JPH0963001A - Manufacture of rotary magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a rotary magnetic head having an FM audio signal recording/reproducing function and a rotary magnetic head device drum having no FM audio signal recording/reproducing function in the same manufacturing facility in a mixed manner. SOLUTION: To manufacture two kinds of rotary magnetic head devices in the same manufacturing facility in a mixed manner by changing the thickness of cores 13m and 13n of rotary transformers and sharing a rotary drum 3b and a fixed drum 9. Thus, manufacturing efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rotary magnetic head device used in a magnetic recording / reproducing device such as a VTR.

[0002]

2. Description of the Related Art A conventional rotary magnetic head device is disclosed in Japanese Patent Laid-Open No.
As described in JP-A-162410, a minimum of two (one set) magnetic heads for video signals are mounted on the upper drum (rotating drum). Although not described in this publication, in a VHS standard VTR, a high-class VTR in which two (one set) FM audio signal magnetic heads are additionally mounted in addition to a video signal magnetic head is produced. There is. A VTR equipped with only a video signal magnetic head is also manufactured as a popular type.

When these high-quality type and popular type VTRs are produced in parallel, it is desirable to share parts and common parts manufacturing methods.

The problem of sharing these parts and common parts manufacturing method will be described below in detail with reference to FIGS.

FIG. 3 is a vertical sectional side view of a conventional rotary magnetic head device used for a VTR. Magnetic heads 1a, 1
b is adhesively fixed to the tip of the head base 2 and fastened to the rotary drum 3 a by the mounting screw 4. The tips of the magnetic heads 1a and 1b slightly project from the outer peripheral surface of the rotary drum 3a. Reference numeral 5 is a height adjusting screw for adjusting the head height. Mounting bracket for motor stator 6a
Is a shaft 7 fixed to a fixed drum 9 by a set screw 6b.
It is fixed to. Reference numeral 8 is a printed wiring board adhered to the head base 2a, and is provided with coil lead wire terminals from the magnetic heads 1a and 1b.

10 is a bearing, 12a is a motor rotor,
12b is a motor stator, 11a is a motor rotor mounting screw, and 11b is a motor stator mounting screw.

The rotary transformer rotor 13a and the rotary transformer stator 13b constitute an axially plane opposed type rotary transformer which performs signal transmission between the rotary portion and the fixed portion in a non-contact manner, and the coil lead wire 1 from the rotary transformer rotor 13a.
3e is connected to the terminals of the printed wiring board 8 of the head base 2 by soldering. Rotating transformer stator 13b
Is a flexible printed wiring board 13i.
And is drawn out of the rotary magnetic head device.

FIG. 4 is an enlarged view of the magnetic head portion in FIG. Reference numeral 9a is a guide portion for the reference edge of the magnetic tape, which is formed in a spiral state on the outer peripheral surface of the fixed drum 9 within a range of about 180 degrees, and runs along the lower end edge of the magnetic tape along the guide portion 9a. Let The height H1 from the guide portion 9a to the magnetic heads 1a and 1b is designed to be a constant value so as to meet the standard of the magnetization pattern for the magnetic tape. The height H2 from the guide portion 9a to the lower end surface of the fixed drum 9 is also designed to be a constant value.

In the production process, the height of the magnetic head is controlled by measuring the height (H1 + H2 = Ho) from the lower end surface of the fixed drum 9 to the magnetic head.
This is because it is difficult to measure accurately because the guide portion 9a is inclined. Hereinafter, the height of the magnetic head will be described using Ho (= H1 + H2). Since the magnetization pattern of the standard accurately defines the magnetization pattern of the video track, Ho in this case corresponds to the video track. That is, it indicates the height of the magnetic head for video signals.

FIG. 5 is an enlarged view of the outer peripheral surface near the magnetic head of FIG. The head window 3b is formed at a position close to the fixed drum 9 of the rotary drum 3a, and the head base 2a interposes the head spacer 14 so that the tip of the magnetic head 1a is positioned slightly protruding from the head window 3b. Let the rotating drum 3a
It is fastened to the lower end surface 3c of the with a mounting screw 4. A coil 1e is wound around the magnetic head 1a. Reference numeral 1g is a magnetic gap of the magnetic head, and magnetic recording is performed on the magnetic tape by the leakage magnetic flux from the magnetic gap 1g.

The purpose of using the head spacer 14 will be described with reference to FIGS. 6 and 7. 6 and 7 exemplify a rotary magnetic head device of a VTR capable of recording / reproducing an FM audio signal of VHS standard. 6 is a sectional view taken along line VI-VI of FIG.

Reference numerals 1c and 1d denote FM audio signal magnetic heads. A popular VT equipped with only a magnetic head for video signals
The R rotary magnetic head device does not include the FM audio signal magnetic heads 1c and 1d. The rotary magnetic head device of the high-end type VTR capable of recording and reproducing the VHS standard FM audio signal has a magnetic head 1d for the FM audio signal magnetically recording the audio signal to a deep portion of the magnetic tape in the first field, and then recording on the recorded track. The video signal magnetic head 1a records a video signal of a short wavelength on a layer near the surface of the magnetic tape. In the next field, the FM audio signal magnetic head 1c records the audio signal, and then the video signal magnetic head 1b records the video signal on the recorded track. Then, these signal recordings are sequentially repeated.

In the standardized magnetization pattern, the relative height between the video signal track and the FM audio signal track is also set to a predetermined height. Therefore, even in the rotary magnetic head device, the mounting angular position of each head is determined. Considering this, the relative height between the video signal magnetic head and the FM audio signal magnetic head must be set to a predetermined height.

FIG. 7 shows the relative heights of the magnetic head for video signals and the magnetic head for FM audio signals. In order to secure a relative height Hf between the reference end of the gap 1g of the video signal magnetic head 1a and the reference end of the gap 1f of the FM audio signal magnetic head 1d, the relative height Hf is set with respect to the height of the video signal magnetic head 1a. The FM audio signal magnetic head 1d must be positioned at a predetermined mounting height (Hs). Therefore, a head spacer 14 having a thickness Hs is inserted between the video signal magnetic head 1a and the rotary drum 3a. That is,
The height of the head base mounting surface 3c of the rotating drum 3a is raised by Hs in advance, and the mounting position of the video signal magnetic head 1a is lowered by the head spacer 14 having the thickness Hs so as to match the predetermined height Ho. ing.

The problem here is that if the head spacer 14 is to be removed in order to reduce the manufacturing cost of the rotary magnetic head device equipped with only the magnetic head for video signals used in the popular type VTR, the video signal will be lost. The mounting position of the magnetic head 1a for use does not match the height Ho. For this reason, conventionally, the rotary magnetic head device without the FM audio signal recording / reproducing function is different from the rotary magnetic head device with the FM audio signal recording / reproducing function in that the size of the rotary drum 3a is changed or the fixed drum 9 is used. The size is changed.

[0016]

Various types of VTRs have been produced, ranging from popular types to high-grade types. In the prior art, the components of each rotary magnetic head device used in these VTRs are commonly used. There is no consideration for sharing manufacturing methods. That is, the rotary magnetic head device having the FM audio signal recording / reproducing function and the rotary magnetic head device having no FM audio signal recording / reproducing function cannot be mixedly produced in the same production facility because the size of the rotary drum 3a is changed. was there.

An object of the present invention is to enable mixed production of a drum of a rotary magnetic head device with an FM audio signal recording / reproducing function and a drum of a rotary magnetic head device without an FM audio signal recording / reproducing function in the same production facility. To do.

[0018]

SUMMARY OF THE INVENTION In order to achieve the object of the present invention, by changing the thickness of a rotary transformer core of a plane-opposed rotary transformer, a rotary drum and a fixed drum can be shared and two types of rotary magnetic fields can be obtained. The head device is manufactured by using a common production facility.

[0019]

Since the height of the rotary drum can be changed by changing the thickness of the core of the plane-opposing rotary transformer, the rotary magnetic head device with the FM voice signal recording / reproducing function and the rotary magnetic head without the FM voice signal recording / reproducing function are provided. The drum size of the apparatus can be made common and common.

[0020]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. The same components as those of the conventional rotary magnetic head device described above are designated by the same reference numerals, and detailed description thereof will be omitted, or description thereof will be omitted.

FIG. 1 is a vertical sectional side view of a rotary magnetic head device having an FM audio signal recording / reproducing function according to the present invention. The spacer 15a adjusts the gap G between the core facing surfaces of the rotary transformer rotor core 13k and the rotary transformer stator core 13l by its thickness.

Reference numeral 13k is a rotary transformer rotor core, 13l is a rotary transformer stator core, 13o is a stator coil, and 13p is a rotor coil.

Here, Hv is the dimension from the head base mounting surface 3c of the rotary drum 3a to the bearing 10, Hb is the length of the bearing 10, H3 is the thickness dimension of the spacer 15a, and Hd is the reference lower end surface of the fixed drum 9. Dimension to the mounting surface of the spacer 15a, Hl is the dimension from the reference lower end surface of the fixed drum 9 to the rotary transformer stator core 13l, Hu is the dimension from the head base mounting surface 3c of the rotary drum 3a to the rotary transformer rotor core 13k, T1 Is a rotary transformer rotor core 13k and a rotary transformer stator core 13l
Is the thickness dimension of.

