke (47a) into two pieces, the positioning of the head (5) and the yoke (47a) becomes easier, the time for adjusting the head (5) and the upper drum (3) is shortened, and the adjustment margin is also reduced.

[Embodiment J] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
The figures are detailed sectional views of the head drive section of the rotating drum device according to the present invention, FIG. 2 is a plan view, and FIG. 3 is a front view. In these figures, (1) to (51) indicate the same members as in the conventional device, but the yoke (47a) in the conventional device is divided into two pieces, (47d) and (47e) in the present invention. ing.

The operation of the head drive unit in the rotating drum device of the present invention is exactly the same as that of the conventional device, but the assembly procedure is different. In particular, in the conventional head drive unit, the plate spring (41) having the magnetic head (5) is connected to the yoke (47b).
) and the coil bobbin (43), the yoke (47a) having the cylindrical permanent magnet (45) is attached to the yoke (47b) so that the cylindrical permanent magnet (45) fits into the coil bobbin (43). However, in the present invention, after positioning and fixing the plate spring (41) having the magnetic head (5) to the yoke (47d), this yoke (47d) is attached to the yoke (47b). At this time, the inner periphery of the leaf spring (41) is fitted into the coil bobbin (43), and its center positioning is performed using a jig or the like through a hole in the yoke (47d). Thus, the leaf spring (41
) is also the coil bobbin (43) for the yoke (47d).
It is also actively positioned. Finally, the yoke (47e) having the cylindrical permanent magnet (45) is connected to the yoke (47e).
The hole 7d) is closed to complete the magnetic path of the magnetic flux (D).

The yoke (47a) of the conventional device is replaced with the yoke (47d) of the present invention.
) and (47e), the head (5)
After positioning and fixing the plate spring (41) to the yoke (47d), the yoke (47d) can be assembled to the yoke (47b), reducing the adjustment time when positioning the head (5) relative to the upper drum. The margin for shortening and adjustment can be reduced.

[Effect of the invention 1 As described above, according to the present invention, the yoke that is attached after the plate spring to which the head is fixed is composed of two members, so that the time for positioning the head is shortened and the margin for positioning adjustment is also reduced. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a head drive unit showing an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a front view, and FIG. 4 is a sectional view showing the main parts of a conventional rotating drum device. , Fig. 5 is a plan view thereof, Fig. 6 is a detailed plan view of the head drive section, Fig. 7 is a plan view of Fig. 6, Fig. 8 is a front view of Fig. 6, and Fig. 9 is a plan view of the leaf spring. It is a detailed view. In the figure, (4a) is a head drive unit, (5) is a magnetic head, (41), (42) are leaf springs, (43) is a bobbin, (44) is a coil, and (45). (46) is a cylindrical permanent magnet, (46a) is a ball bee,
The yoke portion (49) in (47a) to (47e) is a window. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent: Masu Oiwa, patent attorney

Claims (1)

[Claims] (1) A rotating drum device that moves the head in the width direction of the tape so that the head trajectory during recording matches the head trajectory during playback even under any tape feed speed. A fixed magnetic pole piece, a permanent magnet placed across this pole piece with the same polarity facing the pole piece, and each of the above-mentioned permanent magnets placed with a gap around this pole piece. a yoke made of a magnetic material so that two lines of magnetic force from the magnet pass in the same direction across the gap and form two closed magnetic paths in opposite directions; and a yoke disposed within the gap so as to cross the lines of magnetic force; and a coil supported movably in a direction perpendicular to the magnetic lines of force, the head being moved in accordance with the movement of the coil when the coil is energized, and the coil has a substantially concentric circular shape. One or more discontinuous grooves are provided, a part of the outer periphery or almost the entire periphery is held by a fixing member, and the innermost periphery is held by a coil or a bobbin of the coil, or a part of the inner periphery or a circular or nearly circular shape formed of two or more non-magnetic or non-magnetic materials, which is entirely held by a fixed member and configured to hold a coil or coil bobbin on the outermost periphery. In a structure in which the yoke is supported by a spring and is divided during assembly, the divided yoke, which fixes the structure to the upper drum, is a plate that supports the magnetic head. A rotating drum device characterized in that the yoke is further divided into two parts to have holes for positioning a spring.