JP2000142220A - Horn driving circuit for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely operate a horn for an automobile only when the drive is directed. SOLUTION: In a usual state, a capacitor C4 is charged with a battery 4 through an exciting coil 31, connecting part 2, resistance R4 for current limiting, and a diode D2. A transistor Q2 turns on and a transistor Q3 turns off by an inducing voltage of a coil 1 caused by oscillation of a LC oscillator 11. Only a charging current of the capacitor C4 and a current to the LC oscillator 11 flow to the exciting coil 31, the current more than a predetermined level does not flow, and a normally opening contact part 32 is turned off. When the transistor Q3 turns on, the on of the transistor Q3 is continued by the charging electric power of the capacitor C4, so that a horn 5 operates surely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horn drive circuit for a vehicle, which is disposed on a steering wheel and drives a horn for a vehicle.

[0002]

2. Description of the Related Art Generally, an operating unit for instructing driving of an automobile horn is provided on a steering wheel. Conventionally, an automobile horn driving circuit for driving an automobile horn is provided inside the steering wheel. Have been. by the way,
The steering wheel of the motor vehicle is configured to make several turns clockwise and counterclockwise in total. Therefore, the configuration of the connection portion is devised so that the electrical connection between the vehicle horn drive circuit inside the handle and the vehicle-mounted battery is reliably maintained even when the handle rotates.

[0003]

Power is supplied from the vehicle-mounted battery to the horn drive circuit for the vehicle via this connection. However, irrespective of the configuration of such a connection, the vehicle is driven by the operation unit. It is necessary to prevent the operation of the horn when the driving of the horn is not instructed, and to reliably operate the horn for the vehicle only when the driving is instructed.

[0004] The present invention has been made in view of the above,
It is an object of the present invention to provide a vehicle horn drive circuit capable of reliably operating a vehicle horn only when driving is instructed.

[0005]

According to the present invention, there is provided a horn circuit for a vehicle, which is disposed on a handlebar and electrically connected to a vehicle-mounted battery via a connection portion, and is provided with a conductor portion exposed to the outside of the handlebar. And a charging circuit unit connected to the connection unit and charged by power supplied from the vehicle-mounted battery; a switch element connected between the connection unit and ground; and a skin in contact with the conductor. And a switch control circuit unit that turns on the switch element by the charging power of the charging circuit unit only while the horn is being driven, and the horn is driven when a predetermined current flows from the vehicle-mounted battery to the connection unit. (Claim 1).

According to this configuration, when the skin is not in contact with the conductor, the switch element is turned off, a predetermined current does not flow from the vehicle-mounted battery to the connection portion, and the horn is not driven. The charging circuit is being charged by the electric power. When the skin comes into contact with the conductor, the switch element is turned on, so that the power supply from the vehicle-mounted battery to the charging circuit is stopped, and a predetermined current flows from the vehicle-mounted battery to the ground through the connection part and the switch element. Flow, which drives the horn.
At this time, the ON of the switch element is maintained by the charging power of the charging circuit unit only during the period in which the skin is in contact with the conductor, so that the driving of the horn is continued.

Further, in the horn drive circuit for an automobile according to the present invention, the switch element is connected to a control terminal connected to the charging circuit section, the connection section and ground, respectively, and is connected to the control terminal. A switch control circuit section that is connected between the control terminal and the ground and is in contact with the conductor section while the skin is in contact with the switch section. A switch unit that is turned off only by the switch (claim 2).

According to this configuration, the switch is turned off only while the skin is in contact with the conductor, and when the connection between the control terminal and the ground is opened, the charging power of the charging circuit is applied to the control terminal. When a voltage is applied to turn on the pair of switch terminals and the connection portion is connected to the ground, a predetermined current flows from the vehicle-mounted battery to the connection portion, and the horn is driven. Here, since the connection portion is connected to the ground, power supply from the vehicle-mounted battery to each portion is stopped, but the pair of switch terminals are kept on by the charging power of the charging circuit portion. On the other hand, when the skin is not in contact with the conductor, the switch is turned on, and the connection between the control terminal and the ground is made. Is released and the horn is not driven.

Further, in the horn drive circuit for an automobile according to the first or second aspect, a resistance element is provided between the connection section and the charging circuit section.

[0010] According to this configuration, since the resistance element is interposed between the connection portion and the charging circuit section, an increase in the charging current level from the vehicle-mounted battery to the charging circuit section is suppressed by the resistance element. In other words, even when the voltage of the charging circuit section is reduced, the charging current from the vehicle-mounted battery to the charging circuit section does not become the predetermined current, whereby the horn is surely prevented from being inadvertently driven.

