JPH05274604A - Rotary drum for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent cross-tale and to make the drum small in size, light in weight and low in cost. CONSTITUTION:Plural pieces of magnetic heads 12 with the same azimuth are carried by a rotary drum and the rotary drum is held rotatably to a fixed drum and a rotating rotary transmission 32 is rotated integrally with the rotary drum. Then coils 34A, 34B corresponding to two magnetic heads 12A, 12B continuing each other in head switching are arranged so as not to be adjacent on the rotating rotary transmission 32 and similarly the coils 34C, 34D corresponding to two magnetic heads 12C, 12D are arranged so as not to be adjacent on the rotating rotary transmission 32. Further, tone coils 34a to 34c are arranged on a fixed rotary transmission 31 so as to correspond to these coils respectively and a short ring 35 for preventing cross-talk is provided between adjacent coils 34c, 34b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a rotary drum used in a magnetic recording / reproducing apparatus such as a video tape recorder.

[0002]

2. Description of the Related Art In recent years, the spread of video tape recorders (hereinafter abbreviated as VTRs) in ordinary households has been remarkable. Therefore, its performance has been improved year by year. However, it is a fact that it is desired to reduce the size and weight while further improving the performance as the needs of the world.

A conventional technique will be described below with reference to the drawings. FIG. 7 is a half sectional view showing the structure of a conventional VTR rotary drum device, and FIG. 8 is a half sectional view showing the structure of another conventional VTR rotary drum device.

First, the structure will be described. In FIG. 7, the rotary drum device 1 has a rotary shaft 3 fixed to a lower drum 2. A fixed-side rotary transformer 5 is fixed to the outer circumference of a shaft 4 provided at the center of the lower drum 2 by adhesion or the like. A motor stator 6 is fixed to the lower drum 2 with screws 7 on the outer side of the fixed rotary transformer 5. On the other hand, a flange 9 is rotatably held on the rotary shaft 3 via two bearings 8. The upper drum 11 is fixed to the flange 9 with a screw 10 so that the upper drum 11 can rotate together with the flange 9. Two or more audio heads 12 and video heads 13 having the same azimuth are fixed to the upper drum 11 with screws 14. Further, on the upper drum 11, the motor rotor 16 held by the fixing member 15 is arranged at a position opposed to the motor stator 6. The rotary rotary transformer 17 is provided on the flange 9 and the fixed rotary transformer 5 is provided on the flange 9.
And is fixed by adhesion or the like with a gap of several tens of μm. A coil 19 arranged in a coil groove 18 is held at a corresponding position on both rotary transformers 5 and 17.

The rotary drum device shown in FIG. 8 has substantially the same structure as the rotary drum device shown in FIG. That is,
The rotary drum device 20 is a rotary rotary transformer that is adhesively fixed to the audio head 12, the video head 13, the motor rotor 16 arranged at a position opposed to the motor stator 6, or the flange 9 screwed to the upper drum 11. It is composed of 17 etc. The difference is the configuration of the fixed-side rotary transformer 21 that is adhesively fixed to the lower drum 2. That is, the short ring 22 is formed between each of the coil grooves 18 formed in the stationary rotary transformer 21. The conventional rotary drum device has a structure as described above.

FIG. 9A is a schematic diagram showing the relationship between the head arrangement and the tape, and FIG. 9B is a schematic diagram showing the state of the head switching timing. FIG. 10A is a wiring diagram showing the connection between the head and each rotary transformer,
(B) is an enlarged view of a rotary transformer showing a state of a coil groove having no short ring, and (C) is an enlarged view of a rotary transformer showing a state of a coil groove having a short ring. Further, FIG. 11 is a schematic diagram showing a state of a magnetic flux plunging between adjacent coil grooves.

