KR0168575B1 - Improved drum motor driving apparatus for use in a vcr - Google Patents

Abstract

The present invention relates to an improved V. C. R. drum motor driving apparatus, comprising: a switching hall element (10) for generating a positive voltage induced by a magnet (2), and a switching hall element (10). The first transistor Q1 is turned off when the positive voltage induced by the magnet is provided and the turn-off when the positive voltage induced by the switching hall element 10 is provided. The second transistor Q2 that is turned on, the third transistor Q3 that is turned on when the first transistor Q1 is turned off, and the selector terminals and the third transistor Q3 of the third transistor Q3 are turned on. The first and second coils La and Lb which are connected in parallel to each other between the collector terminals of the two transistors Q2 and induce magnetic flux by a DC power supply provided from the power supply terminal Vcc are configured.

Therefore, in the present invention, since the magnetic flux induced from the coils wound in opposite directions acts on the magnet at the same time, the driving force is improved, the initial driving is smoothed, the consumption of the rated current is reduced, and the rotation is uniform and smooth. It is effective to prevent jitter and to execute accurate speed control. In addition, since only one switching Hall element is used, the production cost can be reduced.

Description

Improved VC's drum motor drive

1 is a schematic cross-sectional view of a conventional drum motor.

2 is a schematic circuit diagram of a conventional conventional drum motor driving apparatus.

3 is a schematic diagram for explaining driving of a conventional drum motor.

4 is a circuit diagram of a drum motor driving apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

1: rotor case 2: magnet

3: driving coil 4: stator core

5: printed circuit board 6: rotor

7,10: Switching Hall element A, B: Hall element input terminal

L: Coil Q: Transistor

R: resistance φ: magnetic flux

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum motor driving apparatus of a video cassette recorder (hereinafter abbreviated as V. C. Al.), In particular, to reduce the rotational vibration of the drum motor to improve the uniformity of rotation, An improved V. C. R. drum motor drive that reduces current consumption and facilitates initial operation.

Typically, a recording and playback head is used to perform functions such as recording and playback in a V.C. egg. By the way. This recording and reproducing head is mounted on a drum, which is commonly called a head drum.

On the other hand, when the V.C. egg is in the recording and reproducing mode, the drum on which the reproducing and recording heads are mounted rotates at a predetermined speed, thereby reproducing from the cassette tape proceeding at a constant speed or recording to the cassette tape.

In addition, a drum motor is generally used as a device for driving the head drum. A drum motor is generally divided into two parts, a stator and a rotor. Magnets are mounted on the inner and lower surfaces of the rotor, and a predetermined number of pulse generators generate pulses according to the rotation of the coil and the rotor. It is equipped with a switching Hall element for providing rotational force to the rotor.

After all, the drum motor of V. C. is largely composed of a rotor and a stator.

1 is a cross-sectional view showing a conventional V. C. drum motor.

As shown in FIG. 1, a conventional V.C. drum motor includes a rotor case (1), a magnet (2), a stator core (4), a driving coil (3), and a printed circuit. board: PCB, rotating shaft 6, switching Hall element 7 is configured.

On the other hand, the driving of the drum motor is briefly described as follows.

The Hall effect occurs in the two switching Hall elements 7 under the influence of the magnetic field formed in the magnet 2, whereby a voltage is induced in the Hall element 7. The induced voltage is applied to the driving coil 3, and thus, the magnet 2 is moved by the change of the magnetic flux induced by the driving coil 3 to rotate the rotor of the drum motor to drive the drum motor. Done.

2 is a schematic circuit diagram of a conventional conventional drum motor drive device.

In Fig. 2, terminals A and B represent input terminals of two switching Hall elements 7, Vcc represents a supply power supply, and coils La and Lb are for driving wound around the stator core 4, respectively. The coil 3 is shown.

On the other hand, the operation of the conventional drum motor driving apparatus shown in Figure 2 as follows.

When a positive voltage induced from the switching hall element 7 by the N pole of the magnet 2 is applied to the input terminal A of the switching hall element 7, the pnp type transistor Qa is turned off. -off), and thus, the power supply Vcc is supplied to the coil La via the collector resistor Rc1 of the transistor Qa. As a result, magnetic flux is induced in the coil La.

Similarly, when a positive voltage induced in the switching hall element 7 by the N pole of the magnet 2 is applied to the input terminal A of the switching hall element 7, the transistor Qb is turned off. Therefore, the supply power source Vcc is supplied to the coil Lb via the collector resistor Rc2 of the transistor Qb, whereby magnetic flux is induced in the coil Lb.

Accordingly, as shown in FIG. 3, the magnetic flux induced in the coils La and Lb provides the driving force to the magnet 2, and as the magnet 2 rotates, the rotor is rotated about the rotor shaft 6. Rotate clockwise. That is, when magnetic flux is generated in the coil La, the rotor is driven by pushing the N pole of the magnet 2, and when the magnetic flux is generated in the coil Lb, the rotor is pulled by pulling the N pole of the magnet 2.

However, such a conventional V.C.R drum motor driving device generates a force on each of the N and S poles of the magnet to drive the drum motor, so that the rotation of the motor is uneven and rotational vibration occurs. There was a problem that it is difficult to accurately control the rotational speed of the motor.

Accordingly, the present invention has been made to solve this problem, and an object of the present invention is to improve the rotational vibration of the drum motor, improve the uniformity of the rotation, as well as improved v To provide the drum motor drive of C.R.

According to a preferred embodiment for achieving the above object, the present invention provides a drum motor driving apparatus of V. C. drum for smooth rotation of the V. C. drum motor having a magnet, a rotating shaft and a printed circuit board. The switching Hall device generates a positive voltage induced by the magnet, and is turned off when the positive voltage induced by the magnet in the switching hole is provided through an input terminal. A first transistor, a second transistor turned on when the positive voltage induced by the magnet in the switching Hall element is connected in parallel with the first transistor and turned on, and a positive DC power is supplied A third transistor connected to a power supply terminal and a collector terminal of the first transistor and turned on when the first transistor is turned off; And a first coil and a first coil connected in parallel between a collector terminal and a collector terminal of the second transistor to induce magnetic flux by a DC power supplied from the power supply terminal through the third transistor.

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

4 is a circuit diagram of a V. C. drum motor driving apparatus according to a preferred embodiment of the present invention.

As shown in FIG. 4, the present invention includes load resistors R1, R2, and R3, npn-type transistors Q2, pnp-type transistors Q1 and Q3, and coils La and Lb. .

From the input terminal A of the switching hall element (not shown), when a positive voltage induced in the switching hall element is applied through the resistor R1, the transistor Q1 of the pnp type is turned off and the transistor Q1 is turned off. The npn type transistor Q2 connected in parallel with is turned on.

At this time, as the transistor Q1 is turned off, the supply power source Vcc is applied to the emitter terminal of the pnp type transistor Q3 through the resistor R2.

On the other hand, the base terminal of the transistor Q3 is connected to the collector terminal of the transistor Q1.

The collector terminal of transistor Q3 is connected to coils La and Lb. The collector terminal of transistor Q2 is also connected to coils La and Lb. That is, coils La and Lb are connected between the collector terminal of transistor Q3 and the collector terminal of transistor Q2, and coil La and coil Lb are connected in parallel with each other.

Accordingly, since the transistor Q3 is of the pnp type, the transistor La is turned on by the voltage difference between the base terminal and the emitter terminal, and the power supply Vcc is connected in parallel to each other through the turned-on transistor Q3. And a coil Lb, that is, a current flows through the coil La and the coil Lb. Accordingly, magnetic fluxes? A and? B are induced in the coils La and Lb.

The current flowing through the coil La and the coil Lb flows through the transistor Q2 turned on by the induced voltage of the switching hall element provided through the input terminal A.

On the other hand, the coil La and the coil Lb connected in parallel with each other are wound in different directions, that is, in opposite directions. Therefore, the magnetic fluxes? A and? B are induced in opposite directions to each other. Therefore, the magnetic fluxes? A and? B induced by the coil La and the coil Lb act simultaneously on the magnet 2, which increases the driving force and provides the driving force more consistently.

In addition, the present invention uses only one switching Hall element, unlike the conventional art.

Therefore, in the present invention, since the magnetic flux induced from the coils wound in opposite directions acts on the magnet at the same time, the driving force is improved, the initial driving is smoothed, the consumption of the rated current is reduced, and the rotation is uniform and smooth. It is effective to prevent jitter and to execute accurate speed control. In addition, since only one switching Hall element is used, the production cost can be reduced.

While the invention has been shown and described with reference to certain preferred embodiments, those skilled in the art will recognize that various modifications and changes can occur without departing from the spirit and scope of the invention as set forth in the following claims.

Claims (6)

In the drum motor driving apparatus of V.C drum for smooth rotation of the V. C drum motor having a magnet (2), a rotating shaft (6) and a printed circuit board (5), the magnet (2) The switching Hall element 10 generating the positive voltage induced by the positive electrode and the positive voltage induced by the magnet in the switching Hall element 10 are input terminals A of the switching Hall element. A first transistor Q1 that is turned off when provided through; A second transistor Q2 connected in parallel with the first transistor Q1 and turned on when a positive voltage induced by the magnet 2 in the switching hall element 10 is provided through an input terminal; ; A third transistor Q3 connected to a power supply terminal Vcc to which a positive DC power is supplied and a collector terminal of the first transistor Q1, and to be turned on when the first transistor Q1 is turned off; Wow; A parallel connection between the collector terminal of the third transistor Q3 and the collector terminal of the second transistor Q2 is connected in parallel to a DC power source provided from the power supply terminal Vcc through the third transistor Q3. An improved V. C. drum motor drive comprising first and second coils (La, Lb) for releasing magnetic flux by means of. 2. The improved V. R. drum motor driving device according to claim 1, wherein the first and third transistors (Q1, Q3) are pnp type transistors. 2. An improved V. C. drum motor drive according to claim 1, wherein said second transistor (Q2) is an npn type transistor. 2. An improved V. C. drum motor drive according to claim 1, characterized in that the first coil (La) and the second coil (Lb) are wound in opposite directions. 2. The improved V. R. drum motor driving device according to claim 1, wherein the switching hall element (10) mounted on the printed circuit board (5) is one. The magnetic flux induced by the first coil La and the second coil Lb is a diameter? A and? B that the magnet 2 acts simultaneously to drive the drum motor. VC's drum motor drive.