The following two equations are established from the relationship between the height Ho from the reference lower end surface of the fixed drum 9 to the magnetic head 1a and each of the above dimensions. Note that although 16a and 16b are adhesive layers, they are irrelevant to the equation.

Ho = Hv + Hb + H3 + Hd-Hs Ho = Hu + T1 + G + T1 + Hl-Hs From these two equations, the following equation holds.

Hv + Hb + H3 + Hd = Hu + T1 + G + T1 + Hl (Equation 1) FIG. 2 is a vertical cross-sectional side view of the rotary magnetic head device without the FM audio signal recording / reproducing function, and the height of the magnetic head 1a is set to Ho without using the head spacer (14). The conditions for matching are explained. In addition, 13c is a rotary transformer, 1
3d is a rotary transformer stator, 13m is a rotary transformer rotor core, and 13n is a rotary transformer stator core.

If the rotary drum 3a and the fixed drum 9 are of the same size as the rotary magnetic head device with the FM audio signal recording / reproducing function described above, the following two equations hold.

Ho = Hv + Hb + H4 + Hd Ho = Hu + T2 + G + T2 + Hl From these two equations, the following equation holds.

Hv + Hb + H4 + Hd = Hu + T2 + G + T2 + Hl (Equation 2) Next, when the left and right sides of (Equation 1) and (Equation 2) are respectively subtracted, H3−H4 = 2 × T1-2 × T2 (Equation 3) Further, H3− H4 = 2 * T1-2 * T2 = Hs.

Therefore, the thickness of the rotary transformer (the sum of the thickness of the core 13m of the rotary transformer rotor 13c and the thickness of the core 13n of the rotary transformer stator 13d) is changed by the dimension Hs, and the thickness of the spacer 15b is changed by the dimension Hs. The magnetic head 1a can be positioned at the predetermined height Ho even if the rotary drum 3b having the same size and shape as the rotary drum 3a is used and the head spacer (14) is omitted.

[0031]

According to the present invention, the drum of the rotary magnetic head device used in the VTR having the FM audio signal recording / reproducing function and the drum of the rotary magnetic head device used in the VTR having no FM audio signal recording / reproducing function are made of a common material. It is possible to increase the productivity and reduce the manufacturing cost by carrying out mixed production with the same production equipment using. In particular, even in finishing processing using the same lathe as the processing machine for the rotary drum and the fixed drum, it is not necessary to change the setup of the processing machine, so that a high production rate of the processing machine can be maintained by continuous production.

Further, since the rotary transformer rotor core and the rotary transformer stator core can have the same thickness and share the core, changing the thickness of the core does not increase the cost.

Further, changing the thickness of the spacer for the purpose of adjusting the gap between the rotary transformer rotor core and the rotary transformer stator core is the same as the conventional one, and the cost does not increase.

Furthermore, in a rotary magnetic head device used in a VTR having an FM audio signal recording / reproducing function, in order to adjust the height between the video signal magnetic head and the rotary drum, the video signal magnetic head and the rotary drum are separated. Inserting a head spacer in between is the cheapest method.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a rotary magnetic head device with an FM audio signal recording / reproducing function according to the present invention.

FIG. 2 is a vertical sectional side view of a rotary magnetic head device without an FM audio signal recording / reproducing function according to the present invention.

FIG. 3 is a vertical sectional side view of a conventional rotary magnetic head device.

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

5 is an enlarged view of the outer peripheral surface of the magnetic head when the rotary magnetic head device in FIG. 3 is viewed in the direction of arrow A. FIG.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is an explanatory diagram showing relative heights of a magnetic head for video signals and a magnetic head for FM audio signals.

[Explanation of symbols]

