JPS647461Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in making the cylinder of a video tape recorder (hereinafter referred to as VTR) thin.

In recent years, there has been a demand for smaller devices, especially in home VTRs, and there is also a need to make the cylinder, which is one of the components of the VTR, thinner.

Conventionally, the cylinder of a VTR was as shown in Figure 2.
A shaft 21 is rotatably attached to the center of the lower cylinder 3 by a pair of ball bearings 40 and 41, an upper cylinder 2 is provided above the lower cylinder, and both cylinders 2 and 3 are connected by a fixing fitting 20. A flywheel 82 and a head disk 81 are fixed to the upper end of the shaft 21, and a head tip 7 is provided protruding from the outer periphery of the head disk 81 to face the slit between the upper and lower cylinders 2 and 3.

Further, a drive motor 50 consisting of a rotor 50b and a stator 50a is disposed between the flywheel 82 and the lower cylinder 3, and furthermore, a drive motor 50 consisting of a rotating part 6a and a stationary part 6b is arranged between the head disk 81 and the upper cylinder 2. A rotary transformer 6 is provided.

In order to make the VTR cylinder thinner, each of the cylinder components mentioned above can be made thinner.
This method has already reached its limits. One of the reasons for this is that the two ball bearings 40, 4 that support the shaft 21
This is because the interval between 1s cannot be made below a certain value.

Since the VTR records and reproduces high frequency signals on magnetic tape, the head disk 81 is rotated at high speed and with high precision. This requires that the shaft 21 be supported reliably, and this is why there is a limit to the distance between the two ball bearings.

In addition, in the cylinder of the conventional structure shown in Fig. 2,
Since the head disk 81 and flywheel 82 are fixed to the upper half of the shaft 21 and the lower half of the shaft is supported by a pair of ball bearings, the length of the shaft 21 is the same as that of the head disk 81. In addition, the thickness of the flywheel 82, the thickness of the bearing itself, and the distance between the two ball bearings 40, 41 had to be increased. This is
This is the second reason why VTR cylinders have been prevented from becoming thinner.

(Purpose) The purpose of the present invention is to improve the structure of the conventional VTR cylinder and make it even thinner.

(Structure) A cylindrical shaft portion 30 is provided in the center of the internal space of the cylinder body 9 formed by fixing the upper cylinder 2 and the lower cylinder 3 to each other, and the inner ring 4a of the rolling bearing 4 is fitted into the shaft portion. The fixed outer ring 4b of the rolling bearing 4 is fitted with the head disk 8 and rotatably supports the head disk 8 on the shaft portion 30. The head disk 8 includes a generally disc-shaped main body 84 and a rim body 83 protruding along the outer circumferential edge of the main body, and there is a mutual gap between the outer circumferential surface of the rim body 83 and the inner circumferential surface of the cylinder body. A pair of repulsive magnets 1a and 1b are arranged concentrically with the cylinder shaft portion 30, and one magnet is attached to the rim body 83 of the head disk.
The other magnets are each fixed to the cylinder body, with their repelling surfaces facing each other with a slight gap therebetween.

(Function) The head disk 8 is supported by the rolling bearing 4 and rotates about the cylinder shaft portion 30 together with one magnet fixed to the head disk. At this time, the head disk 8 rotates at a stable speed due to the effect of a sufficiently large moment of inertia due to the structure having the rim body 83 on the outer peripheral edge and the attachment of the magnet.

The rolling bearing 4 restrains the movement of the head disk 8 in the radial and axial directions, and the pair of magnets 1a,
1b repel each other and act to hold the central axis of the head disk 8 on the central axis of the cylinder body. A slight rotational wobbling that occurs when the head disk 8 rotates is suppressed by the repulsive force of these magnets.

(Special Effects) In the conventional cylinder, the head disk is fixed to the shaft, and the shaft is supported at two points by a pair of rolling bearings, whereas in the VTR cylinder of the present invention, the head disk 8 is fixed to the shaft, and the shaft is supported at two points by a pair of rolling bearings. Since the bearing is mounted directly on the shaft portion 30 of the cylinder, there is no need to increase the thickness of the bearing itself or the distance between the bearings in addition to the thickness of the cylinder body, and the cylinder body can be made significantly thinner.

The present invention will be described in detail below based on the illustrated embodiments.

The VTR cylinder of this invention is as shown in Figure 1.
A head disk 8 is housed inside a cylinder body 9 consisting of an upper cylinder 2 and a lower cylinder 3, and a head chip 7 is provided protruding from the outer periphery of the head disk 8 to rotate the head disk 8, thereby tracking a magnetic tape. This is what we do.

A cylindrical shaft portion 30 is protruded from the center of the inner surface of the lower cylinder 3, and the upper cylinder 2 is attached to the tip of the shaft portion.
The center portions of the inner surfaces of the cylinders 2 and 3 are engaged with each other, and both cylinders 2 and 3 are fixed to each other by screws 90.

