JPH0239013B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in rotary head devices.

In rotating head devices used in magnetic recording and reproducing devices (hereinafter referred to as VTRs), etc., in order to maintain the correct relative speed and position between the head and the recording medium, it is necessary to reduce lateral wobbling due to uneven rotation and vibration. Must be.

FIG. 1 is a diagram showing an example of a conventional rotary head device used in a VTR. 1 is a rotating upper cylinder, 2 and 3 are heads attached to the cylinder 1, 4 is a rotating shaft, 5 and 6 are ball bearings that rotatably support the rotating shaft 4, and 7 is a rotating shaft 4 and a cylinder 1. The coupled support member 8 is a sleeve.
The support member 7 and the sleeve 8 are provided with a surface 7 that applies a preload to prevent movement of the bearings 5 and 6 in the thrust direction.
a and 8a are provided respectively. A fixed lower cylinder 9 supports the rotary shaft 4 via bearings 5 and 6, and has a magnetic tape running surface on its outer peripheral portion 9a. 10 is a rotating side winding of the rotary transformer, and 11 is a stationary side winding, which are attached to the support member 7 and the lower cylinder 9, respectively. The rotating winding 10 is connected to the heads 2 and 3 and exchanges signals with the heads. 12 to 15 indicate surface-facing direct motors (hereinafter referred to as DD motors) that drive the rotating parts including the heads 2 and 3;
2 is a rotary magnet, 13 is a coil, 14
15 is a rotor yoke, and 15 is a stator yoke.

In a rotating head device having such a configuration, torque fluctuations occur depending on the type and amount of lubricant in the ball bearings 5 and 6, and this causes uneven rotation. In addition, the accuracy of the ball bearings 5 and 6 caused vibrations, which caused lateral vibration and other problems, which interfered with stable rotation. Further face to face
The loads applied to the upper and lower ball bearings 5 and 6 differ depending on the attraction force between the rotary magnet 12 of the DD motor and the stator yoke 15. This has the disadvantage of causing vibration and shortening the life of the entire bearing.

In view of the above-mentioned drawbacks, it is an object of the present invention to provide a rotating head device that can be configured with a small number of parts, allows easy positioning of rotating parts, does not cause vibration or lateral vibration, has a long bearing life, and does not accumulate static electricity. purpose.

FIG. 2 is a diagram showing a rotary head device which is an embodiment of the present invention. 21 is a rotating upper cylinder (rotating member); 22 and 23 are heads; 24 is a rotating shaft (rotating shaft member); and 25 and 26 are radial fluid bearings provided on the rotating shaft 24. The figure shows a bearing part 25,
This is an example in which a spiral groove is formed by etching on No. 26. 27 is a fixed lower cylinder (fixed member) having a surface facing the bearings 25 and 26 and a tape running surface on the outer periphery, and a lubricant is sealed in the gap 28 between the rotating shaft 24 and the lower cylinder 27. There is. When the rotating shaft 24 is eccentric, the fluid bearing parts 25, 2
6 generates pressure that balances the load, resulting in extremely high precision rotation.

Also, to prevent lubricant leakage, magnetic fluid (or magnetic lubricating fluid) is used to create a magnetic seal. 34 and 35 are permanent magnets, 36 and 37 are yokes, and 38 and 39 are magnetic fluids. With this configuration, a magnetic circuit shown in A in the figure is constructed, and the magnetic fluid 3
8 and 39 serve as a lubricant seal. The magnetic fluids 38 and 39 have both fluidity, which is a characteristic of a liquid, and properties of a magnetic material made of an alloy such as iron, nickel, or ferrite. 30 and 31 are a rotating side winding and a stationary side winding, respectively, of the rotary transformer.

Reference numerals 40 to 43 are torque generating sections of a surface-facing DD motor for driving the rotating head section. A rotor magnet 40 is bonded onto the rotor yoke 41. This rotor yoke 41 is fixed to the rotating shaft 24 and rotates the shaft. 42 is a coil, and 43 is a stator yoke. An adjusting screw (adjusting member) 44 is provided at the center of the stator yoke 43, that is, at the center of rotation of the rotating shaft 24.

