JPH0366052A - Rotating head type magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To correctly detect the rotary phase of a head by directly providing a magnet for face detection on the rotating drum fitted with the head and detecting the rotating position of this magnet by a magnetic core for phase detection provided on a fixed drum. CONSTITUTION:When a rotating drum 9 is rotated, a magnet 15a for phase detection is passed through on the magnetic core 19 for phase detection of a fixed drum 10. At this time the flow of a magnetic flux is caused among the magnet 15a, core 19, stator side core 16 and rotor side core 12 and the voltage VA equivalent to this magnetic flux variation is induced on a stator side coil 18a. Also in the case of the magnet 156 for phase detection passing through on the core 19, the voltage VA and voltage VB of reverse phase are induced on the coil 18a. The fitting positions of the magnets 15a and 156 and core 19 can be positioned with high accuracy in advance. The rotating phase of the head fitted to the drum correctly is detected as well by directly detecting the rotating phase of the rotary drum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention records data on a magnetic tape by scanning tracks extending in the width direction of a running magnetic tape with a head attached to a rotating drum. The present invention relates to a rotary head type magnetic recording and reproducing device that reproduces data from a rotary head.

In a conventional rotary head type magnetic recording/reproducing apparatus, it is necessary to accurately detect the period during which the head is in contact with the magnetic tape, and to record data on the magnetic tape within that period.

Apart from this, in order to ensure compatibility between magnetic recording and reproducing devices, there is a need to limit the scanning section of the head relative to the magnetic tape track to a certain range, and from this point of view as well, the rotational phase of the head It is necessary to detect accurately.

In order to meet these demands, in a conventional rotary head type magnetic recording/reproducing device, a magnet 2 is attached to the outer periphery of the rotor 1 of the drum motor, as shown in a perspective view and a plan view in FIGS. 5 and 6, respectively. is installed, and a Hall element 5 is placed on a printed wiring board 4 provided on a part of the stator 3 of the same drum motor, and the Hall element 5 detects the position of the rotating magnet 2, thereby causing it to rotate together with the rotor 1. The rotational phase of the head 7 attached to the upper drum 6 is detected.

Problems to be Solved by the Invention However, in the above-described conventional rotary head type magnetic recording and reproducing device, the magnet 2 is attached to the rotor 1 of the drum motor, which is connected to the upper drum 6 via a main shaft (not shown). Since the Hall element 5 that detects the magnet 2 is arranged on the printed wiring board 4 provided on a part of the stator 3 of the drum motor, mechanical attachment of the magnet 2 and the Hall element 5 to the upper drum 116 is easy. The error increases due to the intervening members, and the above mounting causes an error corresponding to the error in the output pulse from the head position detection circuit that determines the rotational phase of the head 7 based on the detection of the magnet 2 by the Hall element 5. Become.

That is, in the conventional example described above, instead of directly detecting the rotational phase of the head 7 attached to the upper drum 6, by detecting the rotational phase of the rotor 1 of the drum motor connected to the upper drum 6, Since the rotational phase of the head 7 is indirectly detected, the detection error increases accordingly.

Furthermore, since the position of the magnet 2 is detected using the Hall element 5, the pulse width of the detection pulse becomes wide, and from this point of view as well, it is difficult to accurately detect the rotational phase of the head 7. .

Therefore, in order to reduce the above-mentioned errors, in conventional rotary head type magnetic recording and reproducing devices, an adjustment circuit is added to the head position detection circuit to electrically correct the above-mentioned errors, and a separately prepared reference reproduction It was necessary to use a tape, determine the above-mentioned error from the reproduced data, and adjust the output timing of the detection pulse output from the head position detection circuit by the amount of the error.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotary head type magnetic recording/reproducing apparatus that can accurately detect the rotational phase of a head without requiring an am circuit for correcting the output timing of detection pulses.

