JPS6218652A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the rotation precision and to make a product low-cost by providing a magnetized part, where N and S poles are formed alternately, in the peripheral end part of the rotor of a rotary transformer and forming magnetic poles for rotation position generator of about a half size of said poles in optional magnetic poles of the magnetized part and arranging a magnetic detecting means at the vicinity of a magnetized part. CONSTITUTION:Channel coils 41 and 42 are assembled in a rotor 40 in concentric rings, and a magnetized part 45 where N poles 43.43... and S poles 44.44... are formed alternately is provided in the peripheral end part. Magnetic poles 46 and 47 for rotation position generator of about a half size of poles 43 and 44 are formed in optional N pole 43 and S pole 44 forming the magnetized parr 45, and a rotor 40 is formed with a magnetic material in the magnetized part 45, and the rotor 40 is combined with a stator 48 corresponding to the rotor 40 to constitute a rotary transformer 49. If frequency generators and rotation position generators are used while utilizing the rotary transformer they are equipped easily because the rotary transformer requires high-precision attachment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a signal for controlling a rotating drum of a magnetic recording/reproducing device.

[Background of the invention]

Generally, in magnetic recording and reproducing devices such as video tape recorders, a rotary transformer installed inside the rotating head cylinder is used to transmit signals between a magnetic head attached to a rotating head cylinder and a recording/reproducing amplifier.
Rotation control of the rotary head cylinder is performed by a motor installed inside the rotary head cylinder, and the control is actually performed by an encoder having a frequency generator and a rotational position generator installed in the motor. This is done by output signal. The frequency generator output and rotational position generator output signals for rotation control can be obtained from either of the rotary head cylinders, but at present, motor noise may be superimposed on the video signal line, and it is difficult to use a single motor. The output is obtained from the motor as necessary for performance evaluation, and its structure is as shown in FIGS. 5 to 7. That is, in FIG. 5, 1 is a rotary head cylinder, and this rotary head cylinder 1 is used for video heads 2 and 2 for each channel.
Upper rotating drum 3 and lower fixed drum 4 with attached
A drum motor 5 is provided below the lower fixed drum 4, and a drive shaft 6 of the drum motor 5 passes through to the upper rotating drum 3. An encoder 7 having a frequency generator and a rotational position generator is mounted on the lower surface of the drum motor 5, and the output from the encoder 7 is obtained from terminals 8.

Furthermore, in the figure, 10 is a rotary transformer installed in the upper rotating drum 3, and this rotary transformer 10 is composed of a rotor 11 and a stator 12.

Moreover, FIGS. 6A to 6D show specific structural examples of the encoder 7 in the rotary head cylinder 1 shown in FIG. 5, and FIG. 6A shows an optical type encoder.

In this figure 6A, 13 in the figure is a rotating disk,
A plurality of slits 14, 14, . . . are formed at regular intervals on the circumferential edge of the rotating disk 13. Further, the peripheral edge of the rotating disk 13 on which the slits 14@14... are formed passes between a light emitting element 15 such as an LED and a light receiving element 16 such as a phototransistor, and the slits 14, 14... When light passes through, a signal is obtained, and the number of these three 2 T 14, 14... determines the frequency.

Further, FIG. 6B shows a mechanical type, in which numeral 17 is a rotating disk in which gear-shaped grooves 18 that are alternately uneven are formed on the peripheral end surface, and numeral 19 is the groove 18 of the rotating disk 17. This is a head sensor arranged in accordance with the

In the case of the mechanical encoder shown in FIG. 6B, outputs are obtained from the head sensor 19 corresponding to the number of grooves 18 of the rotary disk 17.

Furthermore, Fig. 6C shows a magnetic type, and in the figure 20
is a magnetic rotating disk of a rotor in a motor, and N poles 21, 21,
... and S poles 22, 22, ... are formed alternately, and 23 is a magnetic sensor arranged corresponding to each of the magnetic poles 21, 22. In the case of the magnetic encoder shown in FIG. 6C, a generator signal is obtained by a magnetic sensor 23.

Moreover, what is shown in FIG. 6D is a rotary position generator for position detection.
rL machine, and this rotational position power generation @24 has a rotating disk 25 with an N-pole magnet pin 26 at a diametrically symmetrical position on the peripheral end surface.
and a south pole magnet pin 27, each of which is provided with a rotating disk 25, each of which is provided with a magnetic pin 26, 27.
A magnetic detection sensor 28 is arranged corresponding to the circumferential end surface of. In the rotational position generator 24 shown in FIG. 6D, the positions of the magnet pins 26 and 27 are obtained as the output of the magnetic detection sensor 28, and this output is used for controlling the rotational phase of the rotary head cylinder 1. It is something.

On the other hand, FIG. 7 is an exploded perspective view of the rotary transformer 10 installed in the upper rotating drum 3 of the rotating head cylinder 1. The rotor 11 and stator 12 have A channel coils 29a, 29b and B channel coil 3, respectively.
0a and 30b are assembled in a concentric ring shape.

The conventional rotary cylinder 1 is constructed as described above, and each channel coil 29b of the stator 12 of the rotary transformer 10 is connected during recording.

30b receives a modulated RF multiplied signal such as a video or audio signal, which is converted into magnetic flux and transmitted to the rotor 11 side, and the transmitted signal is connected to the video head 2. 2.2 is recorded on a magnetic tape that is scanned by contact. During playback, signals are obtained through the reverse path to the recording path described above.

