JPH0495206A - Rotary head device - Google Patents

Abstract

PURPOSE:To obtain a thin and compact rotary head device by sealing a lubricant fluid into a gap formed between a fixed rotary transformer and a revolving rotary transformer which constitute a rotary transformer which performs the transfer of signals in order to secure the function of a dynamic pressure type fluid bearing. CONSTITUTION:A fixed drum 1 having a tape type recording medium leading groove 13 on its outer peripheral surface is provided together with a fixed rotary transformer 3 stuck onto the same axis as the drum 1, and a revolving rotary transformer 4 which is set rotatably and opposite to the transformer 3 on its the same axis via a gap sealing a lubricant fluid. Furthermore a head 5 is added to perform the transfer of signals to the recording medium together with a rotary drum 2 which revolves together with the transformer 4 holding the head 5, and a thrust bearing means 6 which keeps the relative height between both drums 1 and 2 at a prescribed level in the center axis direction. In such a constitution, the outer peripheral diameters of both transformers can be reduced and the thickness of a rotary head device can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application' The present invention relates to a rotary head device used in a video tape recorder (hereinafter referred to as a VTR).

BACKGROUND OF THE INVENTION In recent years, magnetic recording and reproducing devices using rotary head devices have been made smaller and lighter as well as higher in performance and higher quality.

Therefore, there is an increasing need for the rotary head device, which is the heart of the device, to be equipped with heads of many channels and to be made smaller.

The demand for miniaturization has become particularly strong for VTRs with built-in cameras and the like. In addition, regarding multi-channeling, camera-integrated VTRs have 4 heads for standard mode,
In some cases, a total of 9 heads are installed, 4 heads for long-time mode and 1 head for flying erase.

An example of a conventional rotary head device will be described below with reference to the drawings.

FIG. 4 is a sectional view of a conventional rotary head device.

The shaft 21 is rotatably supported by the fixed drum 1 via a bearing 20. Further, a disk 22 is press-fitted into the upper end of the shaft 21. This disk 22
A rotating drum 2 carrying a head 5 is fixed to.

The fixed rotary transformer 3 has a plurality of outer peripheral grooves around which coils are wound, and is coaxially fixed to the fixed drum 1. The rotating side rotary transformer 4 has a plurality of inner circumferential grooves in which fill is wound, and is fixed to the disk 22. The rotating rotary transformer 4 is coaxial with the fixed rotary transformer 3, and is arranged opposite to the fixed rotary transformer 3 with a predetermined gap (usually several tens of micrometers) in between.
It becomes possible to rotate integrally with the rotating drum 2. Stator part 2
3 holds a coil and is fixed to the fixed drum 1. Further, the rotor portion 24 is fixed to the shaft 21 by a magnet 8.

Problems to be Solved by the Invention However, in the configuration of the above-mentioned conventional rotary head device,
There were issues listed below.

Since the motor section is located below the fixed drum, it cannot be made thin.

In order to configure the motor section inside the fixed drum and the rotating drum, the outer diameter of the bearing section and the rotor lance is large, and the opposing area between the magnet and the armature coil of the motor section is small. Therefore, it becomes difficult to obtain the necessary driving force. This is especially true if the drum diameter becomes smaller.

The present invention solves the above-mentioned conventional problems, and aims to reduce the number of parts and provide a small, thin, and high-performance rotary head device.

Means for Solving the Problems In order to solve the above problems, the rotating head device of the present invention has the following features:
A fixed drum having a lead groove on its outer circumferential surface for guiding a tape-shaped recording medium, a fixed rotor IJ coaxially fixed to the fixed drum, and a fixed rotary lance coaxially with the fixed rotary transformer. What is a transformer? A rotary transformer on the rotary side that is rotatably arranged opposite to each other with a gap sealed with lubricating fluid, a head that sends and receives signals to and from the tape-shaped recording medium, and a rotary transformer that carries the head and is integrated with the rotary transformer on the rotary side. The rotary drum is configured with a rotating drum that rotates, and thrust bearing means that maintains the relative height of the fixed drum and the rotating drum in the direction of the central axis at a predetermined value.

