JPS5893459A - Dc motor for driving capstan - Google Patents

Abstract

PURPOSE:To reduce the entire thickness of a motor by employing as a bearing the inner periphery of a rotational shaft and composing the bearing member of a combination of a supporting shaft and the shaft. CONSTITUTION:A rotational shaft 2 of hollow cylindrical shape is rotatably engaged with a supporting shaft 1. A circular yoke 6 is fixed through a yoke holder 7 to a rotational shaft 2, and an armature coil 9 is fixed through a dust core 8 in the yoke 6. A cylindrical commutator 10 is fixed to the lower end of the shaft 2, the end of the armature coil is connected, and is rotated integrally with the shaft 2. The commutator 10 is slidably elastically contacted by a brush 11 which is fixed to the housing 4, and a flat stator magnet 12 is fixed to the housing 4. With this structure, the periphery of the shaft 2 becomes a bearing, and the bearing member is only a combination of the shaft 1 and 2, thereby reducing th entire thickness of a motor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct current motor for directly driving a capstan with a novel bearing structure.

Conventionally, in a cassette recorder/player, a system has been adopted in which the reel or capstan is directly driven in order to avoid complicating the drive of the reel and capstan using movable members such as belts and idlers.

However, even in the direct drive method, it is complicated to reduce the thickness of the capstan motor to a desired size because of restrictions on bearing dimensions.

In view of the above-mentioned problems, the present invention enables direct driving of a capstan with a simple configuration, and can be provided at a low cost because it uses a motor with a commutator and eliminates a field position detection element.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

In the figures, the same reference numerals indicate the same members or the same functions.

FIG. 1 (,) shows a sectional view of an embodiment according to the invention.

A casing 4 made of magnetic material is pressed into a concave shape as shown, and a support member 5 into which a support shaft 1 is press-fitted in the center of the recess is fixed to the casing 4 by means such as caulking.

A hollow cylindrical rotary shaft 2 is rotatably fitted into the support shaft 1, and the upper portion of the rotary shaft 2 in the longitudinal direction serves as a thrust receiving portion. The longitudinally upper part is formed into a hemispherical shape so as to receive and hold the steel ball 3 which is bent, and the diameter of the hole 3-11 at the uppermost end is smaller than the diameter of the steel ball 3.

The hole 13-1 is provided for the purpose of easily fitting the rotating shaft 2 into the support shaft 1, and the rotating shaft 2 is inserted into the hole 3-1.
Even if it has a cylindrical shape with a bottom, it is not particularly necessary if the above-mentioned insertion is not made difficult by residual air.

A circular yoke 6 is fixed to the rotating shaft 2 via a yoke holder 7. Here, the rotating shaft 2 and the yoke holder 7 are press-fitted. The outer periphery of the yoke 6 is bent downward to form a cup shape, and an armature winding 9 is fixed within the yoke 6 via a powdered iron core 8. The details of the electric machine pre-winding #9 are fan-shaped as shown in FIG. 1(b), and the effective conductor portion 9-1.9- contributes to torque generation.
2 and the invalid part 9-3゜9 which does not generate torque in principle
-4.

A cylindrical commutator 10 is fixed to the lower end of the rotating shaft 2 and connected to the terminals of the armature winding, so that the commutator 10 rotates together with the rotating shaft 2.

The cylindrical commutator 10 has a brush 11 fixed to the housing 4.
It is slidably and elastically contacted by. In addition, the housing 4
The i
A flat stator magnet 12 is fixed.

With the above-mentioned configuration, the inner periphery of the rotary shaft 2 is a bearing, and the only bearing member is the combination of the support shaft 1 and the rotary shaft 2, so that the entire electric motor can be made completely thin.

In addition, after the magnetic flux of the stator magnet 12 passes through the armature winding 9, it does not reach the yoke 6, but instead exists along the magnetic circuit closed by the powdered iron core, so that hysteresis loss and eddy current loss during rotation are reduced. The electric motor has good efficiency.

Further, in order to improve the efficiency, the shape of the armature winding shown in FIG. 1(b) is changed and the ineffective portion is bent, which will be described with reference to the embodiment shown in FIG.

As shown in FIG. 2(b), the fan-shaped wax machine winding a13 is composed of an effective conductor portion 13-1, 13-2 and an ineffective portion 13-3, 13-4 that contribute to torque generation.
Of these, the longest arc part of the sector (invalid part 13-4)? It is bent approximately at right angles to the plane formed by the other three parts.

The state in which the armature winding 13 is assembled into the motor is shown in Figure 2 (
, ).

As in the embodiment shown in FIG. 1, a rotary shaft 3 having a yoke 6 fixed thereto is fitted onto a support shaft 1 set up in the center of a concave housing 4, and a powder iron core is inserted into the yoke 6. 8, the armature winding 13 is connected to the ineffective portion 13-4, which is a bent portion as shown in the figure.
is arranged with the bent portion facing the stator magnet 12 side.

If the above arrangement is used, most of the magnetic flux of the stator magnet 12 will pass through the effective conductor portion of the armature winding.
This increases the effect of contributing to torque generation.

The above is the configuration of the embodiment according to the present invention.According to the present invention, the conventional method which is not a direct drive method has the first belt between the motor and the seven fly wheels, and the first belt between the flywheel and the reel drive mechanism. 2 belts were required in total, but it is clear that the latter second belt can drive the capster/reel stand, which reduces the number of worn parts and is inexpensive. This makes it possible to provide a simple cassette recorder/player.

[Brief explanation of the drawing]

FIGS. 1(a) and 2(,) are sectional views of an embodiment according to the present invention, and FIGS. 1(b) and 2(b) are views showing the shape of the armature winding, respectively. DESCRIPTION OF SYMBOLS 1... Support shaft, 2... Rotating shaft %, 3... Steel ball, 4... Housing, 5... Support member, 6...
...Yoke, 7...Yoke holder, 8...
・Powder iron core, 9.13... Armature winding, 10・
...Commutator, 11...Brush, 12...Stator magnet. Patent Applicant'f:,/Ku (I) q ('J)

Claims (3)

[Claims] (1) A support shaft installed in a magnetic housing, a fully cylindrical rotation shaft rotatably fitted into the support shaft, and a circular yoke that rotates together with the rotation shaft. , a plurality of armature windings fixed in the circular yoke, a commutator to which terminals of the armature windings are connected and fixed to the rotating shaft, and a commutator fixed to the housing, N, S. A capstan drive characterized in that it is composed of an annular and flat stator magnet that is magnetized with multiple poles alternately, and a brush provided on the housing that is in contact with the commutator 4'2Jl and supplies power. DC motor for use. (2) The DC motor for driving a capstan according to item (1) of the patent, characterized in that a powdered iron core is interposed between the circular yoke and the armature winding. (3) One end of the rotating shaft in the longitudinal direction is formed into a hollow hemispherical shape with a hole, and a steel ball is placed on one end of the support shaft into which the rotating shaft is inserted. Capstar/drive DC motor described in item 1).