The positional relationship between the head and the tape is shown in FIG.
As shown in FIG. 3, an example having two voice heads 12 of the same azimuth is shown. The voice head 12 has an R for the right channel and an L for the left channel. The arrangement is such that the R azimuth is the voice heads 12A and 12C and the L azimuth is the voice head 1.
Like 2B and 12D, they are arranged 180 degrees opposite to each other. The tape 23 is wound around as shown in the drawing, and forms an overlapping portion 25 at the audio head 12A and the audio head 12D. The audio head 12 is arranged in a state of being inclined by θ degrees with respect to the running direction of the tape 23. As for the order of head switching, since the tape 23 is wound around the upper drum 11, which is a rotating drum, by 270 degrees, recording is performed by switching to the audio head 12 of 90 degrees ahead every 270 degrees rotation in the order of 12A->12B->12C-> 12D. Playing.

Next, the signal transmission path will be described. FIG. 10A shows the connection between the head and the rotary transformer. The audio head 12A and the coil 19A of the rotary rotary transformer 17 are electrically connected. This coil 19A is the coil 1 of the fixed-side rotary transformer 5.
9a is magnetically connected, and the coil 19a is connected to the head amplifier 24. The coils 19 are four coils 19A, 19B and 19 corresponding to the two R azimuth heads and the L azimuth heads of the voice head 12, respectively.
C, 19D and coils 19a, 19b, 19c, 19d
However, the connection relationship between the head and the coil is similar to that of the audio head 12A described above. Therefore, the signal recorded and reproduced by the audio head 12A flows into the coil 19A of the rotary rotary transformer 17. When this signal flows in, a magnetic flux ΦA is generated between the rotary side rotary transformer 17 and each coil groove 18 corresponding to the audio head 12A of the fixed side rotary transformer 5, as shown in FIG. The coil 19a is excited. As a result, the signal is transmitted to the head amplifier 24. As for the voice heads 12B, 12C, and 12D, the transmission of the signals is as shown in FIG.
As is clear from (A) and FIG. 11, it is exactly the same.

In the above relationship, the crosstalk phenomenon will be examined. The crosstalk phenomenon is likely to occur when the head signal is switched. For example, when switching from the audio head 12A to the audio head 12B, the audio head 12A records or reproduces a signal at the end of the winding of the tape 23 and the audio head 12B at the beginning of the winding of the tape 23. These are performed in the overlapping portion 25 around which the tape 23 is wound. As shown in FIG. 11, when the audio head 12A and the audio head 12B operate at the time of switching, the coils 19A and 19B of the rotary rotary transformer 17 and the coils 19a and 19b of the fixed rotary transformer 5 are adjacent to each other, so that the rotary transformer 1
Between 7 and 5, the signal from the audio head 12A is transmitted to the audio head 12
B, and the signal from the voice head 12B is the voice head 12B.
Each of which jumps into the
BA is generated. That is, a phenomenon called adjacent signal interference or crosstalk occurs, which causes deterioration of sound quality.

Therefore, in order to prevent this crosstalk phenomenon, the distance between the adjacent coil grooves 18 formed in the rotary transformers 17 and 5 is increased as shown in FIG. 7, or the fixed side is formed as shown in FIG. A countermeasure has been taken by providing a short ring 22 between the coil grooves 18 of the rotary transformer 21. This relationship is shown in FIG.
That is, every time a head switching signal is generated, a head output without crosstalk is obtained in the structure with the short ring 22 as shown in FIG. 8, but with a structure without the short ring 22 as in FIG. Since only the head output with talk can be obtained, the distance between the grooves must be large.

[0011]

As described above, in the arrangement structure of the coil grooves of the rotary transformer of the conventional rotary drum device, in order to prevent crosstalk during head switching, the gap between the adjacent coil grooves of the rotary transformer is prevented. Although measures have been taken to increase the distance and to form a short ring between the coil grooves, the size of the rotary transformer becomes large, which is a major obstacle to downsizing and weight reduction. Moreover, such a measure leads to an increase in the cost of the rotary transformer. Furthermore,
Although it is possible to reduce the crosstalk phenomenon only by increasing the distance between adjacent coil grooves as shown in FIG. 7, it is difficult to completely prevent the crosstalk phenomenon.

The present invention has been made in order to solve the above-mentioned conventional problems, and prevents crosstalk in the rotary transformer to improve sound quality performance, and also makes the rotary drum smaller and lighter. The aim is to achieve higher efficiency and lower costs.