Effect: With the above configuration, the outer diameter of the rotary transformer can be made small, and the motor can be constructed between a fixed drum and a rotating drum while ensuring a sufficient opposing area between the magnet and armature coil of the motor. Become.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of the rotary head device of the present invention. In FIG. 1, a fixed drum 1 has a lead groove 13 on its outer circumferential surface for guiding a magnetic tape. The rotating drum 2 carries a head 5. The fixed side rotary transformer 3 has a plurality of outer circumferential grooves 14 around which coils (not shown) are wound.
It is coaxially fixed to the stationary drum 1 with a. The rotating side rotary transformer 4 has a plurality of inner circumferential grooves 15 around which coils (not shown) are wound, and is coaxially fixed to the rotating drum 2. Also, this rotating side rotor IJ) lance 4
is coaxial with the fixed rotary transformer 3, is arranged opposite to the fixed rotary transformer 3 through a predetermined gap in which lubricating fluid is sealed, and is rotatably supported integrally with the rotating drum 2. There is. In other words, the opposing surfaces of the stationary rotary transformer 3 and the rotating rotary transformer 4 function not only for transmitting and receiving signals but also as a hydrodynamic bearing. The thrust bearing 6 is slidably abutted on the tip of the stationary rotary transformer 3 and is fastened to the rotating drum 2. Note that the height of the head 5 is determined by the height of the tip of the fixed rotary transformer 3. The rotor portion 7 is fastened to the rotating drum 2 by fixing an annular magnet 8 which is magnetized with a plurality of poles in the direction of the central axis. The rotating yoke 9 is arranged to face the magnetized surface of the rotor section 7 with a predetermined gap in the axial direction, and is fixed to the rotor section 7 so that it can rotate integrally with the rotor section 7.

The stator section 10 is made of a non-magnetic material, is disposed between the rotor section 7 and the rotating yoke 9 with a predetermined gap, and has an armature coil. The holding member 11 is attached to the stator section 10
is held and fixed to the fixed drum 1. The attraction plate 12 is made of a magnetic material, and the rotor portion 7 is urged in the direction of the arrow X by the attraction force generated by the magnetic force between the attraction plate 12 and the magnet 8 . Further, the height of the head 5 and the height of the magnetized surface of the magnet 8 are determined by the accuracy of processing and mounting of the tip of the fixed rotary transformer 3.

The operation of the rotary head device configured as described above will be described below.

First, when a predetermined current is passed through a coil of a magnetic circuit consisting of a coil disposed in the stator section 10 and a magnet 8 fixed to the rotor section 7, a magnetic field is generated, which causes the rotor section 7 to
rotates integrally with the rotating drum 2. Further, the opposing surfaces of the stationary rotary transformer 3 and the rotating rotary transformer 4 function as hydrodynamic bearings while transmitting and receiving signals.

As described above, by sealing the lubricating fluid in the gap between the stationary rotary transformer and the rotating rotary transformer, the following effects can be obtained.

By using the rotary transformer as a hydrodynamic bearing, a shaft and ball bearings are no longer required, making it possible to reduce the number of parts.

In addition, by reducing the space in the bearing section, the diameter of the rotary transformer can be made smaller, and the motor section can be configured inside the rotating drum and fixed drum while ensuring the facing area between the magnet and the coil, allowing the rotary head device to be made thinner. .

Furthermore, since the amount of the gap between the stationary rotary transformer and the rotating rotary transformer in which the lubricating fluid is sealed is made smaller than before (approximately 5 μm), transmission characteristics and crosstalk characteristics can be improved.

In addition, in Figure 1, the outer circumferential groove on the fixed side rotary transformer is
Further, although the rotary transformer on the rotating side has an inner circumferential groove, as shown in FIG. 2, the rotary transformer on the stationary side may have an inner circumferential groove and the rotary transformer on the rotating side may have an outer circumferential groove.

Further, although the rotary transformer shown in FIG. 1 is of a circumferentially opposed type, it may be of a surface-sealed type as shown in FIG. The thrust bearing means in the embodiment shown in FIG. 3 is constructed by sealing lubricating fluid on the axially opposing surfaces of the rotor IJ' lances. Further, the thrust plate 30 is a dustproof plate.

Effects of the Invention As described above, the rotating head device of the present invention seals lubricating fluid in the gap between the stationary rotary transformer and the rotating rotary transformer that constitute the rotary transformer that sends and receives signals. Compact design with excellent rotational performance, transmission characteristics, and crosstalk due to the structure that also functions as a bearing.

This makes it possible to realize a thin rotary head device.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a rotary head device in a first embodiment of the present invention, FIG. 2 is a sectional view of a rotary head device in a second embodiment of the present invention, and FIG. 3 is a sectional view of a rotary head device in a third embodiment of the present invention. A cross-sectional view of the rotary head device in the embodiment, and FIG. 4 is a cross-sectional view of a conventional rotary head device. 1... Fixed drum, foot side rotary transformer, lance, 5... Head,

Claims (1)

[Scope of Claims] A fixed drum having a lead groove on its outer circumferential surface for guiding a tape-shaped recording medium, a fixed rotary transformer coaxially fixed to the fixed drum, and a fixed rotary transformer coaxially fixed to the fixed rotary transformer. , and the stationary rotary transformer includes: a rotating rotary transformer rotatably arranged opposite to each other with a gap in which a lubricating fluid is sealed; a head that sends and receives signals to and from the tape-shaped recording medium; and a head that carries the head; A rotating head device comprising: a rotating drum that rotates integrally with the rotating side rotary transformer; and thrust bearing means that maintains a relative height of the fixed drum and the rotating drum in a central axis direction at a predetermined value. .