JPH0512602A - Rotary head drum - Google Patents

Abstract

PURPOSE:To easily and surely secure an earth by entirely unnecessitating a special relaying substrate for connecting the earth line and a working process thereof. CONSTITUTION:A contact terminal connected to the earth line is formed at the side confronted with a fixed drum 2 on a substrate 20 which is mounted on a rotary transformer 7 at the fixing side of a rotary transformer 6. When the rotary transformer 7 at the fixing side of rotary transformer 6 is mounted on the fixed drum 2, an elastic conductive member 21 pressed in contact respectively with the contact terminal and the fixed drum 2 is arranged to make so that the earth line of substrate 20 and the fixed drum 2 are electrically connected through this conductive member 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to various AV (audio / visual) devices that perform magnetic recording / reproduction by a helical scan system such as a VTR (video tape recorder) and a DAT (digital audio tape recorder). Rotary head drum.

[0002]

2. Description of the Related Art A rotary head drum applied to a conventional VTR has a structure as shown in FIG. In this figure, 1 is a drum base, and this drum base 1
The fixed drum 2 is attached on top. 3 is a rotary drum, and in a state where the axis line is aligned with the fixed drum 2,
It is rotatably supported and is rotationally driven by a drum motor (not shown). Magnetic heads 4 and 5 for magnetic recording / reproduction are attached to the rotary drum 3, and signals are transferred between the magnetic heads 4 and 5 and two other magnetic heads (not shown) by a rotary transformer. 6 through. The rotary transformer 6 is composed of a fixed rotary transformer 7 mounted on the fixed drum 2 side and a rotary rotary transformer 8 mounted on the rotary drum 3 side. The fixed-side rotary transformer 7 and the rotary-side rotary transformer 8 face each other with a gap therebetween and are electromagnetically coupled. That is, the fixed-side rotary transformer 7 has a disk-shaped fixed iron core 7a.
Has four concentric circular grooves formed on the end face thereof, and four sets of fixed coils 7b to 7e are arranged in the respective grooves. Similarly, the rotary rotary transformer 8 has a disc shape. -Shaped rotary core 8a has four concentric circular grooves formed on the end surface thereof, and four sets of rotary coils 8b to 8e are arranged in the respective grooves.

A fixed end rotary transformer 7 of the rotary transformer 6 is mounted with a base end portion of a flexible printed circuit board 9 as shown in FIGS. 5 and 6 in order to exchange signals with a recording / reproducing amplifier. Has been. Printed circuit board 9
Eight signal lines la to lh connected to both ends of the four sets of fixed coils 7b to 7e are formed on the upper side, and these signal lines la to lh are connected to a recording / reproducing amplifier. It The printed circuit board 9 requires a separate ground line in addition to the signal line. In order to ground the ground line provided on the board 9, the following relay board 10 is conventionally used.

The relay board 10 is attached to the tip portion of the printed board 9, and the tip portion of the printed board 9 is connected to a card edge connector 11 provided on the relay board 10. Then, on the printed circuit board 9,
8 connected to both ends of four sets of fixed coils 7b to 7e
Book signal lines la to lh are formed, and these signal lines la to lh are connected to the signal pins 12 a to 12 h of the pin connector 12 provided on the relay board 10 via the card edge connector 11, respectively. , Each of these signal pins 1
It is connected to the recording / reproducing amplifier via 2a to 12h. The grounding of the rotary drum is performed through the grounding pin 12i of the pin connector 12 through the grounding line 1 on the relay board 10.
The end of 3 is screwed or soldered to the drum base 1 with a screw 14.

[0005]

As described above, the conventional rotary head drum described above requires the relay substrate 10 for grounding, and an external recording / reproducing amplifier and a signal are provided via the relay substrate 10. Is being exchanged.
To secure the ground in this way, the relay board 1
Parts such as 0 and screws 14 are indispensable, resulting in an increase in the number of parts and an increase in the assembly process. There is also a problem that space saving cannot be achieved. Further, when the drum base 1 is made of an insulating material (for example, synthetic resin) for the purpose of weight reduction, there is a problem that it becomes impossible to secure the ground.

The present invention has been made in view of the above-mentioned circumstances, and does not require any special relay board or working process for connecting the earth line, and can easily and surely secure the earthing head. Intended to provide drums.

[0007]

According to the present invention, in order to solve the above-mentioned problems, a ground line is connected to a portion of a substrate, one end of which is attached to a fixed-side rotary transformer, facing a portion of a fixed drum. Contact terminals,
In a state where the fixed side rotary transformer of the rotary transformer is mounted on the fixed drum, elastic conductive members that are in pressure contact with the contact terminals and a part of the fixed drum are mounted on the fixed drum.

[0008]

According to the above construction, in the work process of mounting the fixed side rotary transformer of the rotary transformer on the fixed drum,
Since the contact terminal connected to the ground line of the substrate attached to the fixed-side rotary transformer of the rotary transformer and a part of the fixed drum are electrically connected through the conductive member, the conventional There is no need for a special relay board or work process for connecting such an earth line.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. In the description of FIG. 1, the same components as those of the rotary drum head shown in FIG. 4 as a conventional example are designated by the same reference numerals, and a duplicate description thereof will be partially omitted. As shown in Figure 1,
The base end portion 20a of the flexible printed board 20 for exchanging signals between the rotary transformer 6 and a recording / reproducing amplifier is attached to the fixed rotary transformer 7 of the rotary transformer 6 with an adhesive or the like. In the present embodiment, a concave portion 2a is provided in a part of the surface of the fixed drum 2 facing the fixed-side rotary transformer 7, and in the concave portion 2a,
A conductive member 21 is installed. Then, when the fixed-side rotary transformer 7 is attached to the fixed drum 2, the conductive member 21 is pressed into contact with the base end portion 20a of the substrate 20 and crushed in the recess 2a.

