JPH07105502A - Rotating magnetic head device - Google Patents

Abstract

PURPOSE:To decrease the crosstalks between adjacent channels by reversing the directions of the currents flowing in the adjacent channels of the plural channels. CONSTITUTION:A first video channel line 40 and a second video channel line 42 are respectively arranged in a stator core 12 and a rotor core 16 and the weak currents flowing respectively in both lines 40, 42 are reversed. The current flowing in the first channel line 40 flows upward of the plane of Fig. and the current of the second channel line 42 flows downward of the plane of Fig. The directions of the weak currents respectively flowing in both adjacent lines 40 and 42 are reversed in such a manner, by which the fogging of magnetic fields, i.e., crosstalks, generated by the weak currents flowing in the respective channel lines 40, 42 in the stator core 12 and the rotor core 16 of the rotary trans at the time of recording/reproducing are decreased.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a VTR, DAT, or DD
The present invention relates to improvement of a rotary magnetic head device such as S (digital data storage).

[0002]

2. Description of the Related Art In a VTR, for example, a rotary magnetic head device is used for reproducing information stored on a magnetic tape or for recording / reproducing information. The rotary magnetic head device includes a rotor section and a stator section. Signals are exchanged between the rotor portion and the stator portion through a rotary transformer in a non-contact manner.

This rotary transformer is composed of a rotor core provided in the rotor portion and a stator core provided in the stator portion. As illustrated in FIG. 7, on the rotor core 1 and the stator core 3, channel lines 2 and 4 for video channels are arranged in a ring shape. Moreover, a short ring S is arranged between the channel lines 2 and 4.

In the core (rotor core or stator core) shown in FIG. 7, the channel lines 2 and 4 are circled in circles.
As shown by the mark, a weak current flows in the opposite side of the paper surface of FIG. That is, currents flowing in the same direction flow in the channel lines 2 and 4, and the polarities are the same.

[0005]

By providing a short ring S between these adjacent channel lines 2 and 4, fogging from a magnetic field generated by a weak current flowing in each channel line 2 and 4, that is, crosstalk. (Inter-channel transformer coupling crosstalk, especially at high frequencies) is reduced.

For example, in a flat plate type rotary transformer,
The short ring S for countermeasures against crosstalk is, for example, a metal ring wire having a wire diameter of about 0.1 mm to 0.2 mm. Alternatively, in a vertical rotary transformer for business use, the short ring S for countering crosstalk is a metal ring made of brass or the like. However, with the demand for lower prices of VTR devices, especially in the low-price competition in the consumer video area, it is required to reduce the cost of manufacturing parts as well as the performance, and it is necessary to give priority to cost.

Therefore, if the short ring S is arranged between the channel lines 2 and 4 as in the conventional case, there is a problem that the manufacturing cost increases.

Therefore, the present invention has been made in order to solve the above problems, and it is possible to reduce the crosstalk between adjacent channels without using a short ring and to reduce the cost. The purpose is to provide a device.

[0009]

According to the present invention, there is provided a rotary magnetic head device including a rotary transformer having a plurality of channels arranged therein, in which the directions of currents flowing in the adjacent channels are reversed. This is achieved by a rotary magnetic head device configured to.

In the present invention, each of the channels is preferably a video channel, and preferably the rotary transformer further includes a short ring.

[0011]

The crosstalk between adjacent channels is reduced by reversing the directions of the currents flowing in the adjacent channels, that is, by reversing the polarities of the adjacent channels.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 shows a preferred embodiment of the rotary magnetic head device of the present invention. The rotary magnetic head device drum 10 is for recording / reproducing information on / from a recording medium such as a VTR tape or reproducing information from the recording medium.

In FIG. 1, a rotary magnetic head device 10 is provided.
Is a cylindrical upper drum 13 to which the magnetic head 14 is fixed.
And a cylindrical lower drum 11 having substantially the same diameter as the upper drum 13. The upper drum 13 is fixed to the rotary shaft 17 via a flange 15. The rotary shaft 17 is fixed to the rotor 19 of the motor, and the rotor 19 of the motor rotates to rotate the upper drum 13.

The magnetic head 14 helically scans a magnetic tape (not shown) which is wound around the outer periphery of the rotary drum 13 at a predetermined angle and runs obliquely so as to record or reproduce an information signal on or from the magnetic tape. It has become.

The lower drum 11 is a fixed drum which is supported by a rotary bearing 22 with respect to the rotary shaft 17, and which does not rotate when the rotary shaft 17 rotates. As shown in the drawing, a flat or disk-shaped stator core 12 for a rotary transformer is mounted on the lower drum 11. The stator core 12 is the upper drum 1
It faces the rotor core 16 mounted on the lower surface of No. 3 with a predetermined gap.

Here, the rotor core 16 of the upper drum 13
Are connected to the magnetic head 14 via a head amplifier (not shown). On the other hand, the stator core 1 of the lower drum 11
2 is connected to the signal processing circuit on the device body side.

As a result, the rotor core 16 and the stator core 12 constitute a flat rotary transformer, and the recording signal and the reproducing signal are exchanged between the magnetic head 14 and the main body of the apparatus in a non-contact manner. Has become.

Rotor core 1 of the rotary transformer described above
6 and the stator core 12 are configured as shown in FIG. That is, the first video channel line 40 and the second video channel line 42 are arranged in the stator core 12 and the rotor core 16, respectively.

As shown in FIG. 2, the adjacent first and second channel lines 40 and 42 have opposite weak currents. That is, the polarities of the first channel line 40 and the second channel line 42 are opposite.

The current flowing through the first channel line 40 is
The current flows upward with respect to the paper surface of FIG. Further, the current of the second channel line 42 flows downward with respect to the paper surface.