1a, 1b ... Magnetic heads for video signals, 1c, 1d ... FM
Magnetic heads for audio signals, 2a ... Head base, 2d ... Head base, 3a ... Rotating drum, 3b ... Rotating drum, 4
… Mounting screws, 5… Height adjusting screws, 7… Shafts, 9… Fixed drums, 10… Bearings, 13a… Rotary transformers, 1
3b ... rotary transformer stator, 13c ... rotary transformer rotor, 13d ... rotary transformer stator, 13k ...
Rotating transformer rotor core, 13l ... Rotating transformer stator core, 13m ... Rotating transformer rotor core, 13
n ... Rotating transformer stator core.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Oh ▼ Toshio Ji 1410 Inada, Hitachinaka City, Ibaraki Prefecture Incorporated company Hitachi, Ltd. Personal Media Equipment Division (72) Shinji Ozaki 1410 Inada, Hitachinaka City, Ibaraki Prefecture Incorporated company Hitachi, Ltd. Personal Media Equipment Division (72) Inventor Keisuke Iwama 1410 Inada, Hitachinaka City, Ibaraki Prefecture Incorporated Hitachi, Ltd. Personal Media Equipment Division (72) Inventor, Kuniaki Hirayama 1410 Inada, Hitachinaka City, Ibaraki Prefecture Incorporated company Hitachi, Ltd. Personal Media Equipment Division (72) Inventor Yoshio Uemura 1410 Inada, Hitachinaka City, Ibaraki Prefecture Hitachi Ltd. Personal Media Equipment Division (72) Inventor Toshihiko Imachi Ibaraki 1410 Inada, Hitachinaka-shi, Japan Incorporated company Hitachi, Ltd. Personal media equipment division

Claims (12)

[Claims] 1. A magnetic tape wound on a part of an outer peripheral surface of a drum composed of a rotary drum and a fixed drum is recorded and reproduced by using a magnetic head provided on the rotary drum to rotate the magnetic tape. In a method of manufacturing a rotary magnetic head device in which signal transmission between a fixed portion and a fixed portion is performed in a non-contact manner by a plane-opposing rotary transformer, a first magnetic head for FM audio signals and a magnetic head for video signals are mounted on a rotary drum. The difference between the thicknesses of the rotary transformer cores of the rotary magnetic head device and the second rotary magnetic head device, in which only the magnetic head for video signals is mounted, is used for the FM audio signal required in the first rotary magnetic head device. The size is set to be approximately equal to the relative mounting height of the magnetic head and the video signal magnetic head, and the external dimensions of the rotary drum of the first rotary magnetic head device and the rotation of the second rotary magnetic head device are set. 2. A method for manufacturing two types of rotary magnetic head devices, which is characterized in that the outer dimensions of a rolling drum are made common. 2. A rotary magnetic head device in which a recording / reproducing operation is performed by using a rotary magnetic head on a magnetic tape wound on a part of an outer peripheral surface of a drum composed of a rotary drum and a fixed drum. A plane in which a plurality of magnetic heads are mounted on a drum and a shaft is fixed to a fixed drum having a guide portion for the reference edge of the magnetic tape on the outer peripheral surface, and signals are transmitted between the rotating body and the fixed body in a non-contact manner. A first rotary magnetic head device having an opposed rotary transformer, in which an FM audio signal magnetic head and a video signal magnetic head are mounted on a rotary drum, and a second rotary magnetic head in which only a video signal magnetic head is mounted. The difference in the thickness of each rotary transformer core of the device is approximately equal to the relative mounting height of the FM audio signal magnetic head and the video signal magnetic head required in the first rotary magnetic head device. A method for manufacturing two types of rotary magnetic head devices, wherein the fixed drum of the first rotary magnetic head device and the fixed drum of the second rotary magnetic head device have the same outer dimensions. 3. The method of manufacturing a 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 of the first rotary magnetic head device are the same. 4. The method of manufacturing a 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 of the second rotary magnetic head device are the same. 5. The method of manufacturing a rotary magnetic head device according to claim 1, wherein the rotary transformer rotor core and the rotary transformer stator core of the first rotary magnetic head device are made common. 6. The method of manufacturing a rotary magnetic head device according to claim 1, wherein the rotary transformer rotor core and the rotary transformer stator core of the second rotary magnetic head device are shared. 7. The method of manufacturing a rotary magnetic head device according to claim 1, wherein the materials of the rotary drum in the first rotary magnetic head device and the second rotary magnetic head device are common. 8. A method of manufacturing a rotary magnetic head device according to claim 2, wherein the materials of the fixed drum in the first rotary magnetic head device and the second rotary magnetic head device are common. 9. A method of manufacturing a rotary magnetic head device according to claim 2, wherein a gap between the rotary transformer rotor core and the rotary transformer stator core is adjusted by a spacer. 10. A method of manufacturing a rotary magnetic head device according to claim 1, wherein a spacer is inserted between the video signal magnetic head and the rotary drum in the first rotary magnetic head device. 11. The rotary magnetic head device according to claim 1, wherein the rotary drums of the first rotary magnetic head device and the second rotary magnetic head device are machined by using the same lathe. Manufacturing method. 12. The rotary magnetic head device according to claim 1, wherein the fixed drums of the first rotary magnetic head device and the second rotary magnetic head device are machined using the same lathe. Manufacturing method.