[0011]

FIG. 1 is a circuit diagram of an embodiment of a horn drive circuit for an automobile according to the present invention, and FIG. 2 is a diagram showing a schematic configuration of a connection portion.

This horn drive circuit for an automobile is composed of an electric circuit 1, a connecting portion 2, an electromagnetic relay 3, and a vehicle-mounted battery 4 disposed inside a handle (not shown), and drives the horn 5. It is.

As shown in FIG. 2, the connecting portion 2 includes a ring-shaped fixed conductor portion 21 and a rotating conductor portion 23 pressed by a leaf spring 22 against the fixed conductor portion 21 with a required pressing force.
The rotating conductor portion 23 slides on the fixed conductor portion 21 in accordance with the rotation of the handle, whereby the connection portion 2 is connected regardless of the rotation state of the handle.
, The electrical connection is maintained.

As shown in FIG. 1, the fixed conductor 21 is connected to the positive electrode of the battery 4 via the exciting coil 31 of the electromagnetic relay 3. On the other hand, the rotating conductor portion 23 is connected to the anode of the diode D2 via the current limiting resistor (resistance element) R4 and to the drain (switch terminal) of the field effect transistor (switch element) Q3. The cathode of the diode D2 is connected to the power supply line 6.

The power supply line 6 is (1) grounded via a capacitor (charging circuit section) C4. (2) Connected to the gate (control terminal) of the transistor Q3 and the collector of the NPN transistor Q2 via the bias resistor R3. (3) NPN transistor Q via bias resistor R1
1 base. (4) It is connected to the collector of the transistor Q1 via the second coil L2 magnetically coupled to the parallel tuning coil L1.

The base of the transistor Q1 is connected to the anode of the diode D1 and the tap of the parallel tuning coil L1 via the coupling capacitor C1. One end of the parallel tuning coil L1 is connected to a conductive touch plate (conductor portion) 7, and the other end is connected to the cathode of the diode D1 via a capacitor C2. The cathode of the diode D1 is further connected to the base of the transistor Q2 via a resistor R2 and a capacitor C
3 is grounded. The emitter of the transistor Q2 and the source (switch terminal) of the transistor Q3 are grounded.

The horn 5 is connected to the positive electrode of the vehicle battery 4 via the normally open contact 32 of the electromagnetic relay 3. The normally open contact portion 32 is configured to be turned on when a current of a predetermined level or more flows through the exciting coil 31.

The touch plate 7 is exposed on the surface of a handle (not shown), and is configured so that the skin of the driver's finger or the like comes into direct contact.

The parallel tuning coil L1, the second coil L2, the transistor Q1 and the coupling capacitor C1 are formed by a known LC.
The oscillation circuit 11 is configured. In addition, LC oscillation circuit 1
1, capacitors C2 and C3, diode D1, resistor R2
The transistor Q2 constitutes the switch control circuit unit 12.

Next, the operation of the horn drive circuit for an automobile will be described. In the normal state, the capacitor C4 is charged by the vehicle-mounted battery 4 via the exciting coil 31, the connection portion 2, the current limiting resistor R4, and the diode D2. Further, the coils L1 and L2 of the LC oscillation circuit 11 oscillate, and the induced voltage generated in the parallel tuning coil L1 by this oscillation is rectified by the diode D1 and smoothed by the capacitors C2 and C3. The base potential of Q2 rises and transistor Q2 is turned on. Since the gate of the transistor Q3 is grounded by turning on the transistor Q2,
Transistor Q3 is off.

Therefore, in this state, the charging current of the capacitor C4 and the LC current are supplied to the exciting coil 31 of the electromagnetic relay 3.
Only the current for oscillation of the oscillation circuit 11 flows, but no current of a predetermined level or more flows, and the normally open contact portion 32 is off.

In this state, when the driver brings the skin into direct contact with the touch plate 7, the Q
Is greatly reduced, so that oscillation stops.

When the oscillation of the LC oscillation circuit 11 stops, the transistor Q2 is turned off because the base potential of the transistor Q2 decreases, whereby the gate of the transistor Q3 is turned on by the voltage applied from the power line 6 via the bias resistor R3. The potential rises and the transistor Q3 turns on. When the transistor Q3 is turned on, a current of a predetermined level or more flows through the exciting coil 31 of the electromagnetic relay 3, and the normally closed contact portion 32 is turned on. The power is supplied to the horn 5, and the horn 5 is activated to generate an alarm sound.

