JPS5883358A - Rotary magnetic head drum - Google Patents

Abstract

PURPOSE:To prevent deterioration, in the S/N ratio of a rotation signal, and to facilitate assembling and adjusting work, by sticking in one body a multipolar magnet consitituting the frequency generator of a rotary magnetic head drum and magnets for rotary phase detection. CONSTITUTION:Magnets 23a and 23b for rotary phase detection are embedded at both ends of a multipolar magnet 12 on its diameter, and outer circumferential sirfaces of the both are nearly in the same plane. A magnetic detector 24 is suspended on bottom surface of a printed wiring board 5 while facing the magnets 23a and 23b. Since a rotor magnet 9 and a stator coil 11 form a motor part, the whole device rotates in one body when a current flows through the coil 11. This constitution eliminates magnetic leakage from the magnet 9, so the magnetic detector 24 generates rotary phase detecting signals of magnetic heads 2a and 2b having less deterioration in S/N ratio. Further, assemble and adjusting work are facilitated because there is no projection on the outer circumferential surface of a magnet yoke.

Description

[Detailed Description of the Invention] The present invention! This article relates to the structure of a whirling rotating magnetic head drum, and relates to a rotating magnetic head drum that prevents the deterioration of the 81N ratio of the jFiK rotation detection signal. Figure 1 shows an example of a conventional rotating magnetic head drum. Figure 2 is a bottom view of the main part, Figure 3 is a partial cutaway diagram.
FIG. 2 is a schematic plan view of a multipolar magnet shown in FIG.

In the figure, 1 is a rotating drum, 2a and 2b are magnetic heads mounted on the lower periphery of the rotating drum 1, and 6 is a rotating shaft fixed to the center of the rotating drum 1 and rotating integrally therewith. , 4 is a fixed drum whose center portion is penetrated by the rotating shaft 6.

3 is a bearing of the rotary shaft 6 mounted on the fixed drum 4; 5 is a grid/grid wiring board with printed wiring 21 provided on its underside (see FIG. 2); 8 is a cylindrical rotor magnet having a bottom) Reference numeral 7 denotes a bearing support, a portion of which is fixed to the bottom of the rotating shaft 6 and the rotor magnet yoke 8, respectively.

9 is a rotor magnet fixed to a part of the inner surface of the side surface of the rotor magnet yoke 8, 10 is a stay core provided at a position facing the rotor magnet 9 and fixed to the lower part of the fixed drum 40, and 11 is the core. The stator coil is wound around the stator coil.

Reference numeral 12 indicates the rotor magnets (multi-polar magnets) provided at the upper end of the cylindrical portion of the yoke 80 and arranged alternately so that the magnetic poles are in opposite directions (see Figure 113). ) 12 to form a frequency generator (hereinafter referred to as FG).

Reference numerals 13m and 13b designate rotational phase detection magnets that are provided at diametrically opposed positions on the side surfaces of the rotor magnet yoke 8, and a portion of which is fixed by being driven into a round hole.

The magnets 13m and 13b are formed so as to pass through IIIWIi of the rotor magnet edge 8 so that one end is in contact with the rotor magnet 90 side WK, and the other end is protruded from the center from the surface.

A magnetic detector 14 is suspended from the printed wiring board 5 and provided at a position facing the magnets 13a) and 13b.

The magnets 13a * 13b and magnetic detection 1111
4 forms a rotational phase detector.

The rotor magnet 9 and stator coil 11 form a motor section. Therefore, when a current is applied to the coil 11, the rotor magnet 9, the rotor magnet 8, the multipolar magnet 12, and the magnet) 13m
, 13b rotate integrally.

At the same time, the rotating shaft 6, which is connected to the rotor magnet yoke 8 by a bearing support 7, also rotates integrally with the rotating drum 12 and the magnetic heads 2m, 2b.

By performing an operation like mie, the magnetic detector 1
4, the magnetic head 2m, 2bO11 phase shift detection signal can be obtained. However, in the above-mentioned device, the above-mentioned 9 and s'! > A hole is provided on the side surface of the rotor magnet holder 8, and a rotational phase detection magnet is inserted through the hole.
3a and 13b are provided.

