JPH01264625A - Rotary head device - Google Patents

Abstract

PURPOSE:To cause a construction to be thin and to obtain a thinness and a compactness as a whole by providing a concave part to house a rotary part in the bottom surface part of a guide drum. CONSTITUTION:A concave part 600 is provided in the lower side part on the bottom surface of a power guide drum 3 for a tape 400 traveling, and a motor for a direct-coupled drive is arranged inside it. Thus, the size and construction of a device can be made thin, light-weight and, simultaneously, compact. Since an incorporating work can be executed in always maintaining a device attitude in an erecting condition in the assembling process of the device, the work can be made easy to execute. Further, cylindrical rotary transformers 14 and 15 are used. For such a reason, a space for the transformers in the drum 3 can be reduced, and simultaneously, the crosstalk of a signal can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a rotary head device such as a video tape recorder (yrR), and particularly to a structure that is easy to assemble and is suitable for miniaturization.

[Conventional technology]

A conventional example of a device structure in which a motor installed outside the bottom of the lower guide drum rotates the center shaft is the Utility Model 57-0.
There is a structure described in No. 05.

[Problem that the invention seeks to solve]

The above conventional technology does not take into account improvements in device assembly workability, thinning, etc., and has the problem that it is not optimal for automating assembly work in mass production, miniaturizing sets for mounting this device such as VTRs, etc. ◇ An object of the present invention is to overcome these drawbacks of the prior art and to provide a rotary head device that is thin, easy to assemble, and capable of improving performance.

[Means for solving problems]

In order to achieve the above object, the rotary head device of the present invention includes a recessed portion for storing a rotating portion such as a direct drive motor at the lower bottom of the +11 lower guide drum. 2) A cylindrical transformer is used as the rotary transformer.

[Effect]

By providing a recess on the bottom of the lower guide drum concentrically with respect to the center axis, the drive motor including the rotor and stator can be stored in this recess, so the motor part protrudes outside the outer shape of the rotating head device. There's nothing to do. Therefore, this device has a small and compact structure as a whole. Furthermore, in the assembly process, the drum can always be kept in an upright position even when the motor etc. are installed, making the assembly process easy and the process easy to automate.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

FIGS. 1 and 2 are diagrams showing a first embodiment of the rotary head device of the present invention, and are an example of the structure of a rotary head device for a VTR.

FIG. 1 is a longitudinal sectional view, and FIG. 2 is a system configuration diagram. In this embodiment, the lower guide drum 5 for running the tape 400 is
A recessed portion 600 is provided at the lower side of the bottom surface of the recessed portion 600, and a direct-coupled drive motor is disposed within this recessed portion 600. 1 is the rotation center axis, 5.5' is the bearing, 18 is the motor rotor magnet, 21 is the motor stator coil (the motor system is a 3-phase brushless motor, and the coil connection is star-shaped), 25 is the motor fixing A child wiring board, 40 a position sensor, 41 a head position detection sensor (
45 is the same magnet (tack magnet), 22 is a rotary yoke with a structure that rotates integrally with the magnet 18, 70 is a magnet for frequency signal generation for speed detection (FG Magneno), 24 is a frequency signal generator board (FG board), 71 is the same yoke (FG yoke), 55
5 is a ground holder for electrically grounding the rotating shaft; 1
4.15 is a cylindrical rotary transformer for transmitting the recording percentage of the head 100 to raw signals, 14' and 15' are flat rotary transformers, 28 is a transformer substrate, 95 is a magnetic material plate for shielding, and 107 is a Fixed side amplifier circuit, 75 is a disk structure for mounting and fixing the upper drum 2 with high precision, 2
7 is a substrate, 82 is a magnetic material plate, 104α, 104b is a control signal forming section of the switch circuit 102, 100 is a head,
900 is an electric-to-mechanical converter such as a piezoelectric material for controlling the position of the head 100 according to a control signal; 26 is a substrate; 10
1 is a rotation side reproduction signal amplification circuit, 102 is a switch circuit for switching between recording and reproduction modes and head switching, 350 is a conductor pin for connecting the substrate 26 and substrate 27, 210 is a slip ring structure, 200 is a slip ring, 201 is a brush, 204 is a support arm for supporting the brush fixing piece 204, and 12 is a screw for tightening. The central shaft 1 is fixed at its upper end to the center of the disk assembly. In the brush 201° slip ring 200, the circuits 101 and 10 mounted on the rotating structure
2,104gt 104b and the head control electric-to-mechanical conversion section 900. The head 100 is fixed on the converting section 900, and the converting section 900 is fixed to the lower surface of the upper drum 2 and rotated together with the disk 75. The brush fixing piece 204 is attached to the upper support piece 750 with a screw 12.
By adjusting this fixed position, the contact attitude of the brush 201 with respect to the slip ring 200 can be adjusted as appropriate. On the board 25, terminal connections of the stator coil 21 and wiring and fixing of the sensor 940.41 are performed, and on the board 28, the rotary transformer 14.・15.14
15', the terminals of the channel coils in the fixed yoke 14.14' are connected and the wiring of the fixed amplifier 107 is fixed, and on the board 26, the terminals of the channel coils in the fixed side yoke 14. Channel coil terminal connection, slip ring 200 and circuits 101, 102, 10
Connects with 4α and 104h.

The outline of the operation of this structural device is as follows. That is, the disk structure is supported on the upper part of the lower guide drum 5 by controlling the motor stator coil 21 to be energized from a separately provided motor control circuit and drive circuit to rotate the motor rotor, and via a rotating shaft directly connected to the motor stator coil 21. 75. Upper drum 21 rotating transformer yoke 15°15', slip ring structure 21
A first rotating body consisting of 0, etc. is rotated. This causes the head 100 to scan the surface of the tape 4000 running on the sides of the upper and lower drums 2 and 3 to record or reproduce a video signal. The rotational speed and phase of the head are controlled by controlling the rotation of the motor. In other words, the rotational speed is determined by the frequency signal (F
A speed pubo signal is formed from the G times signal, and the coil power supply to the φ drive circuit is controlled by this signal.

Further, the rotational phase is controlled by comparing a control tack signal formed from the output signal of the tack sensor with a reference signal to generate an error signal, and controlling the coil power supply by the drive circuit in the same way as in the case of speed control.

For information on how to process video signals during recording and playback, see Part 2.
This will be explained with a diagram. That is, during recording, the signals amplified by fixed side amplifiers 107A and 107d are transmitted to the rotary body side by rotary transformers 14, 15, 14' and 15', and heads 100α, 100α, fixed to the outer periphery of the upper drum are transmitted.
.

100A, , and 100b2 to excite them and record on the tape surface. At this time, the switch RFC in the figure is kept in the on state. On the other hand, during playback, head 10
0(11, 100α2, 100b1, 100b2 is an amplifier 101a mounted on the rotating body side for the signals reproduced from the tape 400.

After being amplified by 101b, 101c, and 101d, the signals are transmitted to the fixed side by rotary transformers 15.14, 15', and 14', further amplified by amplifiers 107a and 107c on the fixed side, and transmitted to a subsequent signal processing circuit such as a demodulation circuit. Switch H in the figure,
is a pair of heads 100al and 1007 for head switching.
12, 100b1 and 100A2 in each pair every 20 half rotations of the upper drum. Amplifiers 101α and 101b.

101(!, 101d, switch circuit 102 and control signal forming unit 104σ, 104b are supplied with operating power through slip ring 200+z, 200b and brush 20.
1 (1, via 201A. Also, the original signal for control signal is transmitted using the channel in the rotating transformer (1
4c, 15c). Furthermore, during playback, electrical to mechanical converters 900α and 900h19, such as piezoelectric materials, fixed each head.
00c and 900d to perform tracking control for each head. As described above, according to the structure of this embodiment, (1) since the drive motor is housed in the recess at the bottom of the lower guide drum, the axial height of the rotary head device can be reduced, resulting in a thin structure; can.

(2) During the device assembly process, the device can be assembled while always keeping the device in an upright position, which makes the work easier and there is extremely little risk of damaging the drum surface, motor, head, and other built-in parts. It is also easy to automate assembly work, making it suitable for mass production. (3) Since a cylindrical rotary transformer 14.15 is used, the space for the transformer within the drum can be reduced, signal crosstalk can be significantly reduced, and performance variations between channels can be suppressed.

Also, multi-channel signal transmission is easily possible.

(4) The bottom part of the lower drum 6 can be made thinner and lighter. (5) Since the length of the central shaft 1 can be shortened, the torsional natural frequency of the shaft 1 can be increased and torsional vibrations when the head rotates can be suppressed. This suppresses uneven rotation of the head rotor, lowers the jitter value, and provides a clear image.

FIG. 5 is a sectional view ((α)) of the second embodiment of the device of the present invention.
and a cross-sectional view ((b)) of the third embodiment. Same figure (α)
18 is a sectional view showing an example of a structure in which the yoke 22 of the motor is fixed and fixed to the bottom view of the stator coil 21, and FIG. 18' is a cross-sectional view of a configuration example in which a stator coil 21 and a substrate 25 are sandwiched and fixed between magnetic pole faces using a magnet. In (b), 70 is an FG magnet. The structure of other parts is the same as that of the first embodiment. The bookcase 2 and the third embodiment have almost the same advantages as the first embodiment.

FIG. 4 is a sectional view of a fourth embodiment of the device of the present invention.
-Compared to the third embodiment, the bottom surface of the lower drum 5 is shifted upward, and the depth of the lower recess is increased upward. 1
6 and 28 are boards for connecting the coil terminals of the transformer 14;
350 is a conductor bin for connection between side boards, and 95 is a magnetic material plate for magnetic shielding.

The FG magnet 70 has a yoke 1 on the inner circumference of the magnet 18.
9 is provided so as to protrude, and the substrate 25 is also used as an FG substrate. The configuration of other parts is the same as in the first to fifth embodiments. In this embodiment, the recess 600 is the tape guide of the drum 5. The lower end of the rotary transformer 14.15 is deep enough to reach the height of the guide end surface 701, and the lower end of the rotary transformer 14.15 is
Magnetic material plate 95. It is provided downwardly from the substrate 28 and at a height position protruding toward the recess. According to the structure of this embodiment, the axial dimension of the lower guide drum B can be made thinner, and the length of the central shaft 1 can be further shortened. Therefore, by adopting the configuration of this embodiment, the overall thickness of the device can be further reduced.

It is possible to reduce weight, improve shaft torsional vibration characteristics, and reduce jitter. Other effects are the same as in the first to fifth embodiments.

5 and 6 are a cross-sectional view of a fifth embodiment of the device of the present invention and a plan view of the motor. This structure is a diagram showing an example of a structure in which the motor rotor is built into the drum, and the motor stator is provided in a recess provided outside of the lower drum 5.

Stator coil 21 and position sensor 40 of the motor stator
etc. are inserted into a through hole 650 provided on the bottom surface of the drum 5, facing the magnetic pole surface of the upper rotor magnet 18, so that they can be linked to and detected by the magnetic flux. central axis 1
A yoke 65 and an FG magnet 70 are fixed to the lower end so that an FG flaw signal can be generated on the FG pattern conductor provided on the substrate 250 surface on the lower surface of the motor stator yoke 22 during rotation. The board 25 is a motor wiring board,
Reference numeral 25' designates a board for unwired coil ends of the rotary transformer 14, terminal wiring of signal processing circuits such as the fixed side signal amplifier 107, and FG signal generation. A rotary transformer 14 , 15 is provided within the inner diameter of the rotor magnet 18 . Other structures and functions are the same as those of the first to fourth embodiments. According to the structure of this embodiment, the motor rotor magnet 18 is connected to the drum 5.
Since it is built inside the motor, the number of steps required to assemble the motor can be reduced.

Furthermore, since the stator is assembled externally, operations such as adjustment, inspection, and replacement of various parts within the stator can be easily performed.

Further, parts for fixing the motor rotor to the shaft 1 can be eliminated. Further, a rotating body fixed at the upper and lower ends of the shaft 1 (the upper end is the upper drum 2, the head 100, the disk structure 75)
1 rotation transformer 15. The rotating part consisting of the slip ring structure 210, etc., and the rotary yoke 22 at the lower end have a structure with large and small moments of inertia (the upper end is a dog, the lower end is small), so the torsion of the shaft 1 is unique. The vibration frequency can be increased, the resonance resistance against external vibrations can be improved, and low rotational unevenness and low jitter characteristics can be achieved.

FIG. 7 is a sectional view of a sixth embodiment of the device of the present invention, which is a structural example using a fluid bearing that utilizes the dynamic pressure of fluid as the bearing.
(α) is a cross-sectional view of the overall configuration, and (b) is a cross-sectional structural view of a housing sleeve structure 800 for a fluid dynamic pressure bearing that engages with the central rotating shaft. In the figure, 801 is a group (narrow groove part);
805 is a thrust support piece, and 802 is a height adjustment screw. The mounting structure of the motor section is similar to that of the fifth embodiment. According to the structure of this embodiment, since a fluid dynamic pressure bearing is used, the vibration of the running tape and the vibration of the head 100 are reduced during rotation, and the contact characteristics between the tape 400 and the head 100 are improved, resulting in low jitter and low S/N. The following characteristics are obtained.

Further, the bearing dimensions can be reduced, the diameter of the rotary transformers i4 and i15 can be reduced, and the motor space can be increased.

By reducing the diameter of the rotary transformers 14 and 15, the signal transmission band can be widened with low loss, and by increasing the size of the motor, it is possible to improve efficiency and reduce rotational unevenness. Furthermore, since a height adjustment screw piece 802 is provided at the bottom of the thrust support piece 805, the upper drum 3 and the head 1
Adjustment of the height position such as 00 can be easily performed.

FIG. 8 is a cross-sectional view of a seventh embodiment of the device of the present invention, with the central axis 1
is fixed to the center of the bottom surface of the lower drum 5 by press-fitting or the like, and a thrust support piece 805 is provided on the upper drum 2 to support the thrust load on the upper end surface of the shaft 1. The structure of the recess 600 in the lower part of the lower drum 5 and the structure of the driving motor are the same as in the fifth and sixth embodiments. The structure of this embodiment also has substantially the same effects as those of the fifth and sixth embodiments.

In the above embodiment, the motor parts or the FG parts are housed in the recess 600 below the bottom of the lower drum 3, but the structure may be such that components of the rotary transformer, the drive circuit, etc. are housed therein.

〔Effect of the invention〕

According to the present invention, (11) the drive motor etc. are housed in the recess below the bottom of the lower guide drum, so the dimensions and structure of the device can be made thin, lightweight, and compact. Since the assembly work can be done while always keeping the device in an upright position, the work is easy and there is less risk of damaging components such as the drum surface and motor parts 9 heads.In addition, the assembly work can be easily automated and is suitable for mass production.

(2) Since the axial length of the central shaft can be shortened, torsional vibration of the shaft can be reduced. This makes it possible to suppress uneven rotation of the head rotating body and achieve low jitter.

(3) The transformer can be made smaller because it can easily incorporate a cylindrical rotary transformer in a thin structure.

It is possible to easily achieve low crosstalk of transmission signals, equalization of transmission characteristics between channels, multi-channelization, etc.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the first embodiment of the device of the present invention, Fig. 2 is a schematic diagram of the same embodiment, Fig. 5 is a sectional view of the second and fifth embodiments, and Fig. 4 is the fourth embodiment. 5 and 6 are cross-sectional views of the fifth embodiment, FIG. 7 is a cross-sectional view of the sixth embodiment, and FIG. 8 is a cross-sectional view of the seventh embodiment. 1・・・・・・・・・・・・・・・Central axis 6・・・・・・
...Lower guide drum 18...
......Rotor magnet 21...
...Stator coil 600...
・Concavity 14.15・・・Rotating transformer agent Patent attorney Katsuo Ogawa

Claims (1)

[Scope of Claims] 1. A rotating body having a recording or reproducing head fixed to its outer periphery, a central shaft arranged concentrically at the center of rotation of the rotating body and supporting the rotating body, and the rotating body and a guide drum provided concentrically with the central axis and having a guide portion for running a recording medium on the outer circumferential surface; a drive motor concentrically and directly connected to the rotating body or the central axis; and the rotating body and the central axis. A rotary head device comprising a rotary transformer for transmitting recording or reproduction signals provided concentrically with the guide drum, characterized in that a concave portion is provided concentrically with the central axis on the back surface of the bottom surface of the guide drum. . 2. The rotating head device according to claim 1, further comprising: a central rotating shaft fixed to the first rotating body including the head and passing through the bottom surface of the guide drum via a bearing; A rotary head device characterized by a configuration in which a second rotating body is disposed within a recessed portion of the rotary head device. 3. The rotary head device according to claim 2, wherein the second rotating body is a rotor of a drive motor. 4. The rotary head device according to claim 2 or 3, wherein the mounting height position of the drive motor in the axial direction is located at a position higher than the position of the recording medium guide portion of the guide drum. 5. The rotary head device according to claim 1, claim 2, claim 3, or claim 4, wherein a cylindrical rotary transformer is used as the rotary transformer. 6. In the rotary head device according to claim 2, claim 3, or claim 4, the stator of the drive motor is disposed below the rotor, and the inner circumference or outer circumference of the stator is aligned with the guide drum surface. A rotary head device characterized by having a structure that is fixed directly or indirectly to.