JPS60226051A - Flywheel device - Google Patents

Abstract

PURPOSE:To suppress the unevenness of rotation by applying disturbance torque and reverse phase braking force to the flywheel. CONSTITUTION:A pulse-like electric signal proportional to an angular velocity obtained from the output of a photocoupler 22 is converted into an analog voltage signal corresponding to the frequency by an F/V converter 23. The analog voltage signal is differentiated by a differential circuit 24, the differentiated result is added to bias voltage by an adding point 26 and the added signal is amplified by an amplifier 27 and then applied to a coil 21b of an electromagnetic braking device 21. If the angular velocity is reduced by the disturbance torque applied to the flywheel, the output of the F/V converter 23 is dropped and a negative signal is obtained from the output of the differential circuit 24. If the angular velocity of the flywheel 14 is increased by the disturbance torque on the contrary, current flowing into the coil 21b is increased, the braking force is increased and the angular velocity of the flywheel is reduced. Thus, the inertial moment of the flywheel can be increased equivalently and optionally in a limited space.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a flywheel device installed on a capstan shaft or the like that needs to be rotated at a constant speed in order to run a tape at a constant speed in a tape recorder. It is something.

[Technical background of the invention and its problems]

Conventionally, there has been a capstan device shown in Fig. GS5 for running a tape at a constant speed. In the figure, 2 is a capstan shaft supported by a bearing 3, 4 is a flywheel provided on the capstan shaft 2, and 5 is a hook that is passed between the rotary shaft of a motor (not shown) and the flywheel 4. This is a transmission belt that transmits the rotational torque of the flywheel 4 to the flywheel 4.

Now, the flywheel 4 is accelerated by applying the rotational torque T from the motor through the belt 5, and an arbitrary angular velocity Ω is applied to the capstan shaft 2. At this time, if the disturbance torque TL applied to the capstan shaft 2, the moment of inertia of the flywheel 4 is J, and the Laplace operator is S, these relationships are expressed by a block as shown in Figure 6, and the angular velocity Ω is as follows. It is expressed as the formula.

Ω - (T - T L) / S J As is clear from the above equation, in order to suppress the fluctuation of the angular velocity Ω with respect to the disturbance torque TL, it is sufficient to increase the moment of inertia J, but if the moment of inertia) J is increased In order to achieve this, it is necessary to increase the outer diameter (or thickness) of the flywheel 4, so if the dimensions are limited due to miniaturization of the mechanism, there is a limit to suppressing uneven rotation due to external disturbances. Ta.

[Purpose of the invention]

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional devices, and its purpose is to provide a flywheel device that can equivalently freely increase the moment of inertia of the flywheel in a limited space. There is.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, 11 is a motor, 12 is a capstan shaft supported by a bearing 13, 14 is a flywheel provided on the capstan shaft 12, and 15 is a rotating shaft 1 of the motor 11.
A belt is passed between 1a and the flywheel 14, and is a transmission belt that transmits the rotational torque of the motor 11 to the flywheel 14.

Reference numeral 20 denotes a disc made of a conductive material fixed to the flywheel 14, and on the outer periphery of one surface of the disc 20, as shown in FIG. 2, a light reflecting part 20a and a light absorbing part 20b are provided. formed alternately.

Reference numeral 21 denotes a U-shaped core 21a made of a magnetic material and the core 2.
This is an electromagnetic braking device consisting of a coil 21b wound around a core 21a, and the outer periphery of a disc 20 is located between opposing pieces of a core 21a, and a light reflecting part 20a and a light absorbing part 20b on the disc 20.
As shown in FIG. 3, a photocoupler 22 consisting of a light emitting diode 22a and a phototransistor 22b is provided at a portion facing the phototransistor 22b. Therefore, photocoupler 22
The output includes a disk 1 rotating together with the capstan shaft 12.
A pulsed electrical signal is obtained which has an H level and an L level at a period (frequency) corresponding to the angular velocity of 6.

