JPH031312A - Rotary head device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Application in Business A] The present invention relates to a rotary head device, and more specifically, the present invention relates to a rotary head device, which has a fixed cylinder and a rotary cylinder that supports a magnetic head and is coaxially supported with the fixed cylinder. The present invention relates to a rotary head device for magnetically recording or reproducing information by sliding a magnetic tape of a magnetic recording medium on a cylinder and rotating a rotary cylinder.

[Prior Art] This type of rotary head device is used in a VTR (video tape recorder). Conventionally, in the rotating head device of general VTR including home VTR, for example,
As described in No. 8-190808, etc., a motor that rotationally drives the rotary cylinder is placed under a cylinder section consisting of an upper cylinder (rotating cylinder) that supports a magnetic head and a lower cylinder (fixed cylinder). Therefore, the height of the entire rotary head device inevitably became high.

On the other hand, recently, as described in Japanese Patent Application Laid-open No. 63-164014, etc., the center axes of the upper and lower cylinders are fixed axes, the upper cylinder is supported using a hydrodynamic bearing, and a cylindrical type A structure is adopted in which a rotary transformer is used and the motor is constructed on the outer periphery of the rotary transformer, and the motor is built into the upper and lower cylinders to reduce the thickness of the entire device.

However, such a structure is not suitable for a portable VTR such as a camera-integrated type because the shaft torque changes greatly depending on the temperature and increases significantly as the temperature decreases, and there is a limit to how thin the VTR can be made. A widely used VTR with an integrated camera has four heads instead of the conventional two heads, a cylinder diameter of 273 mm, and a cylinder rotation speed of 3/2 times the normal cylinder diameter.

In order to further reduce the size and thickness, recently, a configuration has been used in which the central axis is similarly fixed, a rotary transformer is disposed on the lower cylinder side, and a motor is disposed on the upper cylinder side.

[Problems to be Solved by the Invention] In the above-mentioned conventional rotary head device for VTRs, in the type in which the center shafts of the upper and lower cylinders are rotating shafts, the middle part of the shaft is supported and the upper cylinder side and the lower cylinder side rotate respectively. Since the body is provided, torsional resonance of the rotating shaft occurs. For this reason, the resonance phenomenon has been dealt with by designing the motor so that the torque ripple frequency and the resonance point are shifted, or by attaching a vibration absorbing rotor to either the upper or lower rotating body.

On the other hand, in a type where the cylinder axis is a fixed axis and the motor is installed on the upper cylinder side, the stator of the motor is fixed to the upper cylinder side end of the fixed axis via the motor pedestal.
Although the torsional resonance of the conventional rotating shaft type is eliminated, torsional vibration due to the fixed shaft and stator occurs. This torsional vibration causes uneven rotation of the motor, ie, uneven rotation of the upper cylinder, as shown in FIG. 5(A). Figure 5 (A)
shows the frequency characteristics of rotational unevenness of a conventional rotating shaft type device, and strong peaks of rotational unevenness can be seen at different rotational unevenness frequencies.

Therefore, as a countermeasure against torsional vibration of the stator that causes such uneven rotation, it may be considered to attach a vibration damper to the stator of the motor. However, if this is done, the height of the cylinder portion will increase by the height of the vibration damper. Particularly in small VTRs such as those with an integrated camera, the cylinder of the rotary head device fits into the cassette when the magnetic tape cassette is attached to the VTR, so the height of the cylinder must be kept as low as possible. It is difficult to provide a vibration damper thereon.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary head device of this type that can absorb the vibrations of the stator of the motor without increasing the height of the cylinder section.

[Means for Solving the Problems] In order to solve the above problems, the present invention includes a fixed cylinder fixed to a fixed shaft, and a rotary cylinder supporting a magnetic head and rotatably bearing on the fixed shaft. A rotary head device in which a motor for rotationally driving the rotary cylinder is provided in the rotary cylinder, and a stator of the motor is fixed to an end of the fixed shaft on the rotary cylinder side. and a second stator component are combined to form the stator of the motor, and the stator is configured to absorb vibrations via the viscoelastic body.

[Function] According to such a configuration, the stator absorbs torsional vibration caused by the fixed shaft and the stator via the viscoelastic body when the motor is rotationally driven, and uneven rotation of the rotating cylinder can be prevented from occurring. Furthermore, there is no need to separately provide a vibration absorbing damper on the stator, and the height of the cylinder portion can be reduced.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

1 Figure 1 illustrates the structure of a rotary head device according to a first embodiment of the present invention. It is assumed that this rotary head device is used in a camera-integrated VTR.