When the rotary magnet 40 rotates, an attractive force acts between the rotary magnet 40 side and the coil 42 side, and the rotating portion including the rotating shaft 24 is urged downward in the figure.

Further, the rotating part including the rotating shaft 24 can be adjusted in the thrust direction by a screw 44, and the head 22,
You can finely adjust the height of 23. Furthermore, by constructing the screws 44, stator yoke 43, and support columns 45 (attachment members) from conductive materials, it is possible to ground static electricity generated by friction between the rotating shaft 24 and the lubricant.

As described above, according to the configuration shown in FIG. 2, in a rotary head device having a hydrodynamic bearing, a surface-facing DD is used as a drive unit, and its suction force applies an axial force to the rotating shaft 24, and the screw 44 By making it come into contact with, an appropriate load can be applied in the thrust direction. Therefore, it is possible to prevent the occurrence of vibrations, etc., and since the bearing uses a fluid bearing, the life of the bearing will not be adversely affected.
The screw 44 can also be used as a position adjusting member in the thrust direction of the rotating shaft 24, and can be used to adjust the distance between the rotary magnet 40 and the coil 42 and the position of the head 2.
The heights of 2 and 23 can also be adjusted. Furthermore, it became possible to ground the static electricity generated by the friction of the lubricant.

FIG. 3 is a diagram showing another embodiment of the present invention,
FIG. 3 is a diagram showing an example in which the present invention is applied to a rotary head device with a fixed upper cylinder.

Components that are the same as those in the embodiment shown in FIG. 2 are given the same numbers, and their explanations will be omitted. Reference numeral 52 designates a head plate (rotating member) to which heads 56 and 57 are fixed, and is fixed to a support member 58 with screws 60. 51 is a fixed upper cylinder, and screws 54,
It is fixed at 55. The rest of the structure is exactly the same as that of the embodiment shown in FIG. 2, and the same effects can be obtained. In this way, the present invention can be applied to both the upper cylinder rotating type and the upper cylinder fixed type.
To obtain a rotary head device with a long life without vibration or lateral wobbling.

In the embodiments of this specification, a magnetic fluid is used to prevent the lubricant from flowing out, but it is also possible to prevent the lubricant from flowing out by using the magnetic lubricant itself.

As is clear from the above embodiments, according to the present invention, in a rotary head device using a fluid bearing,
By applying an appropriate load to the rotating part using the force generated by the rotating drive part, it is possible to obtain a rotating head device with a long life without vibration or lateral wobbling.

Furthermore, in the rotary head device of the present invention, by using the member that applies a load to the rotary portion also as a positioning member in the axial direction of the rotary portion, the driving portion and the head can be positioned with a simple configuration. . Furthermore, it can also be used as a means for grounding static electricity generated by a hydrodynamic bearing.

[Brief explanation of drawings]

FIG. 1 shows an example of a conventional rotary head device, FIG. 2 shows an embodiment of the present invention, and FIG. 3 shows another embodiment of the invention. 21 is a rotating upper cylinder, 22 and 23 are heads,
24 is a rotating shaft, 25 and 26 are fluid bearing parts, 27 is a lower cylinder, 34 and 35 are permanent magnets, 38 and 39
is a magnetic fluid, 40 is a rotary magnet, 41
is a rotor yoke, 42 is a coil, 43 is a stator yoke, 44 is a screw, 51 is a fixed upper cylinder, 5
2 is a head plate, and 53 is a support.

Claims (1)

[Claims] 1. A fixed member, a rotating member having at least one head, a rotating shaft member that rotates integrally with the rotating member, and a fluid bearing for rotatably supporting the rotating member with respect to the fixed member. , an adjustment member for adjusting the position of the rotation member in the axial direction by making point contact with the rotation shaft member; and an adjustment member for rotationally driving the rotation member to urge the rotation shaft member in a direction to contact the adjustment member. a motor; a mounting member for mounting a stator yoke of the motor to the fixing member; the adjusting member is supported by the stator yoke of the motor; and the adjusting member, the mounting member, and the stator yoke are made of a conductive material. A rotary head device comprising: