JPH0491653A - Rotary cylinder device - Google Patents

Abstract

PURPOSE:To enable the number of parts and assembly man-hour to be reduced by using a back yoke as a dynamic damper for moving or attenuating a resonant point of a rotary axis. CONSTITUTION:A back yoke 11 is supported to a boss 7 through an elastic material layer 14 such as rubber for achieving degree of freedom which is different from a back plate 9 which is fixed by a rigid member. Therefore, an upper drum 5 and a motor part 2 move and attenuate a resonant point as a vibration model of a system of two degrees of freedom for preventing inferior influence such as jitter, thus eliminating the need for providing a dynamic damper and enabling the number of parts and assembly man-hour to be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a rotating cylinder device that can be used in a magnetic recording/reproducing device, and is particularly characterized by means for reducing and eliminating resonance vibrations of the rotating cylinder.

BACKGROUND OF THE INVENTION In recent years, it has been desired that rotary cylinder devices have higher performance. An example of the above-mentioned conventional rotary cylinder device will be described below with reference to the drawings.

In FIG. 3, 1 is a cylindrical lower drum, and a rotating shaft 3 is rotatably supported at the center of the drum by a bearing 2. In FIG. At the tip of the rotating shaft 3, there is a magnetic head 4.
A cylindrical upper drum 5 to which is fixed is fixed via a first boss 6.

A second boss 7 is fixed to the other end of the rotating shaft 3, and a back plate 9 supporting an annular rotor magnet 8 is fixed to the second boss 7.

Reference numeral 10 designates the rotary shaft 3 on the fixed part (lower drum 1 side) so as to face the rotor magnet 8 with a predetermined interval.
The stator coil is arranged in an annular shape around the center.

Reference numeral 11 denotes a back yoke fixed to the second boss 7 so as to face the rotor magnet 8 via the stator coil 10, and receives magnetic flux from the rotor magnet 8 to transfer the magnetic flux from the rotor magnet 8 to the back yoke 11-.
A magnetic loop of the second boss 7 and the rotor magnet 8 is formed.

That is, the rotor magnet 8, the stator coil 1
0. The hack yoke 11 constitutes a motor that rotationally drives the rotating shaft 3.

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

The upper drum 5 is rotationally driven by the motor having the above-described configuration, and records and reproduces signals on a magnetic tape (not shown) guided by the lower tram 1 by the magnetic head 4.

At this time, in the above configuration, the upper tram 5 and the rotor magnet 8 are attached to both ends of the rotating shaft 3, which is small but has elasticity.
is located, causing resonant vibration in a one-degree-of-freedom system. In order to solve this problem, a disk 12 made of a metal plate is fixed to the hack plate 9 via an elastic member 13 made of rubber or the like, so that the resonance point can be moved and converted into a two-degree-of-freedom vibration model. The structure is designed to prevent negative effects such as jitter.

Problems to be Solved by the Invention However, the above configuration has the problem that it is necessary to provide a disk 12 that serves as a dynamic damper just for moving and damping the resonance point, and the number of parts increases. was.

In view of the above-mentioned problems, the present invention provides a rotating cylinder device that reduces the number of parts and the number of assembly steps.

Means for Solving the Problems In order to solve the above problems, the rotating cylinder device of the present invention includes a rotary shaft supported rotatably, a stator coil arranged annularly around the rotary shaft, and a stator coil arranged in a ring around the rotary shaft. a permanent magnet disposed opposite to the stator coil for generating magnetic flux linking with the stator coil to obtain rotational driving force of the motor; and a first rotating shaft fixed to the rotating shaft for holding the permanent magnet. and a second rotating body made of a magnetic material that is arranged to face the permanent magnet via the stator and receives the magnetic flux generated from the permanent magnet and forms a magnetic loop.
a second rotating body between the first rotating body and the second rotating body;
The rotating body is elastically fixed to the first rotating body by an elastic member.

Effects According to the above configuration, the hack yoke, which is necessary for achieving the same characteristics as the motor, is used as a dynamic damper that moves and damps the resonance point of the rotating shaft, so a specially added dynamic damper is not required. This makes it possible to reduce the number of parts and assembly man-hours.

Example Below, regarding a rotating cylinder device according to an example of the present invention,
This will be explained with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of the essential parts thereof. In FIGS. 1 and 2, the same components as those in the conventional example shown in FIG. 3 are given the same reference numerals.

The difference between this embodiment and the conventional example is that in this embodiment, the back yoke 11 is supported on the second boss 7 via an elastic material layer 14 such as rubber, and the disc 12 is removed. .

In the rotary cylinder device configured in this way,
When the upper tram 5 rotates, the back yoke 11
4 through the second rotor boss 7 (: fixed, it has a different degree of freedom system from the back plate 9 which is fixed with a rigid member. Therefore, the upper drum 5 and the motor part have two degrees of freedom) As a frequency-based vibration model, it moves and damps the resonance point to prevent negative effects such as jitter.

Effects of the Invention As described above, according to the present invention, there is no need to provide a dynamic damper, which was conventionally provided only for moving and damping the resonance point, and the number of parts and assembly man-hours can be reduced, resulting in cost reduction. Excellent effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotary cylinder device according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of FIG. 1, and FIG. 3 is a sectional view of a conventional rotary cylinder device. 1... lower drum, 2... hair ring,
3...rotating shaft, 5...upper drum, 6,
7...Boss, 8...Rotor magnet, 9...Hack plate, 10...Stator coil, 11...Hack yoke, 13.
...Elastic material layer. Name of agent Patent attorney Shigetaka Awano 1 person Fig. / /4 f / Lower tram hair non-k rotation shaft 1F ram 7-boss roku mag λsoT ノ (Sokufu 2 rate stator coil I)

Claims (1)

[Claims] A rotary shaft supported rotatably, a stator coil arranged annularly around the rotary shaft, and a magnetic flux arranged opposite to the stator that interlinks with the stator coil to generate the rotational driving force of the motor. a first permanent magnet fixed to the rotating shaft to hold the permanent magnet;
a second rotating body made of a magnetic material that is arranged to face the permanent magnet via the stator and forms a magnetic loop that receives the magnetic flux generated from the permanent magnet; and the first rotating body. A rotary cylinder device comprising: an elastic member disposed between the second rotating body and elastically fixing the second rotating body to the first rotating body.