At this time, the power supply from the vehicle-mounted battery 4 to the power supply line 6 is stopped by turning on the transistor Q3, but the gate potential of the transistor Q3 is maintained by the charging power of the capacitor C4. Is continued.

As described above, according to the present embodiment, the capacitor C4 is charged in a normal oscillation state, and when the oscillation is stopped by the driver's operation and the transistor Q3 is turned on, the capacitor C4 is charged. Since the ON state of the transistor Q3 is maintained by the charging power, the driving of the horn 5 can be suitably performed.

Even if the connecting portion 2 chatters at the time of starting the engine or the like, the oscillation of the LC oscillation circuit 11 is continued by the charging power of the capacitor C4. Current does not flow to a predetermined level or more, and the off state of the normally open contact portion 32 is maintained, whereby it is possible to reliably prevent the horn 5 from being carelessly driven.

When the contact of the skin with the touch plate 7 is continued for a required time and the charging power of the capacitor C4 becomes almost zero, the skin is separated from the touch plate 7 and the transistor Q3 is turned off. And an inrush current flows from the vehicle-mounted battery 4 as a charging current for the capacitor C4. Since the inrush current is suppressed by the current limiting resistor R4, the electromagnetic relay 3 is turned on and the horn 5
Can be reliably prevented from operating. The current limiting resistor R4 can achieve the above function by adopting a resistor having a resistance value of about 100Ω.

Further, by using a relatively large capacitor of about 1000 μF as the capacitor C4, the transistor Q3 can be kept on for several seconds, and the operation of the horn 5 can be continued for a practically sufficient time. can do.

The present invention is not limited to the above embodiment, but can adopt the following modified embodiments. (1) In the above embodiment, a so-called base tuning type LC anti-coupling oscillation circuit is adopted as the LC oscillation circuit 11, but the present invention is not limited to this. May be adopted.

(2) In the above embodiment, the capacitor C4 is employed as the charging circuit unit.
A secondary battery may be used.

(3) In the above embodiment, the electromagnetic relay 3 is used. However, the present invention is not limited to this, and the horn 5 may be directly connected between the vehicle-mounted battery 4 and the connection part 2 as shown in FIG. It may be. Also in this case, when a current of a predetermined level or more flows from the vehicle-mounted battery 4 to the connection unit 2, the horn 5 is driven, and the same operation as in the above embodiment is performed, and the same effect can be obtained.

(4) In the above embodiment, the oscillation circuit is employed as a component of the switch control circuit section, but the invention is not limited to this. FIG. 4 is a circuit diagram showing a configuration example of a different switch control circuit unit.

In FIG. 4, a capacitor C3, a transistor Q2, a P-channel MOS field effect transistor Q4, N
Channel MOS field effect transistor Q5, PNP transistor Q6, resistors R5 to R7, and diodes D3 and D
4 constitutes the switch control circuit unit 12.

In the switch control circuit section 12, the power supply line 6 is grounded via a series circuit of (1) forward diodes D3 and D4. (2) The resistor R5 is connected to the connection point of the diodes D3 and D4, the gate of the transistor Q4, and the gate of the transistor Q5. (3) Connected to the source of transistor Q4.

The base of the transistor Q6 is connected to the drain of the transistor Q4.
6 is connected to the drain of the transistor Q5, and is grounded via the capacitor C3. Transistor Q
6 has its emitter connected to the gate of transistor Q3,
The collector is grounded. The source of the transistor Q5 is grounded. In addition, the touch plate 7
It is connected to a connection point of diodes D3 and D4 via a resistor R7.

In such a configuration, by adopting a resistor having an appropriate resistance value as the resistor R5, in a normal state, a gate voltage lower than the threshold level is applied to the P-channel MOS field effect transistor Q4, and an N-channel MOS transistor is applied. A gate voltage higher than the threshold level is applied to the field effect transistor Q5, whereby the transistor Q4 is turned off and the transistor Q5 is turned on. Therefore, transistor Q6
, The base current flows out, so that the transistor Q6 is turned on.

When the skin comes into contact with the touch plate 7, an induced hum enters from the touch plate 7 via the resistor R7, and the rectification of the diode D4 causes the gate potentials of the transistors Q4 and Q5 to go to a minus level. This turns on the transistor Q4 and turns off the transistor Q5. Therefore, transistor Q6
Is connected to the power supply line 6 via the transistor Q4, and no base current flows out.
6 goes off.

By turning on / off the transistor Q6, the same operation as in the above embodiment is performed.
According to this embodiment, the same effect as the above embodiment can be obtained.

