JPH01186146A - Capstan motor - Google Patents

Abstract

PURPOSE:To obtain a stable shaft output by interposing a clamping ring between a rotor core metal and a rotary shaft, thereby eliminating the eccentricity of a rotor. CONSTITUTION:A clamping ring 20 for rigidly coupling the rotor core metal 30 of a capstan motor and a rotary shaft 4 is interposed between both without generating the eccentricity of a rotor 8. The metal 30 to be mounted with the ring 20 is formed with female threads to be engaged with male threads 21 on the inner periphery of a body 31, with a space to be inserted with the clamping part of the ring 20, and formed with an inner periphery having the same or slightly sharper slope than the inclining angle of the tapered part of the ring 20.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a capstan motor, and more particularly,
This invention relates to a capstan motor that directly transports a tape in a magnetic recording/reproducing device or the like using a motor shaft.

(b) Prior Art FIG. 5 is a partially cutaway side view of a conventional capstan motor. In the figure, bearings 2 and 3 are disposed near one end and the other end inside a housing 1, and the pair of bearings 2 and 3 have a rotating shaft made of a non-magnetic material such as stainless steel. One end of the 0-rotation shaft 4 (the left end in the figure) on which the 0-rotation shaft 4 is pivotally supported extends so as to protrude from the housing 1, and the other end (the right end in the figure) of the 0-rotation shaft 4 constituting the capstan shaft. ) is fitted and fixed with a pulley 5 for a double capstan, and adjacent to this pulley 5, a rotor core metal 6 is fixed to the rotating shaft 4. The rotor core metal 6 is attached to the rotating shaft 4 with a screw (not shown) screwed into a stopper hole 7.

A disk-shaped rotor 8 is integrally attached to the rotor core metal 6. This rotor 8 has a coil formed on an insulating substrate by a method such as photoetching, and is equipped with sliding contacts for switching and supplying external power according to rotation. Magnets 9 are fixedly installed on the housing leg 1 side facing the rotor 8 on both sides thereof at predetermined intervals in the circumferential direction and with the polarities alternately reversed. This magnet 9 becomes a stator. The brush 1 is slidably connected to the sliding contact provided near the rotor core 6 of the rotor 8.
0 is arranged and held in the brush holder 11. Note that 12 is a bearing housing. Further, 13 is an encoder unit that outputs a position signal for controlling rotation, and 14 is a bolt mounting hole for fixing to a recording/reproducing device or the like.

In the above configuration, when DC power is supplied to the pair of brushes 10, a magnetic field is generated by the current flowing through the printed coil of the rotor 8, which generates a repulsive force against the magnet 9, which causes the rotor 8 to have rotational torque. Grant. By sequentially forming a magnetic field in the plurality of printed coils, the rotor 8 rotates continuously, and the rotating shaft 4 rotates accordingly.

At the same time, a pulse signal corresponding to the rotation speed is sent from the encoder unit 13, and this signal is used as information for rotation control.A magnetic recording medium (magnetic tape) is attached to the capstan shaft portion of the 0-rotation shaft 4 in a pinch (not shown). It is pressed into contact with rollers and is transferred depending on the rotational state of the rotating shaft 4.

In this type of capstan motor, before the rotor 8 is assembled into the housing 1, the brush 10 is generally cleaned by removing cutting waste from the groove of the rotor 8, chamfering, surface polishing, cleaning, etc.
Preliminary work has been carried out to ensure smooth sliding contact.

However, in the capstan motor configured in this way, when the pulley 5 is attached to the other end,
Since it is not possible to fix the rotor core 6 with a retaining metal fitting or the like, the only option is to screw the rotor core 6 through the stopper hole 7. , the characteristics of each motor will be different. That is, (a) there is a difference in the coefficient of linear expansion of each member, which causes an unstable element due to the temperature factor; (b) the resonance point of the motor itself changes (for example, 3.
(7KHz), unnecessary resonance occurs due to the motor drive frequency, which creates a beat condition with the FM carrier and adversely affects the signal recorded on the tape. (c) PLL (Phase Locke)
d Loop), etc., when rotating the motor with servo,
Since the rotor is not firmly fixed to the rotating shaft, changes in the vibration energy of the magnetic circuit are not stable, and as a result, the required stability cannot be obtained.

Due to these causes, when a motor is incorporated into a magnetic recording/reproducing device and selectively rotated from low speed to high speed, there is a problem that desired characteristics cannot be obtained. In particular, this problem extremely deteriorates the S/N ratio in magnetic recording and reproduction when the tape is transported at a low speed.

(Q) Purpose The present invention was made in view of the above-mentioned circumstances, and its purpose is to assemble the motor shaft and the rotor core metal with high precision without reducing the tolerances of the shaft and the rotor core very much. To provide a capstan motor that can reduce adjustment man-hours, ensure long-term stability including temperature changes and changes over time, and improve responsiveness and S/N ratio. It is in.

(d) Structure In order to achieve the above object, the present invention provides a capstan motor in which the rotating shaft of the rotor is extended and used directly as a capstan, and the rotor is fixed to the rotating shaft via a core metal. Screwed onto the rotor core metal, at least one slit is provided at the tip end on the screwing side,
The present invention is characterized in that a tightening ring is provided that presses the inner periphery of the tip portion against the rotating shaft depending on the screwing amount.