For this reason, magnetic leakage of the rotor magnet 9 of the motor section occurs through the hole, which frequently causes a disadvantage that the 8/N ratio of the output signal from the magnetic detector 14 deteriorates.

Furthermore, since there is a risk of bringing about the drawbacks mentioned above,
Magnetsu) 13a * The drawback was that it was not possible to increase the size of IAB.

Also, since a part of the magnets 13m and 11b protrudes from the side of the W-ring 8, it is easy for that part to be damaged during assembly and adjustment work.
The disadvantage was that the work was difficult.

The object of the present invention is to provide a rotating magnetic head drum that eliminates the above-mentioned drawbacks, prevents deterioration of the rotation detection signal ratio, and makes assembly and adjustment work easier.
Ru.

In order to achieve the above-mentioned object, the present invention fixes and integrates a multipolar magnet constituting a PG of a rotating magnetic heliad drum and a magnet for detecting a rotational phase.

Embodiments of the present invention will be described below with reference to the accompanying drawings. 4m is a partial cross-sectional view of the first embodiment of the present invention, and FIG. 5 is a plan view of the main part thereof. In FIG. Place the multi-pole magnets at both ends of the Owe so that the number of magnets becomes 1,000 yen (see Figure 5).
is suspended from the bottom surface of the printed wiring board 5, and the magnets)
This is a magnetic skewer installed at a position facing 23m and 23b.

When a current is applied to the stator coil 11 in the rotation detector 2 having the above-described configuration, the rotor magnet 9, the rotor magnet 8, the multipolar magnet 12, and the magnets 23m and 23b rotate integrally.

(9) At the same time, the rotating shaft 6 connected to the rotor magnet roller 8 by the bearing support 7 also rotates integrally with the rotating drum 1 & magnetic heads 2a, 2b.

At this time, the magnetic detector 24 obtains rotational phase detection signals of the magnetic heads 2m and 2j with little deterioration in the S/N ratio.

FIG. 6 is a partial sectional view of a second embodiment of the invention. In the figure, the same reference numerals as in FIG. 1 indicate equivalent parts with the same round lines.

Reference numeral 15 denotes a printed wiring board 25, which is provided facing multipolar magnets 22 in which the directions of lines of magnetic force are alternately arranged in opposite directions; This is a magnetic shielding case coupled to a plate 15.

16 a wiring board; 17 a stator board fixed to the lower surface of the wiring board 16; 18 a stator board 1712;
) Bottom 11! A part of the stator coil 20 installed in the bearing support A7 is fixed to the lower end of the bearing support A7. A magnet net 19 is a rotor tag net placed on the rotor magnet yoke 20, facing the stator coil 18.

33m and 33b are embedded in both ends of one diameter of the multipolar magnet 22 so that the outer surface thereof is approximately on the same plane as the outer surface of the multipolar magnet 22.
This is a phase detection magnet.

Further, 34 is a magnetic detector supported by the printed wiring board 15 and provided at a position facing the magnets 33m and 33b.

When a current is applied to the stator coil 18 in the Oa-transfer detector having the above-described configuration, the rotor magnet 19, the rotor magnet yoke 20, the multipolar magnet 22, and the magnets 33a and 33b rotate integrally.

At the same time, the bearing support 7
The rotating shaft 6 connected to the lever 20 also rotates together with the rotating drum 1 and the magnetic heads 2a, 2b.

At this time, the magnetic head 2*, 2bO@ phase shift detection signal with little deterioration of the d, 87N ratio is obtained from the magnetic detector 34.

In this example, the rotation detector magnet) is 33 m.

33b, including the motor part, is covered by a magnetic shielding case 25.
, 33b is no longer likely to affect the outside as noise.

FIG. 7 is a partial sectional view of a third embodiment of the present invention. In the figure, the same reference numerals as in FIG. 1 represent the same or equivalent parts.

36 has an upper end portion attached to the lower end portion of the magnetic shielding case 45 fixed to the lower surface of the fixed drum 4.
27 is a wiring board fixed in parallel with the wiring board 36.
The nine stator quills 28 are provided on the top surface of the stator blind 27, and the remaining nine stator quills 28 are provided on the top surface of the stator blind 27.

