KR940003821Y1 - Driving circuit of horn - Google Patents

Abstract

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Description

Drive circuit of horn

1 is a cross-sectional view showing an example of a typical horn to which the present invention is applied.

2 is a driving circuit of the horn according to the present invention.

3 is another driving circuit of the horn according to the present invention.

4 is another driving circuit of the horn according to the present invention.

5 is another driving circuit of the horn according to the present invention.

The present invention relates to a car horn, and more particularly, to a driving circuit for removing the spark noise generated by the switch contact when the horn is operated.

Car horns are usually classified according to the shape and appearance of the sound source, and most typically, there is a balance and a cell type. In connection with this tendency it may be highly desirable to induce the operation of a balanced horn like a cell.

That is, in the conventional horn, since a large current (about 3 A) flows during the operation of the horn switch, noise is generated by the spark at the contact portion. At this time, the noise further acted as a powerful source of noise affecting other electric and electronic circuit systems of the vehicle, causing troubles for other systems. In addition, the spark at the contact point caused a problem about the durability of the horn. That is, the conventional horn is usually operated as follows.

As shown in FIG. 1, the horn 20 is composed of a truncated lower case 2 which is bent in a step shape and a diaphragm 10 serving as an upper cover thereof. The lower side of the case 2 is supported by the bracket 3 and fixed by a bolt 13 or the like. The case 2 is equipped with a ferromagnetic electromagnet 1 at the lower center inside thereof.

The coil part 4 is fixed to the circumference | surroundings of this electromagnet 1 by the plate 8 at a somewhat larger height, and is separated from the electromagnet 1 by the predetermined gap in the state inserted into this coil part 4. An amateur 11 is installed. In the amateur 11, the protrusion 14 protrudes a predetermined length from the predetermined height to the outer circumference. The armature 11 is fixed at its upper end by the gasket 9 of the upper circumference of the case 2 while the diaphragm 10 and the baffle 12 are movably fixed thereto.

Projection portion 4 is formed around the armature 11, the chopper 5 is fixed to one side by a bolt 15 on one side forming a step portion around the circumference of the case 2, the movable contact point ( 6) is fixed at the lower part thereof, and a fixed contact point 7 is formed at the upper part thereof.

The movable contact 16 is fixed to the movable contact 16 so as to be in contact with the fixed contact 17 made of tungsten between the stationary contact 7. Therefore, when the armature 11 moves downward, the projection 14 causes the fixed contact 17 and the movable contact 16 to fall, and the fixed contact 17 and the movable contact 16 come into contact with each other during the upward movement.

In such a horn 20, a power supply switch thereof is directly connected to the coil unit 4. Therefore, when the switch attached to the horn 10 is pressed, a current flows in the coil part 4 to attract the magnet 11 fixed to the baffle 12 while magnetizing the electromagnet 1 to give magnetic force. The projection 14 of the armature 11 is moved downward by a predetermined distance to push the movable contact 6 to cut off the current. At this time, the amateur 11 loses magnetism, but after the collision with the electromagnet 1 by the inertial force is raised by the restoring force of the baffle 12.

When the armature 11 is raised, the movable contact table 6 is raised again and its movable contact 16 is in contact with the fixed contact 17 so that current flows.

In this state, even though a current flows, the current continues to rise due to the inertia force of the armature 11 and then downward again due to the magnetic force and the restoring force of the baffle 12.

This process is repeated in a moment, so that the baffle 12 is shaken by shaking, so that the alarm buzzes.

As described above, the horn operating in the same manner as described above could not avoid the occurrence of the spark at the power-on switch as well as the spark between the movable contact 16 and the fixed contact 17, and thus the mechanical noise caused by it. Not only was it impossible, but the influence of this noise on other electrical and electronic circuits could not be ignored.

In view of these points, it is an object of the present invention to provide a drive circuit of a horn which eliminates spark generation at the horn and the voltage application switch of the horn.

The present invention has another object of having an aftershock function to maintain the self resonance of the horn. Therefore, the present invention is to remove the spark noise in the power supply switch of the horn and the movable and fixed contact point, and at the same time to improve the resonance of the baffle due to the operation, to minimize the applied current to the voltage application switch of the horn. A first transistor having a base current limiting means (R3), an emitter voltage fixing means, a second transistor that is saturated in response to a trigger current of the first transistor, and, if necessary, a trigger of the first transistor. Since the current is stored and the operation of the horn and the operation of the second transistor are delayed for each time the operation of the horn and the opening of the fixed contact point are provided, it is provided with means for maintaining the repetitive vertical movement of the amateur for a certain period.

The present invention will be described in detail with reference to the accompanying drawings. In FIG. 2, FIG. 3, FIG. 4, and FIG. 5, the same code | symbol is attached | subjected about the same component as FIG. 1, and the detailed description is abbreviate | omitted.

