JPH0540925A - Head driving device and its manufacture - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a head drive device that does not interfere with the vertical movement of the head and has good linearity in vertical drive characteristics. [Structure] A conductor forming part of a head signal line and a part of a head drive coil drive signal line is formed by an electroforming method, and the conductor carries a head and holds upper and lower ends of a coil bobbin. The leaf springs 41 and 42 were attached to the surface to form a part of the wiring pattern. [Effect] Since the flexible substrate used for the conventional wiring is eliminated, it is possible to prevent the flexible substrate from interfering with the coil bobbin or the core when the head is vertically driven, and the leaf springs 41 and 42 have almost no difference in spring constant in the vertical direction. Since it is eliminated, the linearity of operation is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a video tape recorder (hereinafter referred to as "VTR"), and more specifically, a head drive for moving a video head in a width direction of a magnetic tape provided on a rotating drum. The present invention relates to a device and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing a main part of a conventional rotary drum device (for example, Japanese Patent Application No. 62-198468), and FIG. 6 is a partially enlarged bottom view thereof. In these figures, 1 is a rotary shaft, 2 is a lower drum, 3 is a rotating upper drum, 4 is a voice coil type head driving device, 5 is a video head, and the head driving device 4 is a part of the upper drum 3. It is mounted with a screw 48 in the recess 53 provided.

Reference numeral 14 is a contactor for supplying a control current to the head drive device 4, and reference numeral 15 is a rotating electrode, which is in sliding contact with the contactor 14. At 10, 12, 16 connection portions, the rotary electrode 15 is electrically connected to the head drive device 4 via the connection portion 12 and the wiring board 11. The video head 5 is electrically connected to the upper transformer 7 and further magnetically connected to the lower transformer 8 via the connecting portion 10, the wiring board 11, and the connecting portion 12.

FIG. 7 is a longitudinal sectional view of the head drive device 4, FIG. 8 is a front view thereof, and FIG. 9 is a bottom view thereof. In these figures, 41 and 42 are leaf springs formed of a non-magnetic material, and the video head 5 is attached to the tip thereof.
Reference numerals 50 and 51 denote flexible substrates, each of which has a conductor, and the flexible substrate 50 is disposed below the leaf spring 42, and the flexible substrate 51 is disposed below the leaf spring 41.

Reference numeral 43 is a coil bobbin, and 44 is a driving coil wound around the coil bobbin 43.
2 supports the upper and lower ends of the coil bobbin 43, and the leaf springs 41,
The deformation of 42 holds the coil bobbin 43 so that it can move linearly.

FIG. 10 is a plan view showing the leaf spring 41 and the flexible substrate 51, FIG. 11 is an exploded side view thereof, and FIG. 12 is a plan view of the leaf spring 42 and the flexible substrate 50.
66 is a land.

45 and 46 are cylindrical permanent magnets, and the permanent magnets 45 and 46 are arranged with the same magnetic poles facing each other. 46a is a center ball made of a ferromagnetic material provided between the permanent magnets 45, 46, and 47 is a core. And center ball 4
6a is housed and held, and is composed of three parts 47a, 47b, 47c for easy housing and assembly.

Reference numeral 48a is a screw hole for attaching the core 47 to the upper drum 3, and the screw hole 48a is provided in the drive portion attaching ear 48b of the core 47c. 49 is core 4
The video head 5 projects through the window 49 in a part of the window 7 and is arranged on the upper drum 3 so as to be in sliding contact with the magnetic tape 13.

The coil 44 and the coil bobbin 4
3 is a permanent magnet 45, 46 and a center ball 46a
And a core 47, and is movably arranged vertically in an annular gap formed between the core 47 and the core 47. In addition, the leaf spring 42 is the core 4
It is sandwiched between 7a and 47b, and the leaf spring 41 forms the core 47.
It is sandwiched between b and 47c.