29 is a rotor magnet fixed to the bearing support A7.
The rotor tag net 32, which is fixed to the rotor magnet 300 and is provided at a position facing the coil 28, is placed on the rotor magnet N-ri 30 so that the directions of the magnetic lines of force are opposite to each other. The alternately arranged multipolar magnets 043m and 43b are embedded in both ends of one diameter of the multipolar magnet 32 so that their outer surfaces are approximately on the same plane as the outer surface of the multipolar magnet 320. For embedded rotation detection! 44 is a printed wiring board that is located inside the magnetic shielding case 45 and is fixed to the lower part of the fixed driver 54. 44 is a printed wiring board that is fixed to the printed wiring I [35 and the magnet) 43a: This is a magnetic detector placed at a position facing $p and 43b.

When a current is applied to the stator coil 28 using the rotation detector configured as described above, the four-tapered magnet 29,
-Tag net yoke 30. The multipolar magnet 32 and the magnets 43a and 43b rotate together.

At the same time, the rotating shaft 6 connected to the rotor magnet yoke 30 by the bearing support 7 also rotates together with the rotating drum 1 & magnetic heads 2m, 2b.

At this time, the magnetic detector 44 obtains rotational phase detection signals of the magnetic heads 2m and 2b with little deterioration in the S/N ratio.

In this example, for rotational phase detection! Gunnet) 43m.

43b, including the motor part, is covered by the magnetic shielding case 45, so that the magnets 43m and 7 by 43b are covered in the same way as described above in FIG.
There is no possibility that magnetic leakage will affect the outside as noise. :' In the above description, the magnet for detecting the rotational phase is provided so as to be inserted into the multipolar magnet, but it goes without saying that it may also be provided by adhesive bonding or press-fitting.

As described above, in the present invention, the FG multipolar magnet of the rotating magnetic head drum and the rotational phase detection magnet are fixedly integrated, so that the deterioration of the 87N ratio of the rotation detection signal can be prevented, and the assembly work and adjustment can be reduced. It has the advantage of making the work easier.

Brief explanation of t sin Fig. 1 shows an example of a conventional rotating magnetic head drum, with a partial new am, Fig. 2 is a bottom view of the main part, Fig. 3 is a plan view of the main part of Fig. 111, and Fig. A partial cross-sectional view of the first embodiment of the present invention, FIG. 5 is a partial cross-sectional view of I11 thereof, and FIG.
FIG. 7 is a partial cross-sectional view of the *0 third cold example of the present invention.

1...Rotating drum^, 2m, 2b...Magnetic head, 4
...Fixed drum, 5,15.35...Printed wiring board, 6...Rotating shaft, 8...Rotor magnet yoke, 9.19.29...Four-ta magnet, i1.
i6. '28... Coil, "12, 22.
32-...Multi-pole magnet, 13m, 13b, 23
m, 23b, 33m, 33b-magnet for rotational phase detection), 14, 24, 34° 44... magnetic detector,
25.45...Magnetic shielding case.

Representative Patent Attorney Michito Hiraki Fang 1 Doctor Oki 4 good Fang 2 diagram 21 Fang 3 Mouth Spear 5 O 6 Ward vinegar Dou 7 Kasumi

Claims (3)

[Claims] (1) a rotating drum, a magnetic head mounted on the rotating drum, a fixed drum, a rotating shaft that integrally rotates the rotating drum and the magnetic head, and a motor unit that applies rotational force to the rotating shaft; a frequency generator formed by nine multi-pole magnets in which the direction of magnetic force is alternately arranged in opposite directions and a wiring board provided at a position facing the magnets; and a frequency generator provided for detecting the rotational phase of the magnetic head. In the rotating magnetic head drum, the rotary phase detecting magnet is fixedly integrated with the multipolar magnet. A rotating magnetic head drum characterized by: (2) For a phase shift detection! The rotation according to claim 1, characterized in that the surface of the magnet facing the magnetic detector is provided in the same plane as the surface of the multipolar magnet facing the magnetic detector. Magnetic herad drum. (3) For 1a shift phase detection! Claim 1, characterized in that the magnet is covered with a magnetic shielding case having a radius larger than its rotation radius.
) m@magnetic head drum.