JPS6158486A - Servo motor - Google Patents

Abstract

PURPOSE:To similarly approximate the recording densities at the inner and outer peripheral surfaces of a disk by dividing the frequency input to a speed controller to control to switch the speed of a motor into a plurality of stages. CONSTITUTION:An oscillating frequency in response to the rotating speed is induced by a signal generator 11 by the rotation of the rotor of a motor 12, and the signal of the frequency is input to a speed controller 18 through a frequency divider 28. The controller 18 generates a voltage 20 proportional to the input frequency. This voltage 20 is initialized by the time constant of the variable resistor 22 of a time constant circuit 19, a resistor 23 and an capacitor 21. When the magnetic recording position of a floppy disk 26 is altered from the inner to the outer peripheral surfaces, the projection 33 of an arm 32 closes a time constant changeover switch 24 to shortcircuit a frequency divider 28 inserted between an amplifier 17 and the controller 18. Thus, the rotation of the motor 12 is doubled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a servo motor device, and more particularly to a device for controlling the rotation speed of a servo motor used in a magnetic recording device such as a floppy disk.

(Prior Art) As shown in FIG. 5, this type of conventional servo motor device forms a pattern for signal generation on a wiring board, moves along this pattern, and is polarized to an arbitrary number of poles. A signal generator 1 is configured by installing a magnet on the rotor and generates a signal with an oscillation frequency proportional to the rotation speed of the rotor, and a signal generated in the signal generator 1 is inputted to preset a time constant circuit 2. The output voltage of the speed controller 3 is supplied to a motor drive transistor 4, which controls the motor 5. A configuration is adopted in which the voltage is controlled and the rotation speed of the motor 5 is controlled.

In this conventional servo motor device, the rotation of the rotor of the motor 5 induces an oscillation frequency in the signal generator 1 according to the rotation speed, and a signal of this frequency is input to the speed controller 3. 3 is a type of frequency-voltage converter that generates a voltage proportional to the input frequency, and this voltage t is determined by the time constant of the resistors 6 and 7 of the time constant circuit 2 and the capacitors 1 and 8. If the rotation speed of the motor 5 is constant, the time constant is also constant, so the voltage generated from the speed control section 3 is constant, the motor 5 is rotated at a constant rotation speed, and when a load is applied to the motor 5, the voltage generated by the speed control section 3 is constant. As the rotation speed decreases, the oscillation frequency of the signal generator 1 becomes low, the voltage generated by the speed control section 3 increases, and the rotation speed of the motor 5 increases. The voltage generated by section 3 is reduced and the rotational speed of motor 5 is reduced.

[Problem that the invention seeks to solve]

When this conventional servo motor device is used in a floppy disk magnetic recording device, the disk is rotated at a constant speed, but the relative speed between the disk and the head is faster at the outer circumference of the disk than at the inner circumference.

Magnetic recording has the following basic characteristics.

λ=v/f λ: Recording wavelength, ■: Signal frequency, f: Relative speed This formula indicates that the faster the relative speed, the more data can be recorded.In a circular disk magnetic recording device, the relative speed on the inner circumference side The recording density will be determined. Furthermore, the recording density differs between the outer circumference and the inner circumference of the disk, which poses the problem of complicating the reproducing circuit.

The present invention has been made in view of the above-mentioned problems, and it divides the frequency input to the speed control unit to control the rotational speed of the motor by switching it to multiple stages, thereby recording information on the inner and outer peripheries of the disk. The present invention provides a servo motor device in which the density can be approximated.

[Means for solving problems]

The servo motor device of the present invention includes a signal generating section that generates a signal with a frequency proportional to the number of rotations, and a signal generated by the signal generating section that is input to generate a voltage corresponding to the frequency of this input signal. comprising a speed control section and a motor whose rotational speed is controlled by the output voltage of the speed control section, and a frequency division circuit that divides the frequency generated by the signal generation section,
The present invention is characterized in that a changeover switch is provided for inputting a frequency signal divided by the frequency dividing circuit to the speed control section.