23 is a frequency-voltage (F-V) converter that converts the frequency signal from the output of the photocoupler 22 into a voltage signal of a magnitude corresponding to the frequency; 24 is the voltage obtained at the output of the F-■ converter 23; 25 is a bias voltage generator; 26 is a summing point that adds the output of the differentiation circuit 24 and the bias voltage from the bias voltage generator 25; 27 is a drive amplifier that drives the electromagnetic braking device 21; be.

With the above configuration, a pulsed electrical signal proportional to the angular velocity obtained from the output of the photocoupler 22 is transmitted to the F-V converter 2.
3, it is converted into an analog voltage signal with a magnitude corresponding to its frequency. The output of this F--converter 23 is differentiated by a differentiating circuit 24, and the resulting value and the bias voltage are added at a summing point 26. The signal obtained at the output of the summing point 26 is amplified by an amplifier 27 and then applied to the coil 21b of the electromagnetic braking device 21.

Now, if the angular velocity of the flywheel 14 is reduced due to disturbance torque applied to the flywheel 14, the output of the F-V converter 23 will be reduced. Differentiating circuit 2 that differentiates the output of this converter 23
4, a negative signal whose magnitude corresponds to the magnitude of change in the output of the converter 23 is obtained.

Contrary to the above case, when the angular velocity of the flywheel 14 increases due to disturbance torque, the electromagnetic braking device 21
The current flowing through the coil 21b increases and the braking force increases, thereby reducing the angular velocity of the flywheel 14.

If the above is represented in a block diagram, it will be as shown in FIG. In the figure, Ke is the conversion gain of the F-V converter 23, Kt is the total conversion gain of the drive amplifier 27 and the coil 21b,
EB is a bias voltage.

From this block diagram, the angular velocity Ω can be expressed as follows.

T-TL-EBKt Ω=□ S (J +K e K t) As is clear from comparing this equation with the conventional angular velocity equation mentioned above, the equivalent moment of inertia changes from J to J+
Ke)(t).

Note that the Ke and KtO values are determined by the F-V converter 23 and amplifier 27.
It can be arbitrarily varied by changing the gain, and the equivalent moment of inertia can be increased or decreased accordingly.

Incidentally, in the above embodiment, the photocoupler 22 for detecting the rotation of the flywheel 140 is provided integrally with the core 21a of the electromagnetic braking device 21, but it may be provided elsewhere.

Further, although the relationship between the disc 20 and the braking device 21 constitutes an eddy current type brake, its shape is not limited to that shown in the drawings.

〔Effect of the invention〕

As explained above, according to the present invention, by applying a braking force in the opposite phase to the disturbance torque to the flywheel, it is equivalent to arbitrarily increasing the moment of inertia. This results in a flywheel effect that can suppress the

[Brief explanation of drawings]

FIG. 1 is a partial block diagram showing an embodiment of the present invention, FIG. 2 is a plan view of a portion of FIG. 1, FIG. 3 is an enlarged sectional view of a portion of FIG. 1, and FIG. 4 is a block diagram equivalently showing the configuration of FIG. 1, FIG. 5 is a diagram showing a conventional example,
FIG. 6 is a block diagram equivalently showing the configuration of FIG. 5. 14...Flywheel, 21...Electromagnetic braking device, 22...Photocabra, 23...
... Frequency-voltage converter, 24 ... Differentiation circuit, 25 ... Bias voltage generator, 27 ...
...drive amplifier.

Claims (1)

[Claims] A rotatably supported flywheel, a detection means for detecting the angular velocity of the flywheel, a means for differentiating the output of the detection means to detect a change in the angular velocity, and an electromagnetic force for applying electromagnetic power to the flywheel. Equipped with a braking device,
A flywheel device characterized in that the braking force of the electromagnetic braking device is controlled based on the detected change in angular velocity to compensate for the change in angular velocity.