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

FIG. 1 is a cross-sectional view showing the configuration of essential parts of an embodiment of a capstan motor according to the present invention. In this embodiment, the same parts as in the conventional example shown in FIG. 5 are given the same reference numerals. The explanation thereof will be omitted, and the different configurations will be explained.

The features of this embodiment include, in addition to the above conventional example,
This is because a tightening ring 20 is provided. As shown in FIGS. 2 to 4, the tightening ring 20 has a male threaded portion 21 screwed into a female threaded portion provided on a rotor core metal 30 having a space into which the tightening ring 20 is inserted, and a bent tip. A mounting portion consisting of a slotted recess 22 into which a bifurcated driver-like tool is inserted, a tapered portion 23 that projects from the male threaded portion 21 and whose outer diameter decreases toward the tip, and a tapered portion 23 provided on the tapered portion 23. (four in this example)
and a tightening portion consisting of a slit 24. A through hole 25 having a diameter slightly larger than the diameter of the rotating shaft 4 is formed in the center of the mounting portion and the tightening portion.

The rotor core metal 30 to which this tightening ring 20 is attached has a female thread formed on the inner periphery of the body 31 to engage with the male threaded section 21, and a space for inserting the tightening section of the tightening ring 20. The inner periphery of the tapered portion 23 is machined to have an inclined inner surface with the same or slightly acute angle as the inclined angle of the tapered portion 23.

In the above configuration, when assembling it, the bearings 2 and 3, the encoder output shaft 13, and the left side part of the magnet 9 are attached to the housing 1 shown in FIG. Insert the rotated shaft 4.

Next, the tightening ring 2o shown in FIGS. 2 to 4 is lightly screwed into the rotor core 30 to which the rotor 8 is fixed, and the rotor core 30 is fitted onto the rotating shaft 4 in this state, so that the rotor 8 is fixed. It is moved to the back side (to the left side in FIG. 1) with respect to the magnet 9 until a predetermined gap is reached. When the tightening ring 2° is gradually tightened while holding this position, since the tapered portion 23 is provided with the slot 24, the tapered portion 23 is pressed against the inclined inner surface of the rotor core metal 30, which has high rigidity. The rotor core metal 30 is firmly fixed to the rotating shaft 4 without being eccentric.

As a result, the variation in processing accuracy that occurs when simply fitting and the coefficient of linear expansion (in the case of die casting, 22 x 10")
In the case of stainless steel, it is possible to absorb temperature changes in characteristics caused by a difference of 16 x 10-'').

In addition, when a servo system is configured by feeding back the encoder output as a sensor, the rigidity of the capstan motor increases, the response can be improved, and PLL control can be performed with high precision, resulting in stable rotation accuracy. (speed control with less flutter component) can be obtained as the shaft output of the capstan shaft. Therefore, when used in a magnetic recording/reproducing device, stable tape running is possible.

It should be noted that the present invention is not limited to the above-described embodiments, but can be modified in various ways without departing from the spirit thereof. For example, it is also possible to configure the fitting portion of the rotor core metal 30 and the tightening ring 20 in the opposite manner. That is, the rotor core metal 30 is formed into a protruding shape, the tightening ring 20 is formed into a tapered hole shape that fits therein, a male thread is formed on the outer periphery of the body 31, and the tightening ring 20 is attached to the male thread from the outside. Just screw it on.

(e) Effects As explained in detail above, according to the present invention, in a capstan motor, a tightening ring is interposed between the rotor core metal and the rotating shaft to firmly connect the two without causing eccentricity of the rotor. As a result, assembly is possible even if the finishing tolerances of the rotating shaft diameter, rotor core hole diameter, rotor hole diameter, etc. are large to some extent, and the rigidity of the capstan motor is increased, and the response of the servo system is improved and stable. The shaft output can be obtained as follows.

Furthermore, according to the present invention, the number of adjustment steps is drastically reduced, temperature changes and changes over time are reduced, stable performance is obtained over a long period of time, and changes in the force acting between the rotor and the magnet, that is, the vibration energy, are stabilized. Therefore, the output torque is stabilized and the characteristics of the motor with small motor inertia can be maximized, and a good S/N ratio can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main structure of an embodiment of the present invention;
Figures 2, 3, and 4 are a rear view, left side view, and front view showing details of the tightening ring shown in Figure 1, respectively, and Figure 5 shows a part of a conventional capstan motor. It is a side view which shows it broken. 1...Housing, 2,3...
Bearing, 4...Rotating shaft, 8...
...Rotor, 9...Magnet, 2
0...Tightening ring, 21...Male threaded portion, 22...Concave portion, 23...Tapered portion, 24...Slot, 25...
Through hole, 30... Rotor core metal.

Claims (1)

[Claims] (1) In a capstan motor in which the rotating shaft of the rotor is extended and used directly as a capstan, and the rotor is fixed to the rotating shaft via a rotor core metal, the screw side is screwed to the rotor core metal and is used as a capstan. A capstan motor, characterized in that at least one slot is provided at the tip of the capstan motor, and a tightening ring is provided for pressing the inner periphery of the tip against the rotating shaft depending on the screwing amount of the slot.