[Effect]

In the servo motor device of the present invention, an oscillation frequency corresponding to the rotation speed is induced in the signal generating section by the rotation of the rotor of the motor, and a signal of this frequency is input to the speed control section. - If the voltage converter generates a voltage proportional to the frequency input, and the motor rotation speed is constant, the voltage generated from the speed control section will be constant, the motor will rotate at a constant rotation speed, and the motor will be loaded. When , the rotation speed of the motor decreases and the oscillation frequency of the signal generator decreases.
The voltage generated by the speed control section is increased, and the rotation speed of the motor is increased, and when the rotation speed of the motor is increased, the voltage generated by the speed control section is decreased, and the rotation speed of the motor is decreased. Then, the frequency input to the speed control section is divided by the switching operation of the changeover switch that switches to the frequency division circuit that divides the frequency of the signal generation section, and the output voltage of the speed control section is switched to a different value, and the rotation speed of the motor is changed. This is to switch and adjust.

〔Example〕

The structure of an embodiment of the present invention will be explained with reference to FIGS. 1 to 4.

A signal generator 11 outputs a signal with an oscillation frequency proportional to the number of rotations of the motor 12. This signal generating section 11
Print distribution as shown! ! It has a pattern 14 for signal generation formed of a conductor on the base 113, and an arbitrary number of polarized poles as shown in FIG. The magnet 15 rotates integrally with the rotor of the motor 12, and the magnet 15 is moved at the same rotational speed as the motor 12. This movement of the magnet 15 causes the magnet 15 to
Since the magnetic flux generated from the pattern 14 crosses the conductor of the pattern 14, an alternating current potential is generated in the pattern 14. Since the oscillation frequency generated by the signal generator 11 is proportional to the number of patterns 14, the signal generator 11 generates a signal (AC potential 1G) with a frequency proportional to the number of rotations of the motor 12.

An amplifier 17 amplifies the frequency generated by the signal generating section 11.

Reference numeral 18 denotes a speed control section, which constitutes a kind of frequency-voltage converter, which inputs the signal generated in the signal generation section 11 and converts the frequency of the input signal based on a time constant set in advance by a time constant circuit 19. A voltage 20 with a stepwise waveform corresponding to the voltage 20 is generated. The time constant circuit 19 includes a capacitor 21 connected in series.
, a speed adjusting variable resistor 22 and a resistor 23.

Further, a changeover switch 24 is connected between the amplifier 17 and the speed control section 18.
One contact 25 is directly connected to the speed control section 18, and the other contact 26 is connected to a frequency divider, e.g., flip 70 knob 2.
7 and this flip-flop 27 is connected to the amplifier 17
The flip 70 knob 27 is connected to the speed control section 18 so that the frequency output from the flip 70 is divided into 1/2 and this 1/2 frequency is input to the speed control section 18. In this way, by switching the changeover switch 24, the amplifier 1
7 is selectively connected to the speed control unit 18 via the frequency dividing circuit 28 or not via the frequency dividing circuit 28.

Further, the output voltage 20 of the speed control section 18 is supplied to the base of a motor drive transistor 29. The motor 12 is connected to the emitter side of this transistor 29, and the collector side of this transistor 29 is connected to the control power supply voltage VCC.
is supplied, and the rotation speed of the motor 12 is controlled.

The changeover switch 24 is opened and closed by a protrusion 33 of an arm 32 provided with a head 31 for magnetically recording on a floppy disk 30, which is a disc-shaped magnetic recording medium, as shown in FIG. The arm 32 moves along the radial direction of the disk 30 as the disk 30 rotates, and when the head 31 moves from approximately the center of the disk 30 in the half-t direction to the inner circumference, the protrusion 33 opens the switch 24. It looks like this.

Next, the operation of this embodiment will be explained.

