JPH0115929B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor-directly connected rotary magnetic head device for a helical scan VTR.

FIG. 1 is a diagram showing an example of a conventional motor-directly coupled rotary magnetic head device. The motor-directly coupled rotating magnetic head device is composed of a rotating section that rotates the magnetic heads 1a and 1b, and a fixed section that supports the rotation, and the fixed section incorporates a motor that drives the rotating section. The rotating part is composed of a rotating cylinder 4, a rotating shaft 6, and a stopper 5 for preventing the shaft from coming off. A magnetic head 1 is mounted on the bottom surface of the rotating cylinder 4.
Head plates 2a and 2b provided with screws 3a and 1b are
It is attached by a and 3b. The rotating cylinder 4 is attached to a rotating disk 7 fixed to the shaft 6 with screws 8a and 8b in order to facilitate its removal. The fixed part includes a fixed cylinder 11 fixed to a chassis 10 disposed below the rotating part by screws 9a and 9b, and bearings 12a and 1 that pivotally support the shaft 6.
2b.

The motor that generates the rotational force of such a rotating magnetic head device is housed in a fixed cylinder 11 and fixed to the center of the shaft 6, and has a rotor consisting of a magnet 13 and a rotor yoke 14, which rotate together with the shaft 6. , a motor coil 15 mounted opposite to the upper surface of the magnet 13 of the rotor, and a stator yoke 1.
It consists of a stator consisting of 6 pieces. The so-called motor is a flat-faced brushless motor. The motor coil 15 and the stator such as the stator yoke 16 are fixed to a plate 17, which is secured by screws 18.
It is fixed to the upper part of the fixed cylinder 11 by a screw. Rotor yoke 14 and magnet 13 of the rotor
is fixed to the shaft 6 with adhesive, so the magnet 13
The rotational force generated by the motor coil 15 reliably turns the rotating cylinder. Signal transmission between the rotating magnetic heads 1a and 1b and an electric circuit (not shown) is carried out by a rotor transformer 19, which is a rotary signal transmitter that is fixed to the lower part of the rotating disk 7 and rotates integrally with the rotating disk. This is done by electromagnetic coupling between the stator transformer 20, which is a non-rotating signal transmitter, and the stator transformer 20, which is a non-rotating signal transmitter bonded to the plate 17 fixed to the fixed cylinder 11. Signals from the magnetic heads 1a, 1b transmitted from the rotor transformer 19 to the stator transformer 20 by electromagnetic coupling are transmitted to a signal processing circuit (not shown).

In this way, the conventional motor-directly connected rotating magnetic head device has bearings 12a, 12b, rotor transformer 1,
9. The stator transformer 20 and the motor section are stacked one after another as shown in the figure. Therefore, in order to make a rotating magnetic head device having such a structure thin and short, each component must be made thin or the distance between the two bearings 12a and 12b must be shortened. However, if the rotating disk 7 is made thinner,
It cannot be made thinner because its processing accuracy is poor. Further, making the rotor transformer 19, stator transformer 20, motor coil 15, and magnet 13 thinner deteriorates their respective characteristics. Also bearing 12
If the distance between a and 12b is shortened, the inclination of the shaft 6 will increase. That is, as shown in Figure 2,
When the bearing 12b is shifted to the position 12b' to shorten the distance between the bearings, the inclination of the shaft 6 increases. axis 6
When the magnetic heads 1a and 1b fall down, the heights of the magnetic heads 1a and 1b change depending on the rotational phase, and the center of rotation changes. That is, since the scanning of the tape 36 by the magnetic heads 1a and 1b loses linearity, a problem arises in that the compatibility of the tape 36 becomes poor.

Therefore, with the structure shown in FIG. 1, it has been difficult to create a thin and short motor-directly coupled rotary magnetic head device due to problems such as deterioration of the performance of each component and the collapse of the shaft 6.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor-directly connected rotary magnetic head device which eliminates the above-mentioned drawbacks of the prior art and can be made significantly thinner.

The main point of the present invention is that rotating parts are provided at the upper and lower parts of the rotating shaft, a signal transmitter is fixed to one rotating part, a motor rotor is fixed to the other rotating part, and the signal transmitter is provided between the upper and lower rotating parts. A signal transmitter facing the transmitter and upper and lower bearings supporting the rotating part are provided, the signal transmitter is arranged in parallel with the bearings, and the signal transmitter and the head body are arranged between the upper and lower bearings. This allows the rotating magnetic head device to be made thinner and shorter.