(5) In the above embodiment, the connecting portion 2 has a configuration in which the rotating conductor portion 23 slides on the fixed conductor portion 21 in accordance with the rotation of the handle, but is not limited to this. The configuration shown in FIG.

That is, the connecting portion 2 shown in FIG. 5 includes a rotating member 24 fixed to a handle shaft (not shown) and a hole 25a provided on a steering column (not shown) side for inserting the cylindrical portion 24a of the rotating member 24. Under cover 2 with
5. End support 2 that is loosely fitted outside the cylindrical portion 24a
6. A flat cable 27 attached to the outside of the end support 26 and accommodated in the under cover 25, and an upper cover 28 for closing the opening of the under cover 25.

The flat cable 27 is housed in an annular space 29 formed between the under cover 25 and the upper cover 28 while being wound around the cylindrical portion 24a via the end support 26. The connector 27a provided at one end is fixed to the rotating member 24, and the connector 27b provided at the other end is fixed to the under cover 25.
Is rolled or unwound within the annular space 29 to move.

As shown in FIG. 6, the flat cable 27 is connected to the transistor Q3 via the connector 27a.
, And connected to the exciting coil L31 via the connector 27b.

According to this embodiment, the same operation as in the above embodiment is performed, and the same effect can be obtained.

[0044]

As described above, according to the first aspect of the present invention, the switch element connected between the connection portion and the ground is turned on only while the skin is in contact with the conductor portion, and the charging circuit is turned on. The switch element is kept on by the charging power of the part,
Since the horn is driven when a predetermined current flows from the vehicle-mounted battery to the connection portion, the horn can be driven only during the period in which the skin is in contact with the conductor, and the horn can be reliably driven only when the driving is instructed. Can be driven.

According to the second aspect of the present invention, the switch unit connected between the control terminal of the switch element and the ground is turned off only while the skin is in contact with the conductor, thereby charging the battery. A predetermined voltage is applied to the control terminal connected to the circuit section, a pair of switch terminals are turned on, the connection section is connected to the ground, and power supply from the vehicle-mounted battery is stopped. Thus, the pair of switch terminals are kept on, and the horn can be driven reliably.

According to the third aspect of the present invention, the resistance element is interposed between the connection section and the charging circuit section, so that the charging current level from the vehicle-mounted battery to the charging circuit section can be increased by the resistance element. Even if the voltage of the charging circuit unit is reduced, the charging current from the vehicle-mounted battery to the charging circuit unit does not reach the predetermined current, thereby preventing inadvertent driving of the horn. Can be.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of a vehicle horn drive circuit according to the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a connection unit.

FIG. 3 is a circuit diagram of another example of a horn drive circuit for a vehicle.

FIG. 4 is a circuit diagram illustrating a configuration example of a different switch control circuit unit.

FIG. 5 is a diagram illustrating a different configuration example of a connection unit.

6 is a circuit diagram of a horn drive circuit for an automobile using the connection unit of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric circuit 12 Switch control circuit part 2 Connection part 21 Fixed conductor part 23 Rotating conductor part 3 Electromagnetic relay 31 Exciting coil 32 Normally open contact part 4 In-vehicle battery 5 Horn 7 Touch plate (conductor part) 11 LC oscillation circuit C4 Capacitor (Charge Circuit section) Q3 Field effect transistor (switch element) R4 Current limiting resistor (resistance element)

Claims (3)

[Claims] 1. A horn circuit for an automobile, which is disposed on a steering wheel and is electrically connected to a vehicle-mounted battery via a connection portion, wherein the conductor portion is formed so as to be exposed outside the steering wheel, and is connected to the connection portion. A charging circuit portion charged by power supplied from the vehicle-mounted battery, a switch element connected between the connection portion and the ground, and a charging circuit portion of the charging circuit portion only while the skin is in contact with the conductor portion. A switch control circuit section for turning on the switch element by charging power, wherein the horn is driven when a predetermined current flows from the vehicle-mounted battery to the connection section. Horn drive circuit. 2. The horn drive circuit for an automobile according to claim 1, wherein the switch element is connected to a control terminal connected to the charging circuit unit, the connection unit and ground, and is connected to the control terminal. A switch control circuit section that is connected between the control terminal and the ground and is in contact with the conductor section while the skin is in contact with the switch control circuit section. A horn drive circuit for an automobile, comprising a switch unit that is turned off only. 3. The horn drive circuit according to claim 1, wherein a resistance element is interposed between said connection portion and said charging circuit portion.