The rotation of the rotor of the motor 12 induces an oscillation frequency in the signal generating section 11 according to the rotation speed, and a signal of this frequency (AC potential 1f3) is input to the speed control section 18; This voltage 20 is initially determined by the time constant of the variable resistor 22 and resistor 23 of the time constant circuit 19 and the condenser 21, and if the rotation speed of the motor 12 is constant, the time constant also changes. Since it is constant, the generated voltage 20 from the speed control section 18 is constant, and the motor 1
2 is rotated at a constant rotation speed, and the motor 12 maintains constant rotation. Also, when a load is applied to the motor 12, the motor 1
2 decreases, the oscillation frequency of the signal generator 11 becomes low, the voltage generated by the speed controller 18 increases, and the rotation speed of the motor 12 increases.Also, when the rotation speed of the motor 12 increases, The frequency of the signal 16 generated by the signal generator 11 also increases, the voltage 20 generated by the speed controller 11 decreases, and the rotation speed of the motor 12 decreases.Then, the magnetic recording position of the floppy disk 30 changes from the outer circumference to the inner circumference. When you turn to the side,
The protrusion 33 of the arm 32 switches the changeover switch 24,
By switching and opening the time constant changeover switch 24, the frequency dividing circuit 28 inserted between the amplifier 17 and the speed control section 18 is short-circuited. When this frequency dividing circuit 28 is inserted, the frequency of No. 18 and 16 generated by the signal generating section 11 is divided into 1/2 and input to the speed control section 18, and the output of this speed control section 18 is The output voltage is also reduced by 1/2, and the rotation speed of the monitor 12 is controlled to 1/2. Then, when the changeover switch 24 is turned on and off, the frequency of the signal generation section 11 is input to the speed control section 18, and the rotation speed of the motor 12 is doubled.

In this way, if the relative velocity on the outer circumference side of the floppy disk 30 is Vl, and the relative velocity on the inner circumference side is Vl, then the relative velocity 1, Vl changes, but the average relative 'a degree is Va, If the rotational speed of the motor 12 is set so that Vb is avb, the recording wavelength λ of the floppy disk 30 becomes approximately equal, and the recording density can be approximately equalized.

Furthermore, in the embodiment described above, a configuration in which one frequency dividing circuit 28 was formed was explained, but? It is also possible to provide a J2 number of frequency dividing circuits to switch the rotational speed of the motor 12 in multiple stages.

Further, the frequency dividing circuit 28 is limited to a frequency divider of the flip-flop 27, and there is no number, and a counter can also be used.
According to the counter, the rotation speed of the motor 12 can be changed to 1/2·N (g), and the viscosity, which approximates the recording density of a floppy disk, can be improved.

Note that the signal generating section 11 has been described as using a 4+1"r configuration using an oscillator that is a kind of power generator that oscillates a frequency, but it is also possible to use a pulse generator that generates a pulse signal with a frequency proportional to the number of rotations of the motor 12. You can also do it.

〔Effect of the invention〕

According to the present invention, a frequency dividing circuit is provided for dividing the frequency generated by the signal generating section, and a changeover switch is provided for inputting the frequency signal divided by the frequency dividing circuit to the speed control section. Therefore, by switching this changeover switch, the frequency of the input signal to the speed control section that controls the motor rotation speed can be selectively divided, and the output voltage of this speed control section can be switched to multiple levels. This allows the recording densities of the outer and inner peripheries of the floppy disk used to drive the disk to be approximately similar.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a servo motor device showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the pattern of the signal generating section same as above, and Fig. 3 shows the relationship between the pattern of the signal generating section same as above and the magnet. FIG. 4 is a side view of the operating section of the time constant changeover switch, and FIG. 5 is a circuit diagram of a conventional servo motor device. 11... Signal generation section, 12... Motor, 18... Speed control section, 26... Time constant changeover switch, 28... Frequency dividing circuit.

Claims (1)

[Claims] (1) A signal generation section that generates a signal with a frequency proportional to the rotation speed, a speed control section that inputs the signal generated by this signal generation section and generates a voltage corresponding to the frequency of this input signal, and this speed a motor whose rotational speed is controlled by the output voltage of the control section, a frequency dividing circuit for dividing the frequency generated by the signal generating section, and a signal of the frequency divided by the frequency dividing circuit. A servo motor device comprising a changeover switch for inputting input to the speed control section.