[0013]

A rotary drum of a magnetic recording / reproducing apparatus according to claim 1 comprises a fixed drum and a rotary drum carrying a plurality of magnetic heads of the same azimuth and rotatably held with respect to the fixed drum. , A rotary rotary transformer having coil grooves respectively accommodating coils for generating magnetic flux corresponding to each of the magnetic heads and rotating integrally with the rotary drum, and is provided integrally with the fixed drum so as to face the rotary rotary transformer. A fixed rotary transformer having a coil groove accommodating a coil for generating a magnetic flux corresponding to each coil of the rotary rotary transformer, wherein a magnetic recording / reproducing apparatus for sequentially switching magnetic heads to perform magnetic recording / reproduction is used. When arranging the coil groove in the coil, the carp corresponding to two consecutive heads in the head switching order. Those arranged without adjacent grooves to each other.

A rotary drum of a magnetic recording / reproducing apparatus according to a second aspect of the present invention includes a fixed drum, a rotary drum that holds a plurality of magnetic heads having the same azimuth, and is rotatably held with respect to the fixed drum. A rotary rotary transformer having coil grooves for accommodating coils that generate corresponding magnetic fluxes and rotating integrally with the rotary drum, and a rotary drum provided integrally with the fixed drum so as to face the rotary rotary transformer. A fixed rotary transformer having a coil groove for accommodating a coil that generates a magnetic flux corresponding to the coil, and a magnetic recording / reproducing apparatus for sequentially switching magnetic heads to perform magnetic recording / reproducing, and disposing the coil groove on the rotary rotary transformer. At the time of head switching, the number of coil groove pairs corresponding to two consecutive heads is smaller. Those arranged so as not to be adjacent to the coil groove to each other in Kutomo pair.

According to a third aspect of the present invention, there is provided a rotating drum of the magnetic recording / reproducing apparatus according to the second aspect, wherein between the coil grooves on the rotary rotary transformer or the fixed rotary transformer, which are adjacent to each other. Is provided with a predetermined crosstalk preventing means.

[0016]

According to the above construction, the coil groove on the rotary transformer corresponding to the operating magnetic head and the rotary transformer corresponding to the magnetic head before or after the operating magnetic head. By disposing the coil groove so as not to be adjacent to each other, adjacent magnetic fluxes do not interfere with each other during operation, and crosstalk in the rotary transformer can be effectively prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a half sectional view showing the structure of a rotary drum device for a VTR according to the present invention. The configuration of FIG. 1 is similar to that of FIG.
Since it has substantially the same structure as the conventional rotary drum device shown in FIG. 1, the same reference numerals are used for the same members to simplify the description.

The rotary drum device of FIG. 1 shows an example in which two identical azimuth heads are mounted. In the figure, the rotary drum device 30 has the following structure. A rotary shaft 3 and a motor stator 6 are held on the lower drum 2, and a fixed rotary transformer 31 is fixed thereto by adhesion or the like.
On the other hand, the upper drum 11 has an audio head 12 and a video head 13 having two or more identical azimuths, a motor rotor 16 arranged at a position opposed to the motor stator 6,
Alternatively, it has a fixed rotary transformer 31 and a rotary rotary transformer 32 which is rotatably held with a gap of several tens of μm and fixed to the flange 9 by adhesion or the like. The above structure is substantially the same as that of the rotary drum device shown in FIG. 7, except that both rotary transformers 31 are different.
And the arrangement of the coil groove 33 and the coil 34 formed in 32. The details will be described later with reference to FIG.
In the arrangement of 4, the four coils are arranged so that the coil 34 corresponding to the voice head 12 in operation is not adjacent to the coil 34 corresponding to the voice head 12 before and the voice head 12 after one. 34A, 34C, 34B and 34D are arranged in this order. As a result, the coil groove 33 on the rotary transformer can be arranged closer to the conventional one.

Since the embodiment of FIG. 1 is an example in which two identical azimuth heads are mounted, the coils 34B and 34C corresponding to two magnetic heads that are continuously switched are in close proximity to each other, so that the coil 34B. And the coil 34C are close to each other. Therefore, the short ring 35, which is a coil for preventing crosstalk, is provided, and the other coil groove 3 is provided.
3 are arranged as close to each other as possible.
Instead of the short ring 35, a coil for a rotation erasing head or the like may be used.

