JPS6030126Y2 - Horn switch for steering wheel - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a horn switch for a steering wheel using a pressure-sensitive resistor.

In conventional vehicles, the horn switch on the steering wheel has only an ON-OFF function, and therefore the sound pressure of the horn warning sound is constant, making it unsuitable for warnings that require a wide variety of uses.

Furthermore, since the conventional horn switch as described above is of the stroke type, it is inconvenient that even if an emergency warning is required, it cannot respond instantly.

This proposal was devised in view of the shortcomings of the conventional steering wheel horn switch as described above, and its gist is that there are two types of pressure sensitive Along with overlapping the resistors,
A horn switch provided on either the upper or lower surfaces of the horn is interposed in a control circuit provided between the power source and the horn, and the loudness and tone of the warning sound from the horn can be adjusted. located on the horn switch for the steering wheel.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a steering wheel of a vehicle, and a horn switch 2 is disposed on the boss thereof.

The horn switch 2 is made by superimposing two types of pressure sensitive resistors with different electrical resistance characteristics.

In other words, as its cross section is shown enlarged in Figure 2, one pressure-sensitive resistor is made by mixing graphite powder into a polymer material such as rubber or synthetic resin, and its resistance value increases. The pressure sensitive resistor 3 has resistance characteristics such that the pressure suddenly changes at a certain pressure value p as shown in FIG. The resistor is made by mixing conductive metal powder into a polymer material such as rubber or synthetic resin, and its resistance value is S as shown in Fig. 4 with respect to the applied force.
゛This is a pressure-sensitive resistor 4 having resistance characteristics that are inversely proportional.

These two types of pressure sensitive resistors are overlapped by adhesion using an electrical adhesive, and positive and negative electrode plates 5 and 6 are attached to the outer surfaces of both pressure sensitive resistors 3 and 4, respectively.

In the horn switch made as described above, when the horn switch 2 is pressurized, the respective resistance characteristics of the pressure sensitive resistors 3 and 4 are affected, and a combined resistance characteristic as shown in FIG. 5 is obtained.

That is, the above composite resistance characteristic has no conduction at all below a certain pressure value a, becomes conductive with a resistance value greater than that pressure value a, and thereafter the resistance value decreases as the applied pressure increases, that is, as the pressure increases. In the case of continuous descent, an almost constant low resistance value is obtained above a certain pressure value.

The horn switch 2 of the present invention is set so that it can be used at pressure values from O to b in the figure.

The present invention is constructed by interposing a horn switch having such pressure-sensitive characteristics in a control circuit provided between a power source and a horn.

FIG. 2 shows one embodiment of the present invention, in which numeral 7 indicates a horn, 9 a control PNP transistor, 10 a fixed resistor, and 11 a battery.

To explain the operation of the present invention configured as above, the fifth
In the figure, the circuit is OFF while the horn switch 2 is pressed from pressure value O to pressure value a, and the horn does not issue an alarm during this period.

However, the current supplied to the horn 7 changes continuously in the pressurizing range from the pressure value a to the pressure value, and the alarm sound pressure changes accordingly, and at the same time, the vibration frequency of the horn also changes. .

Therefore, it is possible to obtain an alarm device that can change the volume and tone, from a small low sound to a large high sound, depending on the magnitude of the pressure on the horn switch.

That is, the present invention is capable of emitting a warning with a volume and tone similar to the sense of the driver, depending on the degree of need for the horn.

In addition, according to the present invention, the switch part of the horn switch is composed of a pressure-sensitive resistor mainly made of a polymer material, so it is possible to provide a horn switch for a steering wheel that is simple in structure, inexpensive, and durable. There is.

Furthermore, while the conventional horn switch was a stroke type, the proposed horn switch is more powerful than a pressure-sensitive resistor, so it can respond instantly even in the event of an emergency warning, making it a safer and better horn for steering wheels. It has the effect of providing a switch.

In the above embodiment, in the horn switch, the electrode plates 5 and 6 are provided on the outer surfaces of the pressure sensitive resistors 3 and 4, respectively, but if necessary, one of the pressure sensitive resistors 3 and 6 may be provided on the outer surface of the pressure sensitive resistors 3 and 4, as shown in FIG. A comb electrode 50 is provided on the outer surface of the piezoresistor, for example, the pressure-sensitive resistor 4, so as to be connected to both electrode terminals (+, -), respectively.
．． 60 may be adopted.

Furthermore, the control circuit shown in FIG. 2 is provided to facilitate the explanation of the present invention, and it goes without saying that various control circuits may be applied.

In particular, by combining it with an electronic horn consisting of an oscillator, amplifier, horn, etc., it is possible to better adjust the volume and tone of the alarm sound.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a steering horn switch according to an embodiment of the present invention, Fig. 2 is an alarm control circuit diagram showing an enlarged cross-section of the main part of the horn switch, and Figs. 3 and 4 show each sensor. FIG. 5 is a diagram of the resistance characteristic curves of the piezoresistors 3 and 4, and FIG. 5 is a diagram of the combined resistance characteristic curves of both the piezoresistors 3 and 4. FIG. 6 is an enlarged cross section showing the main parts of another embodiment of the present invention. It is a diagram. 1; Steering wheel, 2; Horn switch, 3;
Pressure-sensitive resistor mixed with graphite powder, 4; Pressure-sensitive resistor mixed with metal powder, 5, 6: Electrode plate, 7: Horn, 8: Control circuit.

Claims (1)

[Scope of utility model registration request] Two types of pressure-sensitive resistors are placed on the steering wheel and have different characteristics in pressure force and electrical resistance, and a horn switch is installed on the upper and lower surfaces or either of the upper and lower surfaces of the pressure-sensitive resistors to connect the power source and the horn. A horn switch for a steering wheel, characterized in that the horn switch is interposed in a control circuit provided between the horn switches, and is capable of adjusting the volume and tone of a warning sound from a horn.