JPH0676251A - Rotary drum for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize space saving and a low cost in a device by reducing the number of parts in a damper unit suppressing resonance in the rotational direction of a rotary drum for a VTR and reducing the weight. CONSTITUTION:A rotor case 13a constituting of a rotor unit 13 is attached to an end ring 11 being a bearing pressing member through an elastic body 16. Otherwise, the elastic body is held between the rotor case 13a and a rotor magnet 13b. Further, the rotor case 13a is attached to a rotor unit supporting member being the other body as the end ring 11 through the elastic body. Thus, without providing the elastic supporting plate and a balancer in addition, the damper unit is constituted by the end ring 11, the elastic body 16 and the rotor unit 13, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drum of a magnetic recording / reproducing apparatus (hereinafter referred to as VTR).

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing the structure of a conventional VTR rotary drum. In the figure, 1 is a rotation axis,
A flange 2 is integrated with the upper portion of the rotary shaft 1, and an upper drum 3 is attached to the upper surface of the flange 2 with screws 4. A rotary rotary transformer 5 is fixed to the upper drum 3 around the flange 2 by adhesion or the like, and a magnetic head 6 is screwed to the lower surface on the outer peripheral side.
Further, bearings 7 and 8 are attached to the rotary shaft 1 at a position in contact with the lower end of the flange 2 and at a position below the flange 2 and separated by a predetermined distance, and the lower drum 9 is press-fitted into the outer of these bearings 7 and 8. The fixed-side rotary transformer 10 is fixed to the lower drum 9 by adhesion or the like. Further, an end ring 11 for preloading the bearings 7 and 8 is fixed to the lower part of the rotary shaft 1 by screws 12. Then, the rotor case 13a is attached to the lower surface of the end ring 11 by the screw 14,
A rotor magnet 13b is fixed to the upper surface of 3a by adhesion or the like, and the rotor case 13a and the rotor magnet 13b constitute a rotor unit 13.
Further, an elastic support plate 15 is attached to the lower surface of the rotor case 13a by tightening together with the screws 14, and the balancer 1 is attached to the lower surface of the elastic support plate 15 via an elastic body 16.
7 is attached. Reference numeral 18 is a motor stator fixed to the lower drum 9 side by screwing or the like.

In the above structure, when a current is passed through the motor stator 18, the rotor unit 13 rotates and the rotating shaft 1
Torque is transmitted to the upper drum 4 via the magnetic head 6
Rotates.

As shown in FIG. 5, the structure of the rotary drum is such that rotary members are attached above and below a rotary shaft, and a damper unit is added to the rotary members via elastic members. Here, the upper rotating body is composed of the flange 2, the upper drum 3, the rotary transformer 5, and the magnetic head 6, and the lower rotating body is composed of the end ring 11 and the rotor unit 13. Resonance occurs in the rotation direction when applied as an exciting force, and the resonance frequency f in that case is expressed by the following equation.

[0005]

[Equation 1] That is, the resonance frequency f is proportional to the moments of inertia I ₁ and I ₂ , and inversely proportional to the effective shaft length. Then, due to this resonance, the reproduction screen is bent. Therefore, in order to eliminate this bending, the damper unit is added as described above. The damper unit comprises an elastic support plate 15, an elastic body 16 and a balancer 17,
It has a predetermined moment of inertia I ₃ , which suppresses the resonance in the rotational direction, that is, the torsional resonance.

[0006]

In the conventional rotary drum for a VTR, a damper unit is constructed by attaching a balancer to the rotating body via an elastic support plate and an elastic body in order to suppress resonance in the rotating direction as described above. However, there are problems that the number of parts is large, the cost is high, the weight is large, and the space is required.

The present invention has been made in order to solve such a problem, and it is possible to reduce the number of parts of the damper unit, reduce the weight, save the space and reduce the cost. It is intended to be provided.

[0008]

A rotary drum of a magnetic recording / reproducing apparatus according to the present invention is composed of a first rotary member including an upper drum having a magnetic head and a rotor unit on a motor rotating side. And a second rotating body that is disposed above and below the lower drum, and a rotating shaft that transmits torque from the second rotating body to the first rotating body is provided. The rotating shaft is connected to the lower drum via a bearing. In a rotating drum of a supported magnetic recording / reproducing apparatus, at least a part of a second rotating body is attached to the rotating shaft via an elastic body, and a rotor unit, an elastic body and the like are integrated to form a damper unit. It was done like this.

[0009]

According to the present invention, since the rotor unit is integrated with the elastic body and the like to form the damper unit, resonance in the rotational direction, which causes screen bending, is suppressed, and the number of parts is reduced and the weight is reduced. Space saving and cost reduction are achieved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1. First Embodiment FIG. 1 is a sectional view showing the structure of a rotary drum according to a first embodiment of the present invention. In this example,
The rotor case 13 a is attached to the end ring 11 via the elastic body 16. In this case, the bearings 7 and 8 are preloaded by integrally mounting the end ring 11, the elastic body 16, the rotor case 1a and the rotor magnet 13b on the rotary shaft 1. The other points are shown in Fig. 4.
Since it is the same as the conventional device shown in FIG.

In the case of the first embodiment, the end ring 11 also has the function of the elastic supporting plate 15 in the conventional apparatus of FIG.
Since the rotor unit 13 (the rotor case 13a and the rotor magnet 13b) also has the function of the balancer 17 and the damper unit is constituted by the end ring 11, the elastic body 16 and the rotor unit 13, the above-mentioned elastic support plate which has been conventionally required. 15 and balancer 1
7 becomes unnecessary. The resonance reduction effect of the damper unit in this embodiment is equivalent to that of the conventional one.

Example 2. Second Embodiment FIG. 2 is a sectional view showing the structure of a rotary drum according to a second embodiment of the present invention. In this example,
An elastic body 16 is provided between the rotor case 13a and the rotor magnet 13b. In this case, the bearings 7 and 8 are preloaded by integrally mounting the end ring 11, the rotor case 1a, the elastic body 16 and the rotor magnet 13b on the rotary shaft 1. Since the other points of this embodiment are the same as those of the conventional apparatus shown in FIG. 4, the same reference numerals are used in the drawing and the description thereof is omitted.

In the case of the second embodiment, the rotor case 13a
4 also functions as the elastic support plate 15 in the conventional apparatus of FIG. 4, the rotor magnet 13b also functions as the balancer 17, and the rotor unit 13a, the elastic body 16 and the rotor magnet 13b constitute a damper unit. As in the case of Example 1, the elastic support plate 15 and the balancer 17, which have been conventionally required, are no longer required,
Moreover, the resonance reducing effect of the damper unit can be made equal to that of the conventional one.

Example 3. Third Embodiment FIG. 3 is a sectional view showing the structure of a rotary drum according to a third embodiment of the present invention. In this example,
A rotor unit support member 19 that is separate from the end ring 11 that is a bearing preload member is provided, the rotor case 13a is attached to the rotor unit support member 19 via the elastic body 16, and the rotor unit is supported by the screw 20 on the rotary shaft 1. The member 19 is fixed. In this case, the rotor unit 13 can be mounted after preloading the bearings 7, 8 by the end ring 11. Since the other points of this embodiment are the same as those of the conventional apparatus shown in FIG. 4, the same reference numerals are used in the drawing and the description thereof is omitted.

In the case of the third embodiment, the rotor unit supporting member 19 also has the function of the elastic supporting plate 15 in the conventional apparatus shown in FIG. 4, and the rotor unit 13 (the rotor case 13a and the rotor magnet 13b) is also the balancer 17.
Since the damper unit is composed of the rotor unit 13, the elastic body 16, and the rotor unit supporting member 19 and also has the above-described function, the elastic supporting plate 15 and the balancer 17 which are conventionally required are not required as in the first embodiment. Moreover, the resonance reducing effect of the damper unit is equivalent to that of the conventional one.

[0017]

As described above, according to the present invention, since the rotor unit is integrated with the elastic body or the like to form the damper unit, the effect of suppressing resonance in the rotational direction which causes the screen bending is obtained. Can reduce the number of parts, reduce the weight, and save space and cost while maintaining the same level as before.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a rotary drum according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a rotary drum according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing the structure of a rotary drum according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing the structure of a conventional VTR rotary drum.

FIG. 5 is an explanatory diagram of a vibration system of this type of rotary drum.

[Explanation of symbols]

 1 rotating shaft 3 upper drum 6 magnetic head 7 bearing 8 bearing 9 lower drum 13 rotor unit 16 elastic body 19 rotor unit supporting member

Claims (1)

[Claims] 1. A first rotating body composed of an upper drum or the like having a magnetic head and a second rotating body composed of a rotor unit on the motor rotation side are arranged above and below a lower drum. In a rotary drum of a magnetic recording / reproducing apparatus, a rotary shaft for transmitting torque from the second rotary body to the first rotary body is provided, and the rotary shaft is supported by the lower drum via a bearing, A rotary drum of a magnetic recording / reproducing apparatus, wherein at least a part of the second rotary body is attached to the rotary shaft via an elastic body.