In FIG. 1, reference numeral 4 is a lower cylinder, and reference numeral 5 is an upper cylinder. During recording and reproduction, a magnetic tape of a magnetic recording medium (not shown) is wound around both cylinders 4.5 and slides. ing. The lower cylinder 4 is a fixed cylinder, and the upper cylinder 5 is a rotating cylinder that supports and rotates a 6!1 air head 8 fixed at four locations at its lower end with screws 31.

A transformer stator section 7 constituting a rotary transformer for outputting recording and reproducing signals without contacting the rotating magnetic head is fixed on the inner bottom surface of the lower cylinder 4. A hole 4b is formed in the center of the lower cylinder 4, and the fixed shaft 1 is fitted into this hole 4b and fixed. This fixed shaft 1 allows the upper cylinder 5 to
is rotatably supported.

Bearings (ball bearings) 2a and 2b are rotatably attached to the fixed shaft 1. Balls 2c of bearings 2a and 2b are rotatably fitted into grooves 1a and lb formed on the outer periphery of fixed shaft 1, respectively. That is, the bearings 2a and 2b are bearings with a shaft centered on the fixed shaft 1.

A transformer stand 3 is fitted and fixed to the outside of the bearings 2a, 2b. A transformer rotor section 6 constituting a rotary transformer is fixed to the lower surface of the transformer stand 3, and faces a transformer stator section 7 through an extremely small gap. Terminals 9 are provided protrudingly on the transformer rotor section 6, and the terminals 9 are pressed against the wiring board 8a of the magnetic head 8 fixed to the lower surface of the upper cylinder 5 to connect the transformer rotor section 6.
is connected to the magnetic head 8.

On the other hand, an upper cylinder 5 is fitted and fixed to the upper part of the transformer stand 3. That is, a cylindrical boss portion 5b is formed in the center of the upper cylinder 5, and this boss portion 5b is connected to the transformer stand 3.
is fitted onto the top of the holder and fixed.

Next, a motor for rotationally driving the upper cylinder 5 is provided inside the upper cylinder 5. This motor is composed of the following members indicated by reference numerals 10 to 21 in FIG.

First, reference numeral 11 is a drive magnet, and reference numeral 13 is a rotor yoke, which are fixed to the upper and lower surfaces of the plate 12, respectively. For installation, the magnet 11 and rotor yoke 13 are fixed within the upper cylinder 5 by tightening the plate 12 onto the boss portion 5b of the upper cylinder 5 with screws 32.

Reference numeral 10 denotes a motor pedestal, which is fixed to the end of the fixed shaft 1 on the upper cylinder 5 side by screws or a press-fit ring. A stator of the motor is fixed onto this motor pedestal 10.

The stator consists of first and second stator plates 17.18 and a plate-like or sheet-like viscoelastic body 19 made of rubber or the like, with the viscoelastic body 19 sandwiched between the first and second stator plates 17.18. 18 are laminated and bonded. 1st
A viscoelastic body 19 is bonded onto the stator plate 17 by adhesive or the like, and a second stator plate 18 is bonded onto the viscoelastic body 19 by adhesive or the like.

The first stator plate 17 is a disc-shaped double-sided through-hole circuit board. By tightening this stator plate 17 onto the motor base 10 with screws 33, the stator is fixed to the upper cylinder 5 side end of the fixed shaft 1. A coil 14 is fixed to the lower surface of the stator plate 17, and the drive magnet 1
It is facing 1.

Also, at a predetermined position on the lower surface of the stator plate 17, there is a PG that constitutes a pulse generator for detecting the rotational phase of the motor.
A coil 16 is fixed. On the other hand, the PG magnet 15 constituting the pulse generator is fixed at a predetermined position on the upper surface of the plate 12. The PG magnet 15 rotates once due to the rotational drive of the motor, and the PG
A pulse is generated from the PG coil 16 each time it passes in front of the coil 16, and the rotational phase of the motor is detected from this pulse. Further, although not shown, an FG pattern constituting a frequency generator for detecting the rotational speed of the motor is provided on the lower surface of the stator plate 17.

On the other hand, a flexible cable 22 is connected to the center of the upper surface of the stator plate 17 for connecting the motor to a motor drive control circuit (not shown) of a VTR. Coil 14. P
The G coil 16, FG pattern, etc. are connected to the flexible cable 22 via a through hole (not shown) in the stator plate 17 and a wiring pattern.

Next, the viscoelastic body 19 is shaped like a circular plate or sheet having a hole 19a in the center for avoiding the flexible cable 22.