Next, the operation of the head drive device 4 will be described. The permanent magnet 46 forms a closed magnetic path that passes through the cores 47a and 47b, and the magnetic flux D is radially generated from the center ball 46a toward the core. Similarly, the permanent magnet 45
Generates a magnetic flux E by forming a closed magnetic circuit in the opposite direction passing through the cores 47b and 47c, and the magnetic fluxes D and E both traverse the annular gap in the same direction and thus the coil 44.
The total magnetic flux of the permanent magnets 45 and 46 traverses.

The coil 44 is attached to the rotating electrode 1 from the contactor 14.
5, when a current is passed through the connecting portions 12 and 16, the coil 4
4, the coil bobbin 43 and the video head 5 integrally move vertically and linearly in parallel, and the video head 5 is displaced in the width direction of the magnetic tape. Reference numeral 60 is a shield cover.

[0012]

Since the conventional head driving device is constructed as described above, the flexible substrates 50 and 51 interfere with the leaf springs 41 and 42 or the core 7 when the head is driven. However, there is a problem that smooth head drive can be prevented. Further, since the flexible substrates 41 and 42 act like spring materials and act so that the spring constant changes in the vertical direction when the head is driven, there is a problem that the linearity of the driving characteristics is impaired.

Further, since the number of parts is large, the assembling workability is poor, and there is a problem in manufacturing that causes an increase in defective rate.

The present invention has been made to solve the above problems, and the vertical movement of the head moves smoothly without interference, and there is almost no difference between the upper and lower spring constants within a required vertical movable range. It is an object of the present invention to obtain a head drive device that can be manufactured and a method of manufacturing a head drive device that is easy to assemble.

[0015]

According to another aspect of the present invention, there is provided a head driving device, wherein a conductor forming a signal lead-out line of a magnetic head and a drive signal lead-out line to a driving coil holds the coil bobbin. Leaf springs 41, 42
It is characterized by being attached to the surface of.

According to the second aspect of the present invention, a conductor formed in a predetermined pattern by an electroforming method is attached to the surfaces of the leaf springs 41 and 42 to form wiring to the head and the driving coil. It is characterized by the point.

[0017]

According to the invention of claim 1, the signal lead-out line of the magnetic head and the drive signal lead-out line of the head driving coil are attached to the surfaces of the leaf springs 41 and 42 with the conductors constituting the lead-out lines attached. Therefore, the leader wire does not interfere with the coil bobbin or the core when the magnetic head is driven up and down, and the change of the leaf spring constant in the up and down direction is almost eliminated.

According to the second aspect of the invention, the leaf springs 41, 4 are provided.
Since a conductor formed by electroforming is attached to the surface of No. 2 to form a lead line, a thin conductor having an accurate shape can be easily manufactured, the number of parts is reduced, and assembly is facilitated.

[0019]

1 is a vertical sectional view of an embodiment of the invention of claim 1, FIG. 2 is a vertical sectional view showing an assembled state of a coil bobbin and a leaf spring, and FIG. 3 (a) is a line 2a-a. Plan view from the arrow, FIG.
2B is a plan view taken along the line 2b-b in FIG. 2, and FIG.
It is a cross-sectional view of (b).

In FIGS. 3B and 3C, 69 is an insulating film, and 62 is a conductor formed in a predetermined pattern by an electroforming method. As shown in c), it is attached to the surface of the leaf spring 41, lands 61 and 63 are formed at both ends, and the lead wire of the video head 5 is connected to the land 61, and the land 63 is connected to the land 63. A lead wire from the outside is connected.

The leaf spring 42 shown in FIG.
Similar to the leaf spring 41 shown in (b) and (c), the conductor 6
5 is attached to the surface of the leaf spring 42 via an insulating film, and lands 66 and 67 are formed at both ends thereof.
The lead wire of the coil 44 is connected to the land 66, and the lead wire from the outside is connected to the land 67.

FIG. 4 is a plan view of a leaf spring 41 according to another embodiment of the first aspect of the invention, showing an example in which the composite heads 5a and 5b are mounted. In this embodiment, two conductors 62
a and 62b are formed so as to be symmetrical with each other, and the leaf spring 4 is formed.
61a, 61b, 63 attached on the surface of No. 1
a and 63b are lands.

In the above embodiment, the conductors 62 and 65 are used.
Was pasted on the surface of the leaf springs 41, 42 formed of a non-magnetic metal material via the insulating film 69.
When is made of an insulating material such as synthetic resin, the insulating film 69 is unnecessary.

Next, the advantages obtained by manufacturing the conductors 62 and 65 by electroforming will be described. The conductors 62 and 65 must have a precise shape that follows the shape of the leaf springs 41 and 42, and must be extremely thin so that the spring constants of the leaf springs 41 and 42 are less affected. ..

[0025] This, for example, when the cross-sectional shape of the conductor to be a rectangular, its moment of inertia I is, I = bk ^3/12 (although b is the width, h is the height) Sadamari, the thickness This is because the third power is effective. According to the electroforming method, it is possible to easily manufacture a conductor that satisfies such requirements. In addition, the conductors 41 and 42 are connected to the leaf spring 4
Since the leader line can be formed by simply sticking it on the surfaces of Nos. 1 and 42, the assembling work becomes easy.

[0026]

According to the first aspect of the present invention, the conductor is attached to the surface of the leaf spring which holds the coil bobbin of the head driving device to form the lead wire. Since the substrate can be removed, interference does not occur when the head is driven, and the difference between the upper and lower spring constants of the leaf spring is almost eliminated, so that the linearity of the driving characteristic is improved.

According to the second aspect of the present invention, since the conductor is manufactured by the electroforming method, it is possible to easily and accurately manufacture a conductor having an extremely thin desired pattern. Therefore, it is possible to improve the characteristics of the head drive device. This has the effect of reducing costs.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a head drive device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing the structures of a coil bobbin and a leaf spring of this embodiment.

3 is a plan view taken along the line aa and line bb of FIG. 2 and a cross-sectional view of a leaf spring 41. FIG.

FIG. 4 is a plan view of a leaf spring 41 according to another embodiment of the present invention.

FIG. 5 is a vertical sectional view showing a main part of a conventional rotary drum device.

FIG. 6 is a partially enlarged bottom view showing a mounting portion of this conventional head drive device.

FIG. 7 is a vertical cross-sectional view of the conventional head drive device.

FIG. 8 is a front view of the head drive device.

FIG. 9 is a bottom view of the head drive device.

FIG. 10 is a plan view showing a leaf spring 41 for carrying a head and a flexible substrate of this conventional example.

11 is an exploded side view of the leaf spring and the flexible substrate of FIG.

FIG. 12 is a leaf spring 4 for carrying a coil bobbin of this conventional example.
It is a top view showing 2 and a flexible substrate.

[Explanation of symbols]

 4 Head Drive Device 5 Video Head 41, 42 Leaf Spring 43 Coil Bobbin 44 Coil 45, 46 Cylindrical Permanent Magnet 46a Center Pole 47 Yoke 61, 63, 65, 66 Land 62, 65 Conductor 69 Insulating Film

Claims (2)

[Claims] 1. A voice coil type head driving device provided in a rotating drum device for moving a magnetic head in a width direction of a magnetic tape, wherein the magnetic head and a coil bobbin to which the coil is attached are held. And two leaf springs for holding the coil bobbin so as to be displaceable in the axial direction, and a connection circuit for externally connecting to the coil and the magnetic field, which are attached to the surfaces of the leaf springs in an electrically insulated state. A head driving device comprising: a conductor forming a part of a connection circuit to the head, wherein the conductor is formed in a shape extending along the shape of the leaf spring. 2. A method of manufacturing a head drive device, which comprises the step of producing an electric conductor having a shape conforming to the shape of a leaf spring by electroforming and attaching the electric conductor to the leaf spring.