In FIG. 2, the horn 20 is schematically shown an amateur 11, a fixed contact 17, a movable contact 16, an electromagnet 1 and a coil 4, but the configuration thereof is the same as that of FIG. .

The horn drive circuit is composed of the horn 20 and a drive circuit for operating the horn. The driving circuit includes a transistor T1, which is a PNP type, and resistors R1 and R3, which limit the self-driving current, are connected to the base thereof together with the power supply switch SW1.

The emitter of the transistor T1 is connected to one side of the movable contact 16 via a resistor R2 which limits its driving voltage, and its collector is connected to the base of the transistor T2. The transistor T2 is a power transistor and may be a bipolar NPN power transistor or an N-channel FET.

The collector of the transistor T2 is connected to the power supply V1 and to the fixed contact point 7, and one end of the coil 4 is connected to the emitter thereof, and the other end of the coil 4 is It is grounded.

With this configuration, the present invention works as follows. That is, while the power switch SW1 is turned on, the transistor T1 is triggered and the transistor T2 is turned on. At this time, the current flows to the coil 4 to magnetize the electromagnet 1 so that the armature 11 is moved downward, so that the movable and fixed contact points 6 and 7 are open. Therefore, the applied current to the coil 4 is cut off and the electromagnet loses its magnetism.

The armature 11 then causes the transistors T1 and T2 to turn on and the armature (T1) and T2 to be turned on again by the restoring elastic force of the baffle 12 as in FIG. 11) is pulled by the magnetic force of the electromagnet (1).

As described above, the voltage applied to the switch SW1 is limited by the drive current of the transistor T1, and the voltage applied when the movable contact 6 and the fixed contact 7 are short-circuited. Since the current flow is limited to R1, R2, and R3), noise at the switch SW1 due to sparks can be prevented. Furthermore, FIG. 3 is the same as in FIG. 2 except that the capacitor C1 is connected to the collector of the transistor T1 in comparison with FIG.

The capacitor C1 is charged when the horn switch SW1 is turned on and off, and is discharged when the horn switch SW1 is opened to excite the coil 4 for a predetermined period, so that the baffle 12 can be extended by the armature 11. In conclusion, the horn itself should be maintained.

4 is the same as in FIG. 2 except that the coil 4 is arranged in the emitter of the transistor T2.

Since the coil 4 is connected to the emitter of the transistor T2, it has a predetermined delay time for the electronics 1, thereby clarifying the magnetization period.

5 is the same as in FIG. 4 except that a delay circuit composed of a resistor R4 and a capacitor C1 is connected to the collector of the transistor T1.

Similarly, in the embodiment of FIG. 5, the capacitor C1 at the time of the horn switch SW1 is charged and discharged at the time of off to maintain the excitation in relation to the horn resonance.

Claims (4)

In an electric horn used in an automobile, a peripheral portion is fixed to the horn housing, and the armature is provided with a diaphragm 10 having an armature 11 attached thereto, a coil 4, and the armature 11 below. An electromagnet (1), which is normally closed and is composed of a pair of closed and fixed contacts (17) and a movable contact (16), one of which is connected in series with the interrupter Positions adjacent to the horn switch SW1 and the at least one second trigger switch means T2 connected to the coil 4 and interrupting the excitation current supplied to the coil of the electromagnet 1 and the armature 11. And connected to its control input to turn on and off the second trigger switch means T2, and connected to the interrupter 5, which is opened by the downward movement of the armature 11, through the current limiting means R2. , Through the current limiting means (R3) to the switch And a spark prevention circuit comprising first limiting switch means (T1) connected to each other, current limiting means (R1) and (R3) connected in series between the interrupter (5) and the horn switch (SW1). Drive circuit of the horn. The drive circuit for a horn according to claim 1, wherein the first trigger switch means (T1) of the spark prevention circuit is a PNP transistor, and the horn switch (SW1) is located between ground and the interrupter (5). 2. The spark preventing circuit according to claim 1, wherein the spark prevention circuit includes a second trigger switch means T2 of NPN transistors, a first trigger switch means T1 of PNP transistors, and a control input of the second trigger switch means T1. The horn switch SW1 connected between the ground and ground, the first current limiting resistor R3 connected between the control input of the first trigger switch means T1 and ground, and the control of the first trigger switch means T1. And a second current limiting resistor (R4) connected to an input and a control input of the second trigger switch means (T2). 4. The spark prevention circuit according to claim 3, wherein the spark prevention circuit causes the on and off cycles of the trigger switch means to be repeated for a predetermined period when the exciting current flowing through the coil 4 gradually decreases when the horn switch SW1 is opened. A horn drive circuit comprising: a means.