JPH1049842A - Rotary magnetic head apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize reduction of the cost, by extending the end point of a coil lead wire led from a coil arranged within a rotary trans-rotor core up to a magnetic head for direct connection to a magnetic head terminal block. SOLUTION: The magnetic heads 1a, 1b are connected and fixed to the end part of a head space 2 and are then tightened to a rotary drum 3a with a fitting screw 4. The rotary trans-rotor 13a is provided with a lead wire 13e and this lead wire is connected by the soldering to the terminal of printed wiring substrate 8 of the head space 2 to assure electrical continuity between the magnetic heads 1a, 1b and rotary trans-rotor 13a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a portable magnetic recording / reproducing apparatus, a portable VTR is known. Conventional portable VT
An example of a rotating magnetic head device of R is disclosed in
No. 10 publication. According to this publication, the structure is complicated, the number of parts is large, and special parts are used.
The production cost is high for consumer equipment. That is, a special type of bearing in which a groove is machined in the shaft is used as the bearing. Further, a coil lead wire drawn from a coil provided in the rotary transformer rotor core is electrically connected to a magnetic head via a head contact terminal and a head base. In general, gold contacts are used for the head contact terminals, and are expensive parts. Further, the rotary drum is fitted with high precision to the flange in which the bearing is fitted with high precision, and is fixed by screws. Therefore, the dimensional accuracy of the flange requires a high degree of mechanical accuracy, and it is an expensive component.

Another conventional example having a slightly simplified structure and a small number of parts is disclosed in Japanese Patent Application Laid-Open No. 6-162410. The bearing is of a standard type and is mounted on the upper drum (rotary drum), so there is no flange. However, the rotor of the rotary transformer is not mounted on the upper drum (rotary drum), and although not described in the publication, a member for mounting the rotor of the rotary transformer is shown in FIG. It is also evident from FIG. 1 that a head contact terminal is required for connection between the rotor of the rotary transformer and the magnetic head.

As another conventional example, Japanese Patent Application Laid-Open No. 7-32
No. 0244 is known. There is no flange, the structure is further simplified and the number of parts is small, but since the inner diameter of the rotary transformer can not be reduced, the outer diameter of the rotary transformer increases, and the size of the rotary transformer Since the magnetic head is spread over the position covering the line head screw, the magnetic head cannot be removed after the rotor of the rotary transformer is attached by bonding or the like.

In recording (photographing) with a portable VTR, the recording time is short and recording stops are repeated many times.
Since the continuity of the signal is likely to be deteriorated, as a countermeasure, it is necessary to erase an unnecessary recorded signal at the start of recording and start recording at the next instant. Therefore, a rotating magnetic head device used in a portable magnetic recording / reproducing device requires a magnetic head for erasing (flying erase head) in the same rotating drum. Also in this case, the above-mentioned conventional example is not described.

[0006] On the other hand, stationary VTRs having only a magnetic head for video have been produced as a popular type. When producing a portable VTR with a flying erase function and a popular type at the same time, it is necessary to share parts and to make parts manufacturing methods common. In the above-mentioned known documents, no consideration has been given to sharing of these components or sharing of the component manufacturing method.

[0007] Hereinafter, these problems of sharing will be described with reference to FIG.
This will be specifically described with reference to FIG.

FIG. 4 is an enlarged view of the magnetic head section. 9a
Is a guide portion for the reference edge of the magnetic tape, which is in a spiral state in a range of about 180 degrees on the outer periphery of the fixed drum 9. The lower end of the magnetic tape runs along the guide 9a.
The height H1 from the guide 9a to the magnetic head is designed to be a constant value according to a standard magnetization pattern. Guide 9
The height H2 from a to the lower end surface of the fixed drum 9 is also designed to be a constant value. In production, the height of the magnetic head is controlled by the height from the lower end surface of the fixed drum 9 to the magnetic head (H
1 + H2 = Ho). This is the guide 9
This is because a is oblique and it is difficult to measure accurately. Hereinafter, the height of the magnetic head will be described using Ho (= H1 + H2). It should be noted that Ho in this specification corresponds to the video track because the standard magnetization pattern accurately defines the magnetization pattern of the video track. That is, it indicates the height of the video magnetic head.