However, in this conventional magnetic recording/reproducing device, the number of parts of the encoder 7 attached to the drum motor 5 increases, which contributes to a rise in price, and requires a high level of adjustment accuracy. In addition, the drum motor 5 consumes a considerable amount of power in order to generate rotational torque, and as a result, the noise power that goes out is large, and the encoder 7 itself also generates a considerable amount of noise. 2, it has become a travesty to take the output of a frequency generator or a rotary position generator from the drum motor 5 located below the lower fixed drum 4.

[Purpose of the invention]

The present invention has been made by focusing on the problems of the prior art described above, and eliminates the problems, eliminates the need for highly accurate adjustment of the motor, simplifies the structure, and reduces the high power noise generated by the motor. It is an object of the present invention to provide a magnetic recording/reproducing device which can reduce the influence, improve rotation accuracy, and reduce the cost of the product.

[Summary of the invention]

In order to achieve this object, the present invention provides a magnetized portion in which N poles and S poles are alternately formed at the peripheral end of the rotor of a rotary transformer made of a magnetic material attached to a one-turn head cylinder, and , within the magnetic pole of the magnetized part, about 2
A magnetic pole for a rotational position generator of about 1/2 of that is formed, and a magnetic detection means is arranged near the #J magnetized demagnetization part, so that the rotary transformer has an encoder function having a frequency generator and a rotational position generator. It is a characteristic that it possesses.

This configuration eliminates the need for highly accurate adjustment of the motor, simplifies the structure, and obtains control signals from the transformer directly connected to the video head, improving rotational control accuracy and reducing product prices. You can also do it.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

FIG. 1 is a perspective view of a rotor 40 of a rotary transformer molded from a magnetic material according to the present invention, seen from the bottom, and the rotor 40 has channel coils 41 and 42 arranged in concentric rings as in the prior art. It is assembled, and the peripheral edge has N poles 43, 43... and S poles 44-44...
Magnetized portions 45 are provided which are formed alternately. Furthermore, each of the arbitrary N poles 43 and S poles 44 forming this celadon part 45 is further provided with a rotational position generator magnetic pole 46 of about one half of the N pole 43 and S pole 44 .
47 is formed, and since the rotor 40 is molded from a magnetic material, this magnetized portion 45 can be easily magnetized.

Further, as shown in FIG. 2, this rotor 40 is combined with a corresponding stator 48 to form a rotary transformer 49.

An integral circuit board 50 facing the celadon part 45 of the rotor 40 is formed at the outer peripheral end of the stator 48 constituting the rotary transformer 49. The signal is extracted as a signal, and its specific configuration is shown in FIG. In this integral circuit board 50, the frequency generator output is obtained from terminals 51, 51, and the terminals 51, 51 are formed by an annular uneven pattern 52 with a part cut away.
By forming this uneven pattern 52, the N pole 43. of the magnetized portion 45 of the rotor 40 is connected to Magnetization unevenness and the like are integrated according to the number of magnetizations of the S poles 44 and the number of teeth of the concavo-convex pattern 52, and a stable frequency generator output can be obtained. Further, numeral 53 in the figure is a rotational position detection pattern, and the rotational position generator output from this rotational position detection pattern 53 is obtained from terminals 54-54. The interval between the rotational position detection patterns 53 is half the interval between the concavo-convex patterns 52 for the output of the frequency generator, and the signals from the rotational position generator magnetic poles 46 and 47 are not mixed. If so, it can be obtained as a signal for each cycle.

In this embodiment, the output as a rotary position generator is obtained every cycle, but it is also possible to obtain an output every half cycle by forming the magnetic poles for the rotary position generator. Department.

The magnetic recording and reproducing apparatus according to the present invention is configured as described above, and if a frequency generator and a rotational position generator are used by using a rotary transformer, the magnetic recording and reproducing apparatus according to the present invention can be used.

Since rotary transformers require high-precision installation, they can be easily installed.

〔Effect of the invention〕

As described above, according to the present invention, there is no need for highly accurate adjustment of the drum motor, and since the molding material of the original rotary transformer can be used, it can be easily manufactured and the overall structure can be simplified. In addition, the influence of high-power noise generated by the drum motor is reduced, and the presence of a frequency generator and a rotational position generator in the upper rotating drum of the rotating head cylinder to which the video head is attached improves rotational control accuracy. and the product price can be lowered.

[Brief explanation of the drawing]

1 is a perspective view of a rotary transformer seen from below, showing an example of the implementation of the present invention; FIG. 2 is a vertical sectional view of the rotary transformer; FIG. 3 is a plan view of the integral circuit board; The figure is an enlarged plan view of the magnetized part, FIG. 5 is a perspective view of a rotary head cylinder showing a conventional example, and FIGS. 6A to 6
Figure C is a partial perspective view showing the configuration of the same encoder.
Figure D is a perspective view schematically showing the rotary position generator of the encoder, and Figure 7 is an exploded perspective view of the rotary transformer. l... Radoshirin to rotation! -40...Rotor 43
...N pole 44...S pole 45...Magnetized part 46.
47... Magnetic pole for rotational position generator 49... Rotary transformer 50... Integral circuit board 52... Uneven pattern 53
...Rotational position detection pattern Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 6A Fig. 68 Between whistles Fig. 6C Fig. 6D

Claims (1)

[Claims] A magnetized part with alternating N and S poles is provided at the peripheral end of the rotor of a rotary transformer attached to a rotating head cylinder, and within or near the magnetic pole of the magnetized part,
Magnetic poles for a rotational position generator are formed at each end every period or every 1/2 period, and a magnetic detection means is disposed close to the magnetized portion, so that the rotary transformer is connected to a frequency generator and a rotational position generator. 1. A magnetic recording and reproducing device characterized in that it has an encoder function.