FIG. 2A is a schematic diagram showing the relationship between the head arrangement and the tape, and FIG. 2B is a schematic diagram showing the state of the head switching timing. FIG. 3A is a wiring diagram showing the connection between the head and each rotary transformer, and FIG. 3B is an enlarged view of the rotary transformer showing the state of the coil groove. Further, FIG. 6 is a schematic diagram showing a state of a magnetic flux plunging between adjacent coil grooves. 2 (A) and FIG. 3 (A) are the same as FIG. 9 (A) and FIG.

As shown in FIG. 3B, the arrangement of the coils with respect to the arrangement of the heads is such that the coil 34C (c) is adjacent to the coil 34A (a) and the coil 34B is adjacent to the coil 34C (c). (B), and coil 34B (b)
The coil grooves 33 of the rotary transformers 31 and 32 are arranged next to each other so that the coils 34D (d) are arranged. As a result, the coil 34A (a) and the coil 3 are
The distances between the coil grooves of 4C (c) and between the coil grooves of the coils 34B (b) and 34D (d) are as close as possible. However, since the same azimuth head is two, as described above, the coils 34B and 34C operate simultaneously at the time of switching, so that the coils 34b and 34c are operated.
A short ring 35 is provided between the coil grooves.

Looking at the relationship with crosstalk with reference to FIG. 2, it is possible to obtain a head output without crosstalk with respect to the head switching signal at the head switching timing. This relationship will be described with reference to FIG. 6. Since the voice head 12C is not operating when the head switching magnetic flux ΦA is generated, the jump magnetic flux ΦCA is not generated and the coil groove distance can be reduced. It will be possible.

Next, another embodiment of the present invention will be described. FIG. 4A is a schematic diagram showing the relationship between the head arrangement and the tape, and FIG. 4B is a schematic diagram showing the state of the head switching timing. FIG. 5A is a wiring diagram showing the connection between the head and each rotary transformer, and FIG. 5B is an enlarged view of the rotary transformer showing the state of the coil grooves.

The second embodiment shows an example in which three identical azimuth heads are mounted. From FIG. 4 (A), the audio head 40 is an audio head 40A, C, E as R azimuth.
However, as the L azimuth, the voice heads 40B, 40D, 40F are arranged every other one. The tape 41 has a tape overlap portion 42 formed at the R azimuth 40A and the L azimuth 40F. The connection is shown in Fig. 5 (A)
As described above, the coils 44A of the rotary rotary transformer 43 are
B, C, D, E, and F correspond, and further, coils 44a, b, c, d, e, and f of the fixed side rotary transformer 45 correspond, and all of them are connected to the head amplifier 24.

The arrangement of the coils in the rotary transformer is, as shown in FIG. 5B, a coil 44C (c) next to the coil 44A (a) and a coil 44E (e) next to the coil 44C (c). ), A coil 44B (b) next to the coil 44E (e), a coil 44D (d) next to the coil 44B (b), and a coil 44F (next to the coil 44D (d). The coil grooves 46 are arranged so as to be arranged respectively in (f). Of course, the coil 44A of the rotary rotary transformer 43 and the coil 44a of the fixed rotary transformer 45 correspond to each other. In the case of the second embodiment, since the adjacent heads do not operate simultaneously, the coil for preventing crosstalk is completely unnecessary. As a result, even if the distance between the coil grooves is made as short as possible, as shown in FIG.
Since the voice head 12C is not operating when the noise occurs, the inrush magnetic flux ΦCA does not occur. Therefore, at the timing of head switching, a head output without crosstalk can be obtained with respect to the head switching signal, and the distance between the coil grooves can be greatly reduced.

[0027]

As described above, according to the rotary drum of the magnetic recording / reproducing apparatus of the present invention, when the coils are arranged on the rotary transformer, the grooves corresponding to the two heads which are continuously switched and operated are formed. Since they are not adjacent to each other, it is possible to prevent the generation of jump magnetic flux and prevent crosstalk during head switching. For this reason,
It is possible to greatly reduce the distance between the grooves of the coil. Further, this makes it possible to reduce the size and weight of the rotary drum device, and thus to achieve cost reduction.