Means for Solving the Problems The present invention comprises a rotating cylinder including a rotating drum to which a head is attached and a stationary drum arranged coaxially with respect to the rotating drum, the head of the rotating cylinder traveling In a rotating head type magnetic recording/reproducing device that records data on a magnetic tape by scanning tracks extending in the width direction of the magnetic tape, or reproduces data from a magnetic tape, a A phase detection magnet is provided on a part of the magnetic core on the rotating drum side that is electrically connected to the head, and a magnetic core on the fixed drum side that is provided on the fixed drum side and electromagnetically coupled to the magnetic core on the rotating drum side. A phase detection magnetic core facing the rotation path of the phase detection magnet is provided in a part of the magnetic core, and a change in magnetic flux generated in the phase detection magnetic core as the rotating drum rotates is transferred to a winding wound around the fixed drum side magnetic core. This is a rotary head type magnetic recording/reproducing device characterized in that the rotational phase of the head is detected based on the detected signal.

According to the present invention, the rotational position of the phase detection magnet provided directly on the rotating drum is detected as a magnetic flux change in the phase detection magnetic core provided on the fixed drum side, so that the rotational phase of the rotating drum is detected. The rotational phase of the head attached to the rotating drum will therefore be detected accurately.

Embodiment FIG. 1 is a vertical cross-sectional view showing a partial configuration of a rotating cylinder 8 in a rotating head type magnetic recording/reproducing apparatus which is an embodiment of the present invention, and FIG. 9, and FIG. 3 shows a plan view of the lower drum 1° of the rotary cylinder 8. The zero-rotation cylinder 8 is directly connected to a drum motor (not shown) and rotates three times. It is composed of an upper drum 9 as a rotating drum, and a lower drum 10 as a fixed drum disposed directly below the upper drum 9 coaxially and facing the upper drum 9.

Two heads lla and llb for scanning the magnetic tape are attached to the outer periphery of the upper drum A 9 at an angle of 180° in the circumferential direction. Further, inside the upper drum 9, a ring-shaped rotor-side magnetic core 12 as shown in FIG. It is formed. These windings 13a and 13b each have a rotor winding 14a.

14b is installed, and one volume 11114a is head 1
1a, and the other volume 1114b is the other head 11b.
are electrically connected to each other. Furthermore, two phase detection magnets 15a and 15b, which correspond one-to-one to the heads 11a and llb, respectively, are attached to the outer periphery of the rotor-side magnetic core 12 at an angle of 180'' in the circumferential direction. .

The two phase detection magnets 15a and 15b described above have a generally inverted shape, for example, as shown in FIG. 1, and their polarities are connected to each other in reverse.

That is, for example, one phase detection magnet 15a is arranged so that its downwardly extending end is N%, while the other phase detecting magnet 15b has an S pole at its downwardly extending end. It is arranged like this.

On the other hand, a ring-shaped stator-side magnetic core 16 shown in FIG. 3 is provided in the lower drum 10 so as to coaxially oppose the rotor-side magnetic core 12 of the upper drum 9. and the rotor-side magnetic core 12 are electromagnetically coupled. The stator side magnetic core 16 also has two winding grooves 17a, 17 opposite to the winding grooves 13a, 13b.
b are formed coaxially and these windings? 1t17a, 17
Stator windings 18a and 18b are attached to each of the stator windings 18a and 18b, respectively. Further, a phase detection magnetic core 19 is provided on the outer peripheral portion of the stator side magnetic core 16 so as to face the rotation path of the phase detection magnets 15a, 15b.

FIG. 4 shows the above-mentioned rotating drum 8 and this rotating drum 8.
FIG. 2 is a circuit diagram showing an 11F connection configuration with a circuit that processes an output signal from the circuit. A terminal of the stator side winding 11118a is connected to the head amplifier 20a, and a terminal of the other stator side winding 18b is connected to another head amplifier 20b. Furthermore, a phase detection low-pass filter 21 and a reproduced signal extraction bypass filter 22a are connected to the output terminal of the head amplifier 20a, and the other head amplifier 2
Another reproduced signal extraction bypass filter 22b is connected to the output terminal 0b.

Next, we will explain the rotational phase detection operation of the rotary head type magnetic recording and reproducing device.Each time the 0-rotation drum 9 makes one rotation, the phase detection magnets 15a and 15b are activated only once each on the fixed drum 10111. It passes over the core 19. For example, when the phase detection magnet 15a passes, there is a gap between the phase detection magnet 15a, the phase detection magnetic core 19, the rotor-side magnetic core 16, and the stator-side magnetic core 12, as indicated by arrow A in FIG. A flow of magnetic flux occurs,
The voltage ■6 corresponding to this magnetic flux change is the stator side winding 18
It is induced by a.

A flow of magnetic flux also occurs when the other phase detection magnet 15b passes over the phase detection magnetic core 19, but the polarity of the phase detection magnet 15b is set opposite to that of the phase detection magnet 15a. Therefore, the flow of magnetic flux is in the opposite direction to the arrow A, and the voltage V induced in the stator side winding 1818a at this time has the opposite phase to the voltage vA. By detecting these voltages VA and Va, two phase detection magnets 15a and 1
5b is detected.

Due to the electromagnetic coupling between the rotor-side magnetic core 12 and the stator-side magnetic core 16, the stator-side winding 18a has a head ll.
A reproduction signal V read from the magnetic tape by a is also extracted. Since the frequencies of the voltages V A and V m are sufficiently small compared to the frequency of the reproduced signal, the head amplifier 20
After being amplified by step a, it is separated from the reproduced signal by a low-pass filter 21 and taken out. On the other hand, the reproduction signal V corresponding to the head lla.

is separated by the voltage VAV and taken out by the bypass filter 22a. Furthermore, the reproduction signal vt read from the magnetic tape by the other head llb is led to the stator f11 winding atab, further amplified by the head amplifier 20b, and then taken out via the bypass filter 22b.

In this embodiment, since the mounting positions of the phase detection magnets 15a, 15b corresponding to the heads lla, llb can be set in advance on the lower surface side of the upper drum 9, these phase detection magnets 15a.

15b can be positioned with high precision.

In addition, the mounting position of the magnetic core 19 for phase detection is also different from that of the lower drum 1.
Since it can be set in advance on 0, the positioning can be performed with high precision.

Effects of the Invention As described above, according to the rotating head type magnetic recording/reproducing device of the present invention, a phase detection magnet is directly provided on the rotating drum to which the head is attached, and the rotational phase of this magnet is provided on the fixed drum side. Since the rotational phase of the head is detected by detecting the change in magnetic flux in the magnetic core for phase detection, there is no installation error.
The installation eliminates the need for an adjustment circuit or adjustment process to correct detection errors in the rotational phase of the head due to errors, making it possible to accurately detect the rotational phase of the head.

[Brief explanation of drawings]

FIG. 1 is a longitudinal section showing a partial configuration of a rotating cylinder in a rotating head type magnetic recording/reproducing device which is an embodiment of the present invention, FIG. 2 is a bottom view showing an upper drum of the rotating cylinder, and FIG. The figure is a plan view showing the lower drum of the rotating cylinder, Figure 4 is a circuit diagram showing the connection configuration between the rotating cylinder and the circuit that processes its output signal, and Figure 5 is a conventional rotating head type magnetic recording/reproducing system. FIG. 6 is a perspective view showing the configuration of a rotating cylinder in the apparatus, and FIG. 6 is a bottom view of the rotating cylinder.

Claims (1)

[Scope of Claims] A rotating cylinder including a rotating drum to which a head is attached and a stationary drum disposed coaxially with respect to the rotating drum, the head of the rotating cylinder is configured to rotate the magnetic tape in the width direction of the running magnetic tape. In a rotary head type magnetic recording/reproducing device that records data on a magnetic tape or reproduces data from a magnetic tape by scanning a track extending over the entire length of the magnetic tape, electricity is connected to the head via a winding provided on the rotating drum side. A phase detecting magnet is provided on a part of the rotating drum side magnetic core which is connected to the rotating drum side, and a phase detecting magnet is provided on a part of the fixed drum side magnetic core which is provided on the fixed drum side and is electromagnetically coupled to the rotating drum side magnetic core. A magnetic core for phase detection is provided facing the rotation path of the detection magnet, and changes in magnetic flux generated in the magnetic core for phase detection as the rotating drum rotates are detected by a winding wound around the magnetic core on the fixed drum side. A rotary head type magnetic recording/reproducing device characterized in that the rotational phase of the head is detected based on this detection signal.