Embodiments of the present invention will be described below based on the drawings. FIG. 3 is a sectional view of a main part of an embodiment of the motor-directly coupled rotating magnetic head device of the present invention. This device consists of a rotating part for rotating the rotating magnetic heads 1a and 1b and a fixed part for supporting the rotation. This rotating part is fixed to the upper part of a rotating cylinder 21 and a rotating shaft 23, and is made up of a square-shaped rotating disk 22 to enable replacement of the cylinder 21, and screws 29a, 29b connecting them. , a rotor magnet 24 fixed to the lower part of the rotating shaft 23, and a rotor plate 3.
It consists of a lower rotating part such as 0. As shown in the figure, the lower surface of the rotating cylinder 21 is provided with a head plate 2a, which is provided with rotating magnetic heads 1a and 1b as head bodies.
2b is attached with screws 3a and 3b.
A rotor transformer 33 is attached to the rotating disk 22. The upper rotating part and the lower rotating part are integrated by a shaft 23 for simultaneous rotation. The fixed part is installed between the upper rotating part and the lower rotating part and is attached to the shaft 23.
A fixed cylinder 26 fixed to a chassis 25 arranged in the center of the motor holder 3 fixed to the lower circumferential surface of the cylinder with screws 29c and 29d.
It starts from 1. The fixed cylinder 26 has a thin bearing cylinder part 26b extending along the shaft 23 and a piece extending outward from the center of the cylinder part facing the upper rotating part, and houses and fixes the stator transformer 34 facing the rotor transformer 33. It consists of a transformer storage cylinder part 26d and a thick motor holder fixing cylinder part 26a extending from the lower part of the storage cylinder part. The bearing cylinder portion 26b of the fixed cylinder 26 has bearings 35a, 35.
It is fixed to the rotating shaft 23 via the rotor transformer 33, and a part of the rotor transformer 33 is inserted into the annular space S formed by the rotor transformer 33. Projections 26c for holding the bearings 35a and 35b are formed at the upper and lower ends of the bearing cylinder. A motor coil 28 is fixed to the motor holder 31 via a stator yoke 27, which is arranged to face the rotor magnet 24 of the lower rotating section.

32 is a square-shaped shield case fixed to the motor holder 31, and shields the stator yoke 27, motor coil 28, rotor magnet 24, etc. The bearings 35a, 35b are located between the upper rotating part and the lower rotating part to support these rotating parts, and the two bearings 35a, 35b are arranged at the same spacing as in the conventional case. Therefore, the inclination of the shaft 23 does not become larger than in the conventional case. Further, by arranging the magnetic heads 1a, 1b inside the space 1 between the upper and lower bearings, the rotation performance of the magnetic heads 1a, 1b is improved, and the linearity of tape running can be improved.

The first feature of this embodiment is a rotary signal transmitter (rotor transformer) for transmitting at least a video signal between the two bearings 35a and 35b.
33, a non-rotating signal transmitter (stator transformer) 34 is disposed, a motor coil 28 serving as a motor stator is disposed, and a rotating surface of the head body is disposed. Here, if L is the length of the non-rotating signal transmitter 34 (upper surface) and the motor coil 28 (lower surface) which is the motor stator, then L<l in this embodiment. As a result, necessary components for the rotating magnetic head device can be arranged without shortening the distance l between the bearings.

The second feature is that a protruding portion (convex) having different thicknesses, that is, a motor holder fixing cylinder portion 26a and a bearing cylinder portion 26b, are provided in a stepped manner at the lower part of the fixed cylinder 26. Here, the thick protruding portion of the fixed cylinder portion 26a can be used for chucking when the fixed cylinder 26 is lathed.
Further, a thin protrusion at the tip of the bearing cylinder portion 26b is for holding the bearing 35b. By using this thick protrusion for chucking during machining, it is possible to prevent deformation of the lower side of the bearing cylinder 26b, and also to prevent deformation of the positioning part 26f of the fixed cylinder 26 relative to the chassis 25. Installation can be performed with high precision. Furthermore, the lower protrusion and upper protrusion of the bearing cylinder portion 26b and the outer peripheral surface of the fixed cylinder 26, which serves as the tape guide surface, can be simultaneously machined with one member. As a result, the rotating shaft 23 and the fixed cylinder 26
The tape guide surface of the tape can be made parallel (coaxiality) with high accuracy, and the mounting accuracy on the chassis 25 can be also improved.
The straightness of the tape guide surface and the rotating shaft 23 relative to 5 can be made good. Furthermore, a motor coil 28, which is a motor stator, is arranged close to the thin-walled protrusion that protrudes from the thick-walled protrusion, and the motor coil 28 is arranged to surround the thin-walled protrusion. Therefore, it is possible to extend the bearing 35b downward. Furthermore, since the fixed cylinder 26 is provided with a protrusion 26c on the upper part thereof that holds a bearing 35a that can be inserted into the center hole of the signal transmitter 33, 34, the first feature described above can be implemented.