Further, the second stator plate 18 is formed from an iron plate or the like, and similarly has a hole 18a in the center for avoiding the flexible cable 22.
A circular magnetic plate with . The stator plate 18 serves as a yoke that forms part of the magnetic circuit of the motor.

Furthermore, components of the motor indicated by reference numerals 20 and 21 in FIG. 1 are a ground terminal and a ground plate for grounding static electricity generated between the upper cylinder 5 and the magnetic tape during recording and reproduction, respectively.

The ground plate 21 is fixed to the upper surface of the transformer base 3 and is electrically connected to the upper cylinder 5 via the transformer base 3 made of conductive metal. The base end portion of the ground terminal 20 is fixed to the lower surface of the motor pedestal 10, and the tip portion 20a slidably contacts the upper surface of the ground plate 21. In this way, the upper cylinder 5 is grounded via the transformer stand 3, the ground plate 21, and the ground terminal 20.

A motor is constructed from each of the above members. During recording and reproduction of the VTR, the coil 14 is energized via the flexible cable 22 from an external motor control circuit (not shown), the coil 14 is excited, and magnetic force acts between the coil 14 and the drive magnet 11. When mounted, the plate 12 and the rotor yoke 13 are rotated, the upper cylinder 5 is rotated, and the magnetic head 8 is rotated.

Then, the magnetic head 8 slides on a magnetic tape (not shown) that is wound around the cylinder 4.5 and slides, thereby performing recording and reproduction.

According to this embodiment as described above, since the stator of the motor of the rotary head device is constructed by connecting the first and second stator plates 17 and 18 via the viscoelastic body 19, the rotational drive of the motor is Torsional vibrations sometimes generated by the fixed shaft 1 and the stator are absorbed through the viscoelastic body 19 of the stator.

That is, the stator functions as a vibration damper that absorbs vibrations via the viscoelastic body 19.

In this way, the stator absorbs vibrations when the motor is driven, thereby suppressing uneven rotation when the motor is driven, as shown in FIG. 5(B). That is, FIG. 5(B) shows the frequency characteristics of the rotational unevenness of the device of this embodiment, and in this case, FIG. 5(A) shows the frequency characteristics of the rotational unevenness of the conventional device.
The peak of uneven rotation like this is gone.

Furthermore, according to this embodiment, since vibrations can be absorbed by the stator, there is no need to provide a separate vibration absorbing damper on the stator, and the height of the cylinder can be kept low, resulting in a more compact VTR incorporating a rotating head device. , which can contribute to thinning.

11 11 Next, FIG. 2 shows the structure of a rotary head device according to a second embodiment of the present invention. The device of this embodiment is a partially modified structure of the device of the first embodiment described above. In FIG. 2, parts common or corresponding to those in FIG. 1 are given the same reference numerals, and explanations of the common parts will be omitted. The same applies to the third embodiment described later.

As shown in FIG. 2, the stator of the motor also includes first and second stator plates 17, 18 and a viscoelastic body 19.
, with a viscoelastic body 19 in between, and
It is constructed by joining stator plates 17 and 18.

Here, the difference from the first embodiment is that the first stator plate 1
7 is a magnetic plate such as an iron plate. A flexible printed circuit board 23 for wiring the coil 14, PG coil 16, etc. is fixed to the lower surface of the stator plate 17.

Ends 23a and 23b of the flexible printed circuit board 23 are bent upward along the outer periphery of the stator plate 17, 18,
It is joined to the upper surface of the second stator plate 18.

The second stator plate 18 is a substrate for wiring,
It is assumed that a wiring pattern (not shown) for connecting the flexible printed circuit board 23 to the flexible cable 22 is formed on its upper surface. A terminal pattern (not shown) formed on the ends 23a and 23b of the flexible printed circuit board 23 is connected to a wiring pattern on the stator plate 18, and the flexible cable 2 is connected to the wiring pattern on the stator plate 18 through the pattern.
Connected to 2. The flexible cable 22 is coupled to the upper surface of the second stator plate 18 by soldering or the like and connected to its wiring pattern.

With this structure, the stator can absorb vibrations through the viscoelastic body 19 as in the case of the first embodiment, and the same effect can be obtained.

Third Embodiment Next, FIG. 3 shows the structure of a rotary head device according to a third embodiment of the present invention.

As shown in FIG. 3, in this embodiment, the first stator plate 1
The diameter of the stator plate 7 is significantly smaller than that in the first and second embodiments, and is large enough that the outer edge of the stator plate 17 protrudes only a little from the outer edge of the motor pedestal 10 to which the stator plate 17 is fixed. A viscoelastic body 19 is fixed to the outer periphery of the stator plate 17.