FIG. 5 is an enlarged view of the surface of the magnetic head as viewed in the direction of arrow A in FIG. In FIG. 5, there is a window 3d at a position near the fixed drum 9 of the rotary drum 3a, and at a position where the magnetic head 1a slightly protrudes from the window 3d, a mounting screw is attached to the lower end surface 3c of the rotary drum 3a via a head spacer 14. 4
, The head base 2a is fastened. Magnetic head 1
A coil 1e is wound around a. 1g is a magnetic gap of the magnetic head, and is magnetically recorded on a magnetic tape by a magnetic flux leaking from the magnetic gap.

The purpose of using the head spacer 14 will be described with reference to FIGS.

FIGS. 6 and 7 show a portable VT equipped with an erasing magnetic head (flying erase head).
The case of R is shown. The reason why a rotating magnetic head device used in a portable VTR requires an erasing magnetic head (flying erase head) in the same rotating drum is as described above. Recording must be performed by the video magnetic head while erasing the already recorded signal by the erasing magnetic head.

FIG. 6 is a plan view of the arrangement of the magnetic head of the rotating drum as viewed from the fixed drum side.

Reference numeral 1c denotes an erasing magnetic head. A head base 2d as a balance weight is mounted at a symmetrical position with respect to the shaft 7 in order to obtain a dynamic balance. In the case of the popular type in which only the magnetic head for video is mounted, there is no magnetic head for erasing 1c.

In a rotary magnetic head device of a portable VTR equipped with an erasing magnetic head, the relative height between the video magnetic head and the magnetic head is set to a predetermined height in consideration of the mounting angle position of each head. Must be set to

FIG. 7 is an explanatory view showing the relative height between the video magnetic head and the erasing magnetic head of a portable VTR equipped with the video magnetic head and the erasing magnetic head.
In order to secure a relative height Hf between the reference end of the gap 1g of the video magnetic head and the reference end of the gap 1f of the erasing magnetic head 1c, the height of the video magnetic head 1a is
The erasing magnetic head 1c must have a predetermined mounting height (Hs). For this purpose, a head spacer 14 having a thickness of Hs is provided between the magnetic head for image 1a and the rotating drum 3a.
Insert That is, the height of the head base mounting surface 3c of the rotating drum 3a is increased by Hs in advance, and the thickness H
The image magnetic head 1a is lowered by the s head spacer 14, and is adjusted to a predetermined height Ho.

The problem here is a widespread type in which only a magnetic head for video is mounted.
It is necessary to remove the head spacer 14. Even if the head spacer 14 is removed, it is necessary to match the height Ho.

Conventionally, the size of the rotating drum 3a or the size of the fixed drum 9 is changed between a rotary magnetic head device equipped with a magnetic head for erasing and a rotary magnetic head device without a magnetic head for erasing. I was Conventionally, no consideration has been given to sharing these parts or sharing the manufacturing method of parts. That is, since the dimensions of the rotating drum were changed between the case with the erasing magnetic head (flying erase head) and the case without the erasing magnetic head, there was a drawback that mixed production could not be performed with the same production equipment.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is not to use a flange, which is a high-precision part, not to use a head contact terminal, which is an expensive part, and not to remove a rotor of a rotary transformer from the rotary drum. In this state, the video recording / reproducing magnetic head and the erasing magnetic head (flying erase head) can be removed and attached.

Another object of the present invention is to provide a structure in which a drum with a magnetic head for erasing and a drum without a magnetic head for erasing have the same finishing dimensions and can be mixed-produced by the same production equipment. is there.

[0020]

[Means for Solving the Problems]

(1) In a rotating magnetic head device in which recording and reproducing operations are performed on a magnetic tape wound around a part of an outer peripheral surface of a drum composed of a rotating drum and a fixed drum using a rotating magnetic head, a plurality of magnetic tapes are provided. A rotating drum equipped with a head, a fixed drum provided on its outer peripheral surface with a guide for a reference edge of the magnetic tape, and a shaft fixed to the fixed drum;
A bearing whose inner diameter side is attached to this shaft and the rotary drum is directly mounted on its outer diameter side, a rotary trans rotor and a rotary transformer stator for transmitting a signal between the rotating body and the fixed body in a non-contact manner. A magnetic head for recording and reproducing video and a magnetic head for erasing (flying erase head) are mounted in the same rotating drum, and are pulled out from a coil arranged in a rotating transformer rotor core. The tip of the coil lead wire is extended to the magnetic head portion and directly connected to the magnetic head terminal plate.

(2) In the rotary magnetic head device,
Preferably, the inner diameter of the flat opposed rotary transformer is smaller than the outer diameter of the bearing.

(3) In the rotary magnetic head device,
Preferably, the rotor of the flat opposed rotary transformer is directly fixed to the rotary drum.

(4) In the rotary magnetic head device,
Preferably, the video recording / reproducing magnetic head and the erasing magnetic head (flying erase head) are detached and attached in a state where the rotor of the flat facing rotary transformer is not detached from the rotating drum. It was made possible.

(5) In the rotary magnetic head device,
Preferably, it is used for a rotating magnetic head device of a portable magnetic recording / reproducing device.

(6) In the rotary magnetic head device,
Preferably, a first rotary magnetic head device in which a video magnetic head and an erasing magnetic head (flying erase head) are mounted on a rotary drum, and a second rotary magnetic head device in which only the video magnetic head is mounted In the above, the difference between the sum of the thicknesses of the rotary transformer rotor core and the rotary transformer stator core, which are the cores of the rotary transformers of the respective devices, is compared with the video magnetic head required in the first rotary magnetic head device. The outer dimensions of the rotary drum of the first rotary magnetic head device and the rotary drum of the second rotary magnetic head device are made to be substantially the same as the relative mounting height of the magnetic head. is there.

(7) In the rotary magnetic head device,
Preferably, the second rotary magnetic head device is used for a rotary magnetic head device of a stationary magnetic recording / reproducing device.

(8) In the rotary magnetic head device,
Preferably, the thickness of the rotary transformer rotor core, which is a component of the rotary transformer, and the thickness of the rotary transformer stator core are the same.

(9) In the rotary magnetic head device,
Preferably, the thickness of the rotary transformer rotor core and the thickness of the rotary transformer stator core of the second rotary magnetic head device are the same.

(10) In the rotary magnetic head device, it is preferable that the first rotary magnetic head device and the second rotary magnetic head device use a common rotary drum.

(11) In the rotary magnetic head device, preferably, the fixed drum of the first rotary magnetic head device and the second rotary magnetic head device are made of a common material.

(12) In the rotary magnetic head device, preferably, a spacer (shim) is used for the purpose of adjusting the clearance between the rotary transformer rotor core and the rotary transformer stator core. That is, changing the thickness of the core of the flat facing rotary transformer and changing the height of the rotary drum by changing the thickness of the clearance adjusting shim between the rotary transformer rotor core and the rotary transformer stator core. Therefore, the dimensions of the drum with the erasing magnetic head and the dimensions of the drum without the erasing magnetic head can be made the same and shared.

(13) In the rotary magnetic head device, preferably, a spacer (shim) is inserted between the video magnetic head and the rotary drum of the rotary magnetic head device.

(14) In the rotary magnetic head device, preferably, the finish processing of the rotary drums of the first rotary magnetic head device and the second rotary magnetic head device is machined by using the same lathe. .

(15) In the above rotary magnetic head device, preferably, the finish processing of the rotary drums of the first rotary magnetic head device and the second rotary magnetic head device is machined by using the same lathe. .

(16) In the rotary magnetic head device, preferably, in order to connect a signal line from the rotary transformer stator to a lower circuit, a fixed drum having an opening in a cylindrical portion of the outer peripheral portion where the magnetic tape is not wound around. A rotary magnetic head device provided with a drum, wherein a coil for a video signal is arranged on the inner diameter side and a coil for a magnetic head for erasing (flying erase head) is arranged on the outer diameter side among the coils of the flat opposed rotary transformer. It is.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The same components as those of the above-described conventional rotary magnetic head device are denoted by the same reference numerals, and detailed description thereof will be omitted, or illustration will be omitted.

FIG. 1 is a longitudinal sectional view of a rotary magnetic head device according to the present invention, and FIG. 2 is an enlarged sectional view of FIG.
FIG. 3 is a longitudinal sectional view of a rotary magnetic head device without an erasing magnetic head.

In FIG. 1, a shaft 7 is press-fitted and fixed to a fixed drum 9. On the outer periphery of the fixed shaft 7, inner diameter sides of two bearings 10a and 10b are attached.

The magnetic heads 1a and 1b are adhered and fixed to the tip of the head base 2 and fastened to the rotating drum 3a by mounting screws 4. The tips of the magnetic heads 1a and 1b slightly protrude from the outer diameter of the rotating drum 3a. The head height of the magnetic heads 1a and 1b is adjusted by a height adjusting screw 5. A printed wiring board 8 is adhered to the head base 2, and coil lead terminals from the magnetic heads 1a and 1b are provided.

The mounting bracket 6a for the motor stator is
It is fixed to the shaft 7 by a set screw 6b. A motor stator 12b is mounted on the motor stator mounting bracket 6a with mounting screws 11b.
The motor rotor 12a is mounted on the rotating drum 3a by mounting screws 11a.

A lead 13e extends from the rotary trans rotor 13a, and is connected to terminals of the printed wiring board 8 of the head base 2 by soldering.
1b and the electrical connection between the rotary trans rotor 13a.

Planar opposed rotary transformer stator 13b
Are fixed to a fixed drum 9.

The lead wire of the coil from the rotary transformer stator 13b is connected to the printed wiring board 13d and drawn out of the rotary magnetic head device.

The shaft 7 is press-fitted and fixed to a fixed drum 9, a bearing 10 is mounted on the shaft 7, and the rotary drum 3 is mounted on the outer diameter of the bearing 10.

In FIG. 2, the clearance G on the core facing surface between the rotary transformer rotor core 13k and the rotary transformer stator core 131 is adjusted by the thickness of the spacer 15a. Here, Hv indicates the dimension from the head base mounting surface of the rotary drum to the bearing, Hb is the length of the bearing, H3 is the thickness of the spacer 15a, and Hd is the dimension from the lower end surface of the fixed drum to the mounting surface of the spacer 15a. , H1 indicates the dimension from the lower end surface of the fixed drum to the rotary transformer stator core 131, and Hu indicates the dimension from the head base mounting surface of the rotary drum to the rotary transformer rotor core 13k. T1 is the thickness dimension of the rotary transformer rotor core and the rotary transformer stator core. From the relationship between the height Ho of the magnetic head and the above dimensions, the following two equations hold. 16
a · 16b is the adhesive layer but is irrelevant to the equation.

Ho = Hv + Hb + H3 + Hd-Hs Ho =
Hu + T1 + G + T1 + H1-Hs From the above equation, the following equation holds.

[0047]

## EQU1 ## Hv + Hb + H3 + Hd = Hu + T1 + G + T1 + H1 FIG. 3 is a vertical sectional view of a rotary magnetic head device without a magnetic head for erasing. Here, if the dimensions of the rotating drum and the fixed drum are the same as those of the rotating magnetic head device with the erasing magnetic head, the following two equations hold.

Ho = Hv + Hb + H4 + Hd Ho = Hu +
T2 + G + T2 + H1 From the above equation, the following equation holds.

[0049]

[Equation 2] Hv + Hb + H4 + Hd = Hu + T2 + G + T2 + H1 When the left and right sides of Equations 1 and 2 are respectively subtracted,

[0050]

H3-H4 = 2.times.T1-2.times.T2 Further, since H3-H4 = Hs is apparent from FIGS. 2 and 3, H3-H4 = 2.times.T1-2.times.T2 = Hs.

From the above, for the rotating magnetic head device with the erasing magnetic head, the thickness of the rotating transformer (the sum of the thicknesses of the rotating transformer rotor and the rotating transformer stator) is changed by the dimension Hs, and the thickness of the spacer is reduced. It is understood that Hs should be set. Further, for a rotating magnetic head device without an erasing magnetic head, the magnetic head 1a can be positioned at a predetermined height Ho without using the spacer 14.

[0052]

According to the present invention, (1) the bearing is directly mounted on the rotary drum, so that the flange which is a high precision part is not required, and the coil disposed in the rotary transformer rotor core. Extend the tip of the coil lead wire drawn out from to the magnetic head part,
The direct connection to the magnetic head terminal plate eliminates the need for expensive head contact terminals. (2) Since the inner diameter of the flat facing rotary transformer is smaller than the outer diameter of the bearing,
The rotary transformer can be downsized and cost can be reduced.

(3) Since the rotor of the flat facing rotary transformer is directly fixed to the rotary drum, there is no need for a member for mounting the rotor of the rotary transformer.

(4) As described above, since the inner diameter of the rotary transformer is reduced and the outer diameter of the rotary transformer is reduced, the magnetic head for recording / reproducing the image is reproduced without removing the rotor of the rotary transformer from the rotary drum. And the magnetic head for erasing (flying erase head) can be removed and attached.
Repair is easy.

(5) Since a magnetic head for erasing (flying erase head) can be mounted, it can be used for a rotary magnetic head device of a portable magnetic recording / reproducing apparatus.

(6) A first rotary magnetic head device in which a video magnetic head and an erasing magnetic head (flying erase head) are mounted on a rotary drum, and a second rotary magnetic device in which only a video magnetic head is mounted. In the head device,
The difference between the sum of the thicknesses of the rotary transformer rotor core and the rotary transformer stator core, which are the cores of the rotary transformers of the respective devices, is determined by the image magnetic head and the erasing magnetic required in the first rotary magnetic head device. Since the dimensions are substantially equal to the relative mounting height of the head, the outer dimensions of the rotary drum of the first rotary magnetic head device and the rotary drum of the second rotary magnetic head device can be made common.

(7) The second rotary magnetic head device can be used for a rotary magnetic head device of a stationary magnetic recording / reproducing device, and can have the same outer dimensions as a rotary drum of a portable magnetic recording / reproducing device.

(8) (9) The thickness of the rotary transformer rotor core, which is a component of the rotary transformer, and the thickness of the rotary transformer stator core can be made the same, and the machining of the rotary transformer core can be shared.

(10) First rotating magnetic head device and second rotating magnetic head device
The material of the rotating drum of the rotating magnetic head device can be shared.

(11) First rotating magnetic head device and second rotating magnetic head device
The material of the fixed drum of the rotary magnetic head device can be shared.

(12) A spacer (shim) is used for adjusting the clearance between the rotary transformer rotor core and the rotary transformer stator core. That is, changing the thickness of the core of the flat facing rotary transformer and changing the height of the rotary drum by changing the thickness of the clearance adjusting shim between the rotary transformer rotor core and the rotary transformer stator core. Therefore, the dimensions of the drum with the erasing magnetic head and the dimensions of the drum without the erasing magnetic head can be made the same and shared.

(13) A spacer (shim) is provided between the rotating magnetic drum and the image magnetic head of the rotating magnetic head device.

(14) (15) Portable V equipped with an erasing magnetic head (flying erase head)
In the finishing processing of the TR drum and the drum without the erasing magnetic head (rotary drum and fixed drum), mixed production can be performed with the same production equipment.

(16) In a rotary magnetic head device provided with a fixed drum having an opening in a cylindrical portion of an outer peripheral portion of a drum with no magnetic tape wound thereon, a video signal coil is provided on an inner diameter side of the coils of the flat opposed rotary transformer. And a coil for an erasing magnetic head (flying erase head) is arranged on the outer diameter side, thereby making it difficult to receive external disturbance noise.

The present invention produces the following economic effects by the following direct effects. That is, since the rotating transformer rotor core and the rotating transformer stator core can have the same thickness and can share the core, changing the thickness of the core does not increase the cost.

Further, since the material of the drum of the portable VTR on which the erasing magnetic head is mounted and the material of the drum without the erasing magnetic head can be shared, a cost reduction effect is produced.

Changing the thickness of the spacer for the purpose of adjusting the clearance between the rotary transformer rotor core and the rotary transformer stator core does not increase the cost. In a rotary magnetic head device of a portable VTR equipped with a magnetic head for erasing, a head spacer is provided between the magnetic head for video and the rotary drum to adjust the height between the magnetic head for video and the rotary drum. Entering is the cheapest method.

The greatest effect is that the same production equipment can be used for finishing the drum of the portable VTR on which the erasing magnetic head is mounted and the drum without the erasing magnetic head. In addition, since there is no machine setup change even in mixed production, continuous production is possible and the high operation rate of the machine can be maintained.

Although the above description has been given as a rotary magnetic head device applied to a portable VTR equipped with an erasing magnetic head, even in a stationary VTR, an erasing magnetic head is mounted on a VTR with an editing function. Therefore, the first rotating magnetic head device of the present invention is not limited to a portable VTR.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rotary magnetic head device according to the present invention.

FIG. 2 is an enlarged sectional view of FIG.

FIG. 3 is a longitudinal sectional view of a rotary magnetic head device without an erasing magnetic head.

FIG. 4 is an enlarged longitudinal sectional view of a magnetic head portion of the rotary magnetic head device.

FIG. 5 is an enlarged view of the surface of the magnetic head as viewed in the direction of arrow A in FIG. 4;

FIG. 6 is a plan view of the arrangement of the magnetic head of the rotating drum as viewed from the fixed drum side.

FIG. 7 is an explanatory diagram showing a relative height between a video magnetic head and a magnetic head for erasing of a rotary magnetic head device for a portable VTR with a television camera on which the magnetic head for video and a magnetic head for erasing are mounted. .

[Explanation of symbols]

 1a, 1b: magnetic head for video, 1c: magnetic head for erasing, 1e: coil, 1f, 1g: magnetic gap, 2a, 2c: head base, 2d: head base, 3a: rotating drum, 3b: rotating drum, 3c ... lower end surface, 3d ... window, 4 ... mounting screw, 5 ... height adjusting screw, 6a ... mounting bracket, 6b ... set screw, 7 ... shaft, 8 ... printed wiring board, 9 ... fixed drum, 9a ... guide part, DESCRIPTION OF SYMBOLS 10 ... Bearing, 11a ... Motor rotor mounting screw, 11b ... Motor stator mounting screw, 12a ... Motor rotor, 12b ... Motor stator, 13a ... Rotating transformer rotor, 13b ... Rotating transformer stator, 13c ... Rotating transformer rotor, 13d ... Rotating transformer Stator, 13e Leader, 13i Flexible printed circuit board, 13k Rotating transformer rotor core, 13l rotating transformer stator core, 13m rotating transformer rotor core, 13n rotating transformer stator core, 13o coil, 13p coil, 14 head spacer, 15a spacer, 15b spacer, 16a bonding Layer, 16b ... adhesive layer.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tsuneori Iwama 1410 Inada, Hitachinaka-shi, Ibaraki Pref., Hitachi, Ltd. Visual Information Media Division (72) Inventor Makoto Ibe 1410 Inada, Hitachinaka-shi, Ibaraki Hitachi, Ltd. Media Division (72) Inventor Toshio Nagata 1410 Inada, Hitachinaka City, Ibaraki Prefecture Hitachi, Ltd. Video Information Media Division

Claims (16)

[Claims] 1. A rotary magnetic head device for performing a recording / reproducing operation using a rotary magnetic head on a magnetic tape wound around a part of an outer peripheral surface of a drum composed of a rotary drum and a fixed drum. A rotating drum on which a magnetic head is mounted, a fixed drum provided on its outer peripheral surface with a guide portion for a reference edge of a magnetic tape, a shaft fixed to the fixed drum, and an inner diameter side attached to the shaft. A bearing having the rotary drum directly mounted on the outer diameter side thereof, a flat facing rotary transformer including a rotary transformer rotor and a rotary transformer stator for transmitting a signal between the rotary body and the fixed body in a non-contact manner; A magnetic head for recording / reproducing and a magnetic head for erasing (flying erase head) are mounted on the same rotating drum, and a coil disposed in a rotating trans rotor core. The previous drawn coil lead wire extended to the magnetic head unit, rotary magnetic head apparatus being characterized in that and connect directly to the magnetic head terminal plate. 2. The flat-type rotary transformer according to claim 1, wherein two of said bearings are arranged vertically with respect to said shaft, and said position of said flat-type rotary transformer is located outside said two bearings. A rotating magnetic head device having an inner diameter smaller than an outer diameter of the bearing. 3. The rotary magnetic head device according to claim 1, wherein the rotor of the flat facing rotary transformer is directly fixed to the rotary drum. 4. The magnetic recording / reproducing magnetic head and the erasing magnetic head (flying erase head) according to claim 1, wherein the rotor of the flat facing rotary transformer is not removed from the rotary drum. A rotary magnetic head device characterized in that it can be mounted. 5. A rotary magnetic head device wherein the rotary magnetic head device according to claim 1 is used for a rotary magnetic head device of a portable magnetic recording / reproducing apparatus. 6. A first rotating magnetic head device according to claim 1, wherein said rotating magnetic head device in which said video recording / reproducing magnetic head and said erasing magnetic head (flying erase head) are mounted on said rotating drum. A rotary magnetic head device not equipped with the erasing magnetic head (flying erase head) but mounted only with the video recording / reproducing magnetic head is referred to as a second rotating magnetic head device, and a rotary transformer core of each device is provided. The difference between the sum of the thicknesses of the rotary transformer rotor core and the rotary transformer stator core is determined by the relative distance between the video recording / reproducing magnetic head and the erasing magnetic head required in the first rotary magnetic head device. The outer dimensions of the rotating drum of the first rotating magnetic head device and the second Rotary magnetic head apparatus being characterized in that to the external dimensions of the rotary drum of the magnetic head device in common. 7. A rotary magnetic head device according to claim 6, wherein said second rotary magnetic head device is used for a rotary magnetic head device of a stationary magnetic recording / reproducing apparatus. 8. The rotary magnetic head device according to claim 1, wherein the thickness of the rotary transformer rotor core and the thickness of the rotary transformer stator core, which are components of the rotary transformer, are the same. 9. The rotary magnetic head device according to claim 6, wherein the thickness of the rotary transformer rotor core and the thickness of the rotary transformer stator core of the second rotary magnetic head device are the same. 10. The rotary magnetic head device according to claim 6, wherein a material of a rotary drum of the first rotary magnetic head device and a material of a rotary drum of the second rotary magnetic head device are common. 11. The rotary magnetic head device according to claim 6, wherein a material of a fixed drum of said first rotary magnetic head device and a material of a fixed drum of said second rotary magnetic head device are common. 12. The rotary magnetic head device according to claim 1, wherein a spacer (shim) is used for adjusting a clearance between the rotary transformer rotor core and the rotary transformer stator core. 13. A spacer according to claim 1, wherein a spacer (shim) is provided between said magnetic head for recording and reproducing video and said rotary drum.
A rotary magnetic head device comprising: 14. The rotating magnetic head according to claim 6, wherein the finishing of the rotating drums of the first rotating magnetic head device and the second rotating magnetic head device is machined using the same lathe. Head device. 15. The rotating magnetic device according to claim 6, wherein the fixed drums of the first rotating magnetic head device and the second rotating magnetic head device are machined using the same lathe. Head device. 16. A fixed drum according to claim 1, further comprising: a fixed drum having an opening in a cylindrical portion of an outer peripheral portion of the fixed drum which is not wound with a magnetic tape for connecting a signal line from the rotary transformer stator to an external circuit. In the rotary magnetic head device, a video recording / reproducing coil is arranged on the inner diameter side of the coil of the flat opposed rotary transformer, and a coil for erasing magnetic head (flying erase head) is arranged on the outer diameter side. Rotating magnetic head device.