Furthermore, although a planar brushless motor is used as the motor in the embodiment shown in FIG. 3, other types of motors may be used. An example thereof is shown in FIG. 4 as another embodiment of the present invention. The motor shown in FIG. 4 is of a coreless type and is composed of a fixed portion consisting of a motor coil 36, a motor rotor of a rotor plate 37, a holder 39, and a stator magnet 38. In the case of the motor shown in Fig. 4, the length of the rotating and non-rotating signal transmitter 34 (upper surface) and the stator magnet 38 (lower surface), which is the motor stator, is L.
In this case, the structure has the condition that l>L as in the example shown in FIG. Two more bearings 35a, 35b
Signal transmitters 33, 34 and a stator magnet 38, which is a motor stator, are arranged between them in the same manner as in FIG. That is, in the example of FIG. 4, as in the example of FIG. 3, a thin and rectangular rotating magnetic head device can be constructed without shortening the bearing spacing l.

According to the present invention described above, the bearing cylinder portion can be configured to protrude in the vertical direction of the fixed cylinder, and the upper bearing can be disposed in the direction approaching the rotating cylinder,
As a result, it is possible to provide a thin and rectangular motor-directly connected rotary magnetic head device. By integrating the bearing cylinder part and fixed cylinder,
It is possible to precisely configure the parallelism between the rotating shaft and the fixed cylinder. Furthermore, since the head body is disposed inside the space between the upper and lower bearings, the rotational performance of the head body is improved, and the linearity of tape scanning can be improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main parts of a conventional motor-directly coupled rotating magnetic head device, FIG. 2 is a front view showing the relationship between the rotating shaft and the bearing, and FIG. 3 is a diagram of the motor-directly coupled rotating magnetic head device of the present invention. A sectional view of main parts showing one embodiment,
FIG. 4 is a sectional view of a main part showing another embodiment of the present invention. 21: Rotating cylinder, 22: Rotating disk, 23:
Shaft, 24: Rotor magnet, 25: Shaft, 2
6: Fixed cylinder, 27: Stator yoke, 2
8: Motor coil, 30: Rotor plate, 3
1: Motor holder, 32: Shield case, 3
3: Rotor transformer, 34: Stator transformer,
35: Bearing.

Claims (1)

[Scope of Claims] 1. A motor-directly coupled rotating magnetic head device comprising a rotating part fixed to the rotating shaft of a motor and a fixed part disposed opposite to the rotating part, wherein the rotating part is fixed to the rotating shaft. an upper rotating member including a rotating cylinder fixed to the upper part of the rotating member; a rotating signal transmitter fixed to the rotating member; and a lower rotating member including a motor rotor fixed to the lower part of the rotating shaft; a fixed member disposed between the upper rotating member and the lower rotating member, the fixed member including a fixed cylinder fixed to the rotating shaft via first and second bearings, and fixed to the fixed member; The fixed cylinder includes a non-rotating signal transmitter disposed opposite to the rotary signal transmitter and a motor stator disposed opposite to the motor rotor, and the fixed cylinder
A bearing cylinder part having a built-in bearing and protruding in the vertical direction of the fixed cylinder along the rotation axis is integrally formed, and the first and second bearings are arranged so that the rotation signal transmitter and the head body rotation surface are connected to the rotation surface of the fixed cylinder. 1. A rotary magnetic head device directly coupled to a motor, characterized in that it is disposed between a second bearing. 2. The motor-directly coupled rotating magnetic head device according to claim 1, wherein the lower portion of the bearing cylinder portion is formed in a convex shape. 3 The first and second bearings have a distance between the first bearing and the second bearing, L, and a distance L between the upper surface of the non-rotating signal transmitter and the lower surface of the motor stator. A motor-directly coupled rotary magnetic head device according to claim 1, characterized in that the head device is arranged such that when L<l.