The viscoelastic body 19 is formed into a cylindrical shape with a short wall thickness. Then, the stator plate 17 is fitted inside the lower part of the viscoelastic body 19,
The second stator plate 18 is fitted and fixed to the upper outer side of the viscoelastic body 19.

The diameter of the hole 18a at the center of the stator plate 18 is slightly smaller than the outer diameter of the stator plate 17, and the viscoelastic body 19 is arranged so that the inner edge of the stator plate 18 overlaps the outer edge of the stator plate 17. Intermediate stator plate 17.
18 are combined. The viscoelastic body 19 is the stator plate 17
, 18 by outsert molding or the like.

The stator plate 18 is a magnetic plate constituting a yoke, and a flexible printed circuit board 23 for wiring the coil 14, PG coil 16, etc. is fixed to the lower surface of the stator plate 18. Ends 23a, 2 of flexible printed circuit board 23
3b is bent along the outer periphery of the stator plate 18 and joined to the upper surface of the stator plate 18. A wiring pattern (not shown) for connecting the flexible printed circuit board 23 to the flexible cable 22 is formed on the upper surface of the stator plate 18, and the connection is made in the same manner as in the second embodiment.

The structure of this embodiment as described above also allows the stator to absorb vibrations via the viscoelastic body 19, and the same effects as in the first and second embodiments can be obtained.

1 Earthshake 1 Next, FIG. 4 shows the structure of a rotary head device according to a fourth embodiment of the present invention.

As shown in FIG. 4, in this embodiment, the second stator plate ■8
is fixed to the motor pedestal 10 with screws 33, and a flexible printed circuit board 23 is fixed as a first stator plate to the lower surface of the stator plate 1B via a plate-shaped viscoelastic body 19. There is. A coil 14 and a PG coil 16 are fixed to the lower surface of the flexible printed circuit board 23, and an FG pattern (not shown) is provided, and respective wiring patterns are formed.

End portion 23a of flexible printed circuit board 23.

23b is folded back along the outer periphery of the stator plate 18 and joined to the upper surface of the stator plate 18. A wiring pattern (not shown) for connecting the flexible cable 22 and the flexible printed circuit board 23 is provided on the upper surface of the stator plate 18, and the connection can be made in the same manner as in the second and third embodiments. It will be done.

With the structure of this embodiment as well, the stator can absorb vibrations via the viscoelastic body 19 as in the first to third embodiments, and the same effects can be obtained.

[Effects of the Invention] As is clear from the above description, the present invention includes a fixed cylinder fixed to a fixed shaft, and a rotary cylinder supporting a 61 air head and rotatably bearing on the fixed shaft. ,
A rotary head device in which a motor for rotationally driving the rotary cylinder is provided in the rotary cylinder, and a stator of the motor is fixed to an end of the fixed shaft on the rotary cylinder side,
The stator of the motor is configured by connecting the first and second stator components via a viscoelastic body, and the stator is configured to absorb vibrations via the viscoelastic body, so that when the motor is driven to rotate, The stator absorbs the torsional vibration caused by the fixed shaft and stator through the viscoelastic body, preventing the occurrence of uneven rotation and ensuring good recording and playback.Moreover, the height of the cylinder can be lowered, making it ideal for equipment incorporating a rotating head device. The excellent effect of contributing to miniaturization and thinning can be obtained.

[Brief explanation of the drawing]

1 to 4 are longitudinal cross-sectional views showing the structures of rotary head devices according to the first to fourth embodiments of the present invention, respectively, and FIGS. FIG. 4 is a diagram showing frequency characteristics of rotational unevenness of the head device and the device of the example. 1...Fixed shaft 2a, 2b...Bearing 3...
・Transformer stand 4...Lower cylinder 5...Upper cylinder 6...Transrotor section 7...Transformer stator section 8...Magnetic head 10...Motor pedestal 11.
... Drive magnet 12 ... Mounted on plate 13 ... Rotor yoke 14
...Coil 15...PG magnet 16.
・-PG coil 17...first stator plate 18・
...Second stator plate 19...Viscoelastic body 22...Flexible cable 23...Flexible printed circuit board

Claims (1)

[Claims] 1) It has a fixed cylinder fixed to a fixed shaft, and a rotating cylinder that supports a magnetic head and is rotatably supported by the fixed shaft, and a motor that rotationally drives the rotating cylinder is provided in the rotating cylinder, In a rotary head device in which a stator of the motor is fixed to an end portion of the fixed shaft on the rotating cylinder side, the stator of the motor is configured by connecting first and second stator constituent members via a viscoelastic body; A rotating head device characterized in that the stator is configured to absorb vibrations through the viscoelastic body.