As described above, by reversing the directions of the weak currents flowing through the first channel line 40 and the second channel line 42, which are adjacent to each other, the stator core 12 and the rotor core 16 of the rotary transformer can be respectively recorded / reproduced. Fogging of the magnetic field generated by the weak currents flowing in the channel lines 40 and 42, that is, crosstalk can be reduced. In the first channel line 40 and the second channel line 42, as indicated by arrows Y1 and Y2 in FIG. 3, the currents flow in opposite directions, so that the magnetic fields of the two channel lines are in the directions of canceling each other. It will occur and it will be hard to cover.

Next, please refer to FIG. 4 and FIG. FIG. 4 shows 8
1 shows a configuration example of a rotary magnetic head device (8 mm drum) for a millimeter VTR.

In FIG. 4, the arrangement of the plurality of channel lines is 1, 2, 3 from the inside. Corresponding to these channel arrangements 1, 2 and 3, channel lines as shown in FIG. 4 are arranged on the rotor core side and the stator core side, respectively.

In FIG. 4, the channel arrangement 1 is FE.
It is CH (Flying Erase Channel). Channel arrangement 2 is BCH (video channel 2CH). Further, the channel arrangement 3 is ACH (video channel 1CH).

The current directions in the adjacent channel arrangements 2 and 3 in FIG. 4 are opposite and the polarities are opposite. A short ring is positively arranged between the channel arrangements 1 and 2. Thus, channel arrangements 1 and 2
A short ring is actively provided between the tracks to prevent beats during recording. That is, a large current flows through the flying erase channel FECH during recording, but by using this short ring, this large current affects a weak current flowing through the video channels BCH and ACH (appears as a beat). Prevent it. On the other hand, since the directions of the currents are opposite between the channel arrangements 2 and 3, it is not necessary to provide the short ring which has been necessary in the past.

Next, another embodiment shown in FIG. 5 will be described. Figure 5
1 shows an example of a VHS rotary magnetic head device (VHS drum). Channel arrangement is from 1 to 7. The current directions in adjacent channel arrangements 1 and 2 are opposite and the polarities are opposite. Also between adjacent channel arrangements 2 and 3 and channel arrangements 3 and 4
Even between, the directions of the respective currents flowing are opposite, and the polarities are opposite. Since the directions of the electric currents are opposite between the adjacent channel arrangements 2 and 3 in FIG. 5, it is not necessary to provide a short ring, which is conventionally required. It is also necessary to provide a short ring between the channel arrangements 4 and 5. This is to prevent beats during recording.

In FIG. 5, SP1CH and SP2CH on the rotor core side indicate standard mode channels, and EP1C
H and EP2CH indicate triple mode channels. Further, HF1CH and HF2CH indicate high-fidelity audio channels, and FECH indicates flying erase channels.

In the embodiment of the present invention, basically the short ring between the video channels can be eliminated.

Next, referring to FIG. FIG. 6 shows crosstalk frequency characteristics of channel arrangements 2 and 3.
The characteristic curve L1 simply shows the frequency characteristic without the short ring. On the other hand, the characteristic curve L2 is
Channel arrangement 2 with no short ring and adjacent
The case where the polarities are changed by reversing the directions of the currents flowing in 3 and 3 is shown. As described above, the characteristic curve L2 in the embodiment of the present invention can obviously reduce the value of crosstalk (dB) as compared with the characteristic curve L1 in the case where the short ring is not provided. According to an embodiment of the present invention,
The degree of improvement of crosstalk varies depending on the design of the rotary transformer, but can be improved by about 20 dB or more.

The present invention is not limited to the above embodiment. Although the above-described embodiment describes the rotary magnetic head device for VTR, the present invention is not limited to this. For example, the present invention can be applied to a rotary magnetic head device such as DAT or DDS (digital data storage). Further, in the illustrated embodiment, an example of a flat rotary transformer is shown, but the present invention is not limited to this, and the present invention can be applied to a tubular rotary transformer.

[0032]

As described above, according to the first and second aspects of the present invention, crosstalk between adjacent channels can be reduced without using a short ring, and the manufacturing cost can be reduced. According to the third aspect of the invention, the crosstalk can be further reduced by using the short ring together.

[Brief description of drawings]

FIG. 1 is a sectional view showing a preferred embodiment of a rotary magnetic head device of the present invention.

FIG. 2 is a view showing a cross section of a rotor core or a stator core of the rotary transformer in FIG.

FIG. 3 is a diagram showing that the current directions of the channel lines in FIG. 2 are reversed.

FIG. 4 is a diagram showing a specific example of a rotary magnetic head device for an 8 mm VTR, which is a preferred embodiment of the present invention.

FIG. 5 is a diagram showing a specific example of a rotary magnetic head device for VHS according to another preferred embodiment of the present invention.

FIG. 6 is a diagram showing frequency characteristics of crosstalk in a rotary transformer when there is no short ring and frequency characteristics when there is no short ring and the polarity is changed by changing the direction of current.

FIG. 7 is a sectional view showing a part of a core of a conventional rotary transformer.

[Explanation of symbols]

 10 Rotary Magnetic Head Device 12 Stator Core 16 Rotor Core 40 First Channel Line 42 Second Channel Line S Short Ring

Claims (3)

[Claims] 1. A rotary magnetic head device including a rotary transformer having a plurality of channels arranged, wherein the directions of currents flowing through the adjacent channels are reversed. apparatus. 2. The rotary magnetic head device according to claim 1, wherein each of the channels is a video channel. 3. The rotary magnetic head device according to claim 1, wherein a short ring is further used in combination with the rotary transformer.