As shown in FIG. 2, eight signal lines La to Lh extending from the base end portion 20a to the tip end portion 20b are formed on the printed circuit board 20, and these signal lines L are formed.
One end of each of a to Lh is connected to both ends of four sets of fixed coils 7b to 7e by soldering. Further, on the base end portion 20a of the printed circuit board 20, a land Li having an area sufficient for ensuring electrical contact with the conductive member 21 is formed by solder plating or the like. The land Li is connected to the earth line Lj of the rotary transformer, and the earth line Lj extends to the tip portion 20b of the printed circuit board 20. These signal lines La to Lh
And the ground line Lj are connected to the tip portion 20 of the printed circuit board 20.
In b, it is directly connected to the recording / playback amplifier. For example, as shown in FIG. 3, the conductive member 21 is formed by forming a conductive metal film 21b on the outer peripheral surface of an elastic member 21a having a U-shaped cross section. The elastic member 21a is made of, for example, a foamed resin such as polyurethane foam or sponge rubber having appropriate elasticity. Further, the conductive metal film 21b is made of a metal material having a resistance value of several Ω or less.

In the above structure, when the fixed side rotary transformer 7 of the rotary transformer 6 is mounted on the fixed drum 2, the conductive member 21 is arranged in the recess 2a of the fixed drum 2 so that A part of it elastically deforms due to the pressing force at the time of mounting, and its one end surface and the other end surface are in pressure contact with the land Li on the printed circuit board 20 and the concave portion 2a of the fixed drum 2, respectively. As a result, the ground line Lj connected to the land Li and the fixed drum 2 are electrically connected.

According to this embodiment, the ground line L on the printed circuit board 20 is used in the work process of mounting the fixed-side rotary transformer 7 of the rotary transformer 6 on the fixed drum 2.
Between the land Li connected to j and the fixed drum 2,
Since it is electrically conducted through the conductive member 21,
The special relay board 10 for connecting the earth line as shown in FIG. 2 and the working process are not required at all, and the earth line can be directly connected to the fixed drum 2. When the S / N ratio was measured under the same conditions in the above-described embodiment, when the conductive member 21 was provided to secure the ground,
Compared to the case where the conductive member 21 is not provided, S / N
It has been found that the ratio is improved by 1-5 dB.

Although the conductive member 21 having a U-shaped cross section is used in the above-described embodiment, the elastic force is changed by the pressing force when the fixed side rotary transformer 7 of the rotary transformer 6 is mounted on the fixed drum 2. Any material and shape may be used as long as the material is deformed and electrical continuity is secured. For example, a rectangular parallelepiped shape, a tape shape, and a spherical elastic member can be considered. Further, in the above-mentioned example, the elastic portion and the conductive portion are formed by separate members, but the conductive elastic member may be formed integrally. Further, in the above-mentioned example, the rotary transformer 6 which exchanges signals for four channels has been described as an example, but two channels may of course be used.

[0014]

As described above, according to the present invention,
In the work process of mounting the fixed-side rotary transformer of the rotary transformer on the fixed drum, a conductive member is provided between the contact terminal of the ground line of the substrate attached to the fixed-side rotary transformer of the rotary transformer and a part of the fixed drum. Since it is electrically conducted via, no special relay board or work process for connecting the ground line like the conventional one is required, and the number of parts can be reduced and the manufacturing process can be simplified. This saves space. Also, since the ground line can be directly connected to the fixed drum,
Even if the drum base is made of an insulating material, the ground can be secured. Further, since the relay substrate and the like are not present at all in the middle of the earth line, the S / N ratio can be improved.
Furthermore, since the ground can be taken at a position very close to the rotary transformer, the function as the ground is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a rotary drum head according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a printed circuit board applied to an embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration of a conductive member applied to one embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a conventional rotary drum head.

FIG. 5 is a plan view showing a configuration of a fixed portion of a conventional rotary drum head.

FIG. 6 is a plan view showing a configuration of a printed circuit board used in a conventional rotary drum head.

[Explanation of symbols]

 2 ... Fixed drum 3 ... Rotation drum 6 ... Rotation transformer 7 ... Fixed side rotation transformer 8 ... Rotation side rotation transformer 20 ... Flexible printed circuit board La-Lh ... Signal line Li ... Land (contact terminal) Lj ... Ground line 21 ... Conductivity Member 21a ... Elastic member 21b ... Conductive metal film

Claims (1)

Claim: What is claimed is: 1. A rotary transformer comprises a fixed rotary transformer and a rotary rotary transformer, which face each other with a gap therebetween.
In a rotary head drum mounted on a fixed drum and a rotary drum, one end is attached to the fixed side rotary transformer, and a signal line for transmitting and receiving a signal between the rotary transformer and an external circuit is formed. In addition, the ground line of the rotary drum is formed, and the substrate on which the contact terminal connected to the ground line is formed in a portion facing the part of the fixed drum, and the fixed side rotation of the rotary transformer. A rotary head drum, comprising: an elastic conductive member that is in pressure contact with each of the contact terminals and a part of the fixed drum when the transformer is mounted on the fixed drum.