[Brief description of drawings]

FIG. 1 is a half sectional view showing the structure of a rotary drum device for a VTR according to the present invention.

2A and 2B show an embodiment of the present invention, FIG. 2A is a schematic diagram showing a relationship between a head arrangement and a tape, and FIG. 2B is a schematic diagram showing a state of head switching timing.

FIG. 3 shows an embodiment of the present invention, (A) is a wiring diagram showing the connection between the head and each rotary transformer, and (B) is an enlarged view of the rotary transformer showing the state of the coil groove.

4A and 4B show another embodiment of the present invention, in which FIG. 4A is a schematic view showing the relationship between the head arrangement and the tape, and FIG.
FIG. 4 is a schematic diagram showing a state of head switching timing.

FIG. 5A is a wiring diagram showing a connection between a head and each rotary transformer according to another embodiment of the present invention,
(B) is an enlarged view of the rotary transformer showing the state of the coil groove.

FIG. 6 is a schematic diagram showing a state of a magnetic flux plunging between adjacent coil grooves according to an embodiment of the present invention.

FIG. 7 is a half sectional view showing the structure of a conventional VTR rotary drum device.

FIG. 8 is a half cross-sectional view showing the structure of a VTR rotary drum device according to another conventional example.

FIG. 9A is a schematic diagram showing the relationship between the head arrangement and the tape, and FIG. 9B is a schematic diagram showing the state of head switching timing.

FIG. 10A is a wiring diagram showing a connection between the head and each rotary transformer, and FIG. 10B is an enlarged view of the rotary transformer showing a state of a coil groove without a short ring;
(C) is an enlarged view of a rotary transformer showing a state of a coil groove with a short ring.

FIG. 11 is a schematic diagram showing a state of a magnetic flux plunging between adjacent coil grooves.

[Explanation of symbols]

 1, 20, 30 rotating drum device 3 rotating shaft 5, 21, 31 fixed side rotary transformer 11 upper drum 12, 40 audio head 17, 32 rotating side rotary transformer 18, 33 coil groove 19, 34 coil 22 short ring 23 tape

Claims (3)

[Claims] 1. A fixed drum, a rotary drum carrying a plurality of magnetic heads of the same azimuth and rotatably held with respect to the fixed drum, and a coil for generating a magnetic flux corresponding to each of the magnetic heads. A rotary rotary transformer that has a coil groove and rotates integrally with the rotary drum,
A fixed rotary transformer which is provided integrally with the fixed drum so as to face the rotary rotary transformer and has a coil groove for accommodating a coil for generating a magnetic flux corresponding to each coil of the rotary rotary transformer. In a magnetic recording / reproducing apparatus for switching and performing magnetic recording / reproducing, when arranging coil grooves on the rotary rotary transformer, coil grooves corresponding to two consecutive heads are arranged so as not to be adjacent to each other in the head switching order. A rotating drum of a magnetic recording / reproducing apparatus characterized by the above. 2. A fixed drum, a rotary drum that holds a plurality of magnetic heads of the same azimuth and is rotatably held with respect to the fixed drum, and a coil that generates magnetic flux corresponding to each of the magnetic heads. A rotary rotary transformer that has a coil groove and rotates integrally with the rotary drum,
A fixed rotary transformer which is provided integrally with the fixed drum so as to face the rotary rotary transformer and has a coil groove for accommodating a coil for generating a magnetic flux corresponding to each coil of the rotary rotary transformer. In a magnetic recording / reproducing apparatus for performing magnetic recording / reproducing by switching, in disposing the coil groove on the rotary rotary transformer, in at least one set of coil grooves corresponding to two consecutive heads in a head switching order. Is a rotary drum of a magnetic recording / reproducing apparatus, in which coil grooves are arranged not adjacent to each other. 3. The rotary drum according to claim 2, wherein a predetermined crosstalk preventing member is provided between the coil grooves adjacent to each other among the coil grooves on the rotary rotary transformer or the fixed rotary transformer. A rotating drum of a magnetic recording / reproducing apparatus, characterized by: