JPH10269501A - Rotary drum device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary drum device improving corrective precision when rotation unbalance is corrected without deteriorating shape precision of an upper drum and also provided with a mark of an angular phase with respect to the rotary drum device. SOLUTION: This device is provided with a drum motor 6 provided with an upper drum driving motor rotor magnet 6a, an upper drum driving motor stator coil and a rotary yoke on a rotary upper drum having a rotary magnetic recording head, a fixed lower drum 5 having a step part guiding a magnetic recording tape, a fixed shaft 10 stuck to the fixed lower drum 5 and a rotary transformer stuck to the fixed lower drum 5. In such a case, the device is constituted so that a rotary yoke outer peripheral circular part is provided with the step between with the inner peripheral part, and this step rise part 20 is a size nearly smaller than an upper drum inner peripheral inner diameter, and is fitted to an upper drum opening part inner peripheral inner diameter, and a rotary yoke outer peripheral circular part edge 21 is in pressurizedcontact by an upper drum outer peripheral upper end part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small rotating magnetic head drum device such as a video movie having a rotating magnetic head drum, and more particularly to a method of fixing a rotating yoke of a motor for driving an upper drum and a shape of the yoke.

[0002]

2. Description of the Related Art A typical drum structure in a conventional rotary magnetic recording / reproducing apparatus will be described below with reference to FIG. The rotary magnetic head 1 is connected to a lead wire 2 connected to the rotary magnetic head 1 and a coil of the rotary transformer rotor 3, and the rotary transformer rotor 3 faces the rotary transformer stator 4 with a small gap. Then, the coil 4 of the rotary transformer stator 4
a is led out from the lower drum 5 and connected to a head amplifier circuit provided outside the drum. Then, an electric signal is transmitted and received between the rotating magnetic head 1 and the head amplifier circuit.

Next, an upper drum rotation drive motor 6 (hereinafter, referred to as an upper drum rotation drive motor 6)
) Will be described. The drum motor 6 is configured by disposing a motor driving rotor magnet (hereinafter referred to as a rotor magnet) 6a, a motor stator coil 6b, and a rotating yoke 6c on the upper drum. And the rotor magnet 6a
Are fixed to the upper drum 9 with screws 8 in the upper drum opening 7, and the motor stator coil 6 b is disposed on a flange member 11 fixed to a fixed shaft 10 erected on the lower drum 5. The rotating yoke 6c is disposed on the upper end step 9a.

[0004] Here, each part constituting the drum motor 6 will be described. The rotating yoke 6c is made of an iron-based material so that a magnetic flux generated from the rotor magnet 6a passes through the motor stator coil 6b effectively.
It is held by the attractive force of the rotor magnet 6a. The structure of the rotating drum or the drum motor as described above is employed particularly in a rotating magnetic recording / reproducing apparatus which is required to be small and thin.

On the rotating yoke 6c, a weight 12 for correcting rotational imbalance is provided at an unbalanced portion.
As shown in FIG. 7, this weight is stuck on the rotating yoke 6c by a method such as sticking with an adhesive tape 12a provided on the back surface, or bonding with an adhesive.

[0006]

However, as shown in FIG. 6, the upper end step 9a of the upper drum 9 is formed by lathe processing.
It is formed by further cutting the originally thin part. As a result, deformation due to processing is easily excited, which causes deterioration in the shape accuracy of the upper drum outer peripheral portion 9b, for example, cylindricity, and also leads to an increase in the processing time of the upper drum, which also increases the manufacturing cost. I have.

The weight 12 for correcting rotation imbalance is
In order to stably fix the rotary yoke 6c to a flat surface, the rotary yoke 6c has a planar shape as shown in FIG. For this reason, it is difficult to determine the position of the center of gravity of the weight, and since there is no mark indicating the angular phase on the rotating yoke 6c, it is difficult to accurately fix the weight to the unbalanced position specified by the rotation unbalance correcting device. This causes problems such as large variations in accuracy among workers.

In order to solve the above-mentioned problems, a rotary drum device provided with a mark of an angle phase without increasing the accuracy of the shape of the upper drum and improving the correction accuracy at the time of correcting rotational unbalance. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided a rotary drum device comprising: a rotary upper drum having a rotary magnetic recording head; Upper drum drive motor A drum motor provided with a stator coil and a rotating yoke, a fixed lower drum having a step for guiding a magnetic recording tape, a fixed shaft fixed to the fixed lower drum, and fixed to the fixed lower drum And a rotary transformer having a rotary transformer, wherein the outer circumferential portion of the rotating yoke has a step with the inner circumferential portion, and the step rising portion has a diameter substantially smaller than the inner circumferential inner diameter of the upper drum, and the inner circumferential inner diameter of the upper drum opening. , And a rotary yoke outer peripheral circle edge is pressed against the upper end of the upper drum outer periphery.

According to a second aspect of the present invention, there is provided a rotary drum device, wherein an upper drum driving motor rotor magnet, an upper drum driving motor stator coil, and a rotating yoke are arranged on a rotating upper drum having a rotating magnetic recording head. Drum motor, a fixed lower drum having a step for guiding the magnetic recording tape, a fixed shaft fixed to the fixed lower drum,
A rotary transformer fixed to the fixed lower drum, the rotary drum device comprising: a plurality of convex pieces and convex portions having the same circumference from the rotary yoke to the lower drum, and a circumcircle of the convex pieces and convex portions. Part fits into the inner diameter of the upper drum opening,
The outer peripheral circle edge of the rotating yoke is pressed against the upper end of the upper drum outer periphery.

According to a third aspect of the present invention, there is provided the rotary drum device according to the second aspect, wherein a rotation imbalance correcting weight is disposed in a concave portion which is equally circumferentially disposed on the rotary yoke. It is characterized by the following. With this configuration, it is possible to stably install a spherical weight or the like whose center of gravity is relatively easy to understand, so that it is easy to correct the rotational imbalance and to obtain the mark of the angular phase. .

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a structural sectional view of a rotary drum device using a shaft-integrated bearing 13.
The shaft 10 is a fixed shaft laid on the lower drum 5. The upper drum drive motor 6 is disposed in the opening 7 in the upper part of the upper drum in the same manner as the conventional one in order to reduce the size and weight.

FIG. 2 shows an embodiment of the shape of the rotating yoke 6c according to the present invention. FIG. 2B is a cross-sectional view at the center of the rotating yoke shown in FIG. As shown in FIG. 2B, the step rising portion 20 of the rotating yoke has a diameter substantially smaller than the inner diameter of the upper drum, fits into the inner diameter 9c of the upper drum opening, and maintains substantially concentric. Further, the outer circumferential edge 21 of the rotating yoke is pressed against the upper end 9d of the upper drum by the attraction force of the rotor magnet 6a to perform positioning in the axial direction.

Another embodiment of the shape of the rotating yoke 6c is shown in FIGS. The cross-sectional views at the center of the rotating yoke shown in FIG. 3A and FIG.
FIG. 3B is an enlarged view of a main part of the cross-sectional view, and FIG. 3C and FIG. Each of them is subjected to so-called "half blanking" and "cut-and-raising" processes by press working. The convex piece and the convex portion from the rotary yoke 6c to the lower drum side, the respective circumscribed circles 22 fit into the inner diameter of the upper drum opening, and each surface 23 contacts the upper drum upper end 9d surface.

Next, a method of arranging the weight for correcting the rotational imbalance in the concave portion equally arranged in the circumference of the rotary yoke shown in FIGS. 3 and 4 will be described with reference to FIG. In the vicinity of the outer periphery of the rotating yoke 6c, the concave portions 14 are formed so as to be circumferentially equally arranged. The weight 15 for correcting rotation imbalance is shown in FIG.
As shown in (2), even if it is spherical, it can be easily fixed with an adhesive or the like because it is stably positioned by being dropped into the concave portion 14. Further, since the position of the rotation imbalance and the position of the center of gravity of the weight are easily adjusted, the variation in the correction is reduced.

Even if there is an imbalance at a position where the concave portion 14 is not present, it is possible to correct the imbalance by arranging weights having an appropriate mass calculated by vector in the concave portions on both sides thereof. The same effect as described above can also be obtained by providing an unbalance corrector having a certain specific gravity (for example, MBR-010 manufactured by Nippon Kayaku Co., Ltd., Three Bond 3084 manufactured by Three Bond Co., Ltd.) in the concave portion 14.

[0017]

According to the first aspect of the present invention,
Even without providing a step on the inner periphery of the upper drum, the rotation yoke can be fixed, and the accuracy of the shape of the upper drum can be maintained and improved.

According to the configuration of the second aspect of the present invention, in addition to the above-described effects, since the convex pieces and the concave parts are equally arranged in the same circumferential shape, the indication of the position of the rotation imbalance correcting weight is clear. Can be performed.

According to the third aspect of the present invention, in addition to the above-described effects, the use of a spherical weight to stably dispose the rotation imbalance correcting weight in the hole or the concave portion of the rotating yoke. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a structural sectional view of a rotary drum device using a shaft-integrated bearing 13;

FIG. 2 is a structural diagram showing an embodiment of a shape of a rotating yoke 6c.

FIG. 3 is a structural view showing an embodiment of a rotating yoke 6c shape having a convex portion.

FIG. 4 is a structural diagram showing an embodiment of a rotating yoke 6c having a convex piece.

FIG. 5 is a diagram illustrating a method of arranging a weight for correcting rotational imbalance.

FIG. 6 is a typical drum structure diagram in a conventional rotary magnetic recording / reproducing apparatus.

FIG. 7 is a schematic view of a conventional imbalance correcting weight.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head 2 Lead wire 3 Rotary transformer rotor 4 Rotary transformer stator 4a Coil 5 Lower drum 6 Drum motor 6a Rotor magnet 6b Motor stator coil 6c Rotation yoke 7 Upper drum opening 8 Screw 9 Upper drum 9a Upper drum upper end 9b Upper drum outer periphery Part 9c Upper drum inner circumference 9d Upper drum outer circumference upper end 10 Fixed shaft 11 Flange member 12 Weight 13 Shaft-integrated bearing 14 Depression 15 Rotation imbalance correction weight 20 Rotation yoke step rising part 21 Rotation yoke outer circumference circular part edge 22 Convex piece 23 and the circumscribed circles 23.

Claims (3)

[Claims] 1. A drum motor in which an upper drum driving motor rotor magnet, an upper drum driving motor stator coil and a rotating yoke are arranged on a rotating upper drum having a rotating magnetic recording head, and a step for guiding a magnetic recording tape. In the rotary drum device having a fixed lower drum having a portion, a fixed shaft fixed to the fixed lower drum, and a rotary transformer fixed to the fixed lower drum, the outer circumferential portion of the rotating yoke has a step with the inner circumferential portion. The step rising portion has a diameter substantially smaller than the inner diameter of the upper drum, fits into the inner diameter of the upper drum opening, and the outer circumferential edge of the rotating yoke is pressed against the upper end of the upper drum outer periphery. Rotary drum device. 2. A drum motor in which an upper drum driving motor rotor magnet, an upper drum driving motor stator coil and a rotating yoke are disposed on a rotating upper drum having a rotating magnetic recording head, and a step for guiding a magnetic recording tape. In a rotary drum device having a fixed lower drum having a portion, a fixed shaft fixed to the fixed lower drum, and a rotary transformer fixed to the fixed lower drum, the rotary drum device includes a plurality of rotary drums having the same circumferential shape from the rotary yoke to the lower drum. Having a convex piece and a convex portion,
A rotary drum device, wherein the convex piece and the circumscribed circle of the convex fit into the inner diameter of the upper drum opening, and the outer circumferential edge of the rotary yoke is pressed against the upper end of the upper drum outer circumference. 3. The rotary drum device according to claim 2, wherein a rotation imbalance correcting weight is disposed in a concave portion which is equally circumferentially disposed on the rotary yoke.