The inner ring 4a of the rolling bearing 4 is fitted into the tip of the cylinder shaft 30. head disk 8
is an integrally molded product consisting of a substantially disc-shaped main body 84 and a cylindrical rim body 83 protruding along the outer peripheral edge of the main body, and has a cylindrical through hole in the center, and the inner edge of the through hole is fitted and fixed to the outer ring 4b of the rolling bearing 4, and the head disk 8 is rotatably mounted on the shaft portion 30 of the cylinder body. A head tip 7 is provided protruding from the outer periphery of the head disk 8 and faces the slit between the upper cylinder 2 and the lower cylinder 3.

Between the outer circumferential surface of the rim body 83 of the head disk 8 and the inner circumferential surface of the lower cylinder 3, two large and small ring-shaped magnets 1 that repel each other are arranged concentrically with the cylinder shaft portion 30. The smaller magnet 1b is fitted and fixed to the rim body 83 of the head disk 8,
The larger magnet 1a is fixed to the lower cylinder 3, and the repelling surfaces of both magnets face each other with a slight gap therebetween.

Further, a flat opposed coreless motor 5 consisting of a rotor 5b and a stator 5a is arranged between the upper surface of the head disk 8 and the inner surface of the upper cylinder 2, and the rotor is fixed to the head disk and the stator to the upper cylinder.

Furthermore, the lower surface of the head disk 8 and the lower cylinder 3
A rotary transformer 6 consisting of a rotating part 6b and a stationary part 6a is arranged between the rotary part 6b and the inner surface of the rotary part 6a, with the rotating part fixed to the head disk and the stationary part fixed to the lower cylinder.

In addition, the stator 5b of the motor 5 and the pair of magnets 1
is magnetically shielded so as not to affect the head chip 7.

The head disk 8 is supported by a rolling bearing 4 and is rotatable about a cylinder shaft 30, and is rotationally driven by the operation of the motor 5. At this time, the rotor 5b of the motor 5, the head chip 7, the rotating part 6b of the rotary transformer 6, and the small diameter magnet 1b rotate together with the head disk 8. The head chip 7 tracks a magnetic tape (not shown), and the rotary transformer 6 performs input/output to the head chip.

The head disk 8 rotates at a stable speed due to the effect of a sufficiently large moment of inertia due to the structure having a rim body 83 on the outer peripheral edge and the attachment of the magnet 1b.

The rolling bearing 4 restrains the movement of the head disk 8 in the radial and axial directions, and the pair of magnets 1a,
1b repel each other and act to hold the central axis of the head disk 8 on the central axis of the cylinder body 9. A slight rotational wobbling that occurs when the head disk 8 rotates is suppressed by the repulsive force of these magnets, and the head disk 8 rotates with high precision.

The VTR cylinder of this invention eliminates the shaft support structure of conventional cylinders, directly supports the head disk with a single rolling bearing, and completely suppresses rotational vibration of the head disk using the repulsive force of the magnet. By adopting this structure, it became possible to make the entire cylinder thinner.

Further, in the present invention, the fixing fittings for the upper cylinder and lower cylinder in the conventional structure are unnecessary, and no shaft is used. Since the head disk itself has a sufficient moment of inertia, there is no need to provide a flywheel as a separate component. Therefore, the number of parts is small, and one of the conventional two ball bearings is replaced with a magnet, so material costs and assembly costs are reduced. Furthermore, since the number of rolling bearings is reduced, resistance to driving the head disk is small, and the drive motor can be made smaller.

Furthermore, since the head disk is directly supported by the cylinder body without the use of a shaft, assembly accuracy is high.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the VTR cylinder according to the present invention.
FIG. 2 is a cross-sectional view of a conventional VTR cylinder. 1a, 1b...Magnet, 2...Upper cylinder, 3
...Lower cylinder, 4...Rolling bearing, 8...
Head disk, 30... shaft portion, 83... head disk scrim body, 84... head disk body.

Claims (1)

[Scope of utility model registration request] A head disk 8 is housed inside a cylinder body 9 formed by fixing the upper cylinder 2 and the lower cylinder 3 to each other, and the head disk is rotated.
In the VTR cylinder, a cylindrical shaft portion 30 is provided in the center of the internal space formed by the upper cylinder 2 and the lower cylinder 3, and the inner ring 4a of the rolling bearing 4 is fitted into the shaft portion and fixed. The outer ring 4b of the rolling bearing 4 is fitted with a head disk 8 to rotatably support the head disk 8 to the shaft portion 30, and the head disk 8 has a substantially disk-shaped main body 84 and a main body A rim body 83 is provided that protrudes along the outer circumferential edge, and a pair of magnets 1a and 1b that repel each other are arranged concentrically with the cylinder shaft portion 30 between the outer circumferential surface of the rim body 83 and the inner circumferential surface of the cylinder body. A video tape recorder characterized in that one magnet is fixed to the rim body 83 of the head disk, and the other magnet is fixed to the cylinder body, so that their repelling surfaces face each other with a slight gap. cylinder.