JP3100554B2 - Shock sensitive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact sensing device that senses an impact when an object approaches and collides and generates a spark discharge.

[0002]

2. Description of the Related Art Conventionally, as a device for generating a spark discharge by an impact, there are an ignition device for a gas stove using a piezoelectric element and a gas lighter using a piezoelectric element. As shown in the configuration diagram of FIG. 4, the impact applying iron core 42 suppressed by the coil spring 41 pops out by operating the lever, and applies an impact to the piezoelectric element 43. At this time, the voltage generated by the element is discharged by the spark discharge unit 44,
The combustible material supplied from the pilot flame supply port 45 ignites. The feature of this device is that a spark discharge is generated by operating the lever,
It is similar to the present invention when considering the collision of an object instead of operating the lever. However, in this method, when the lever is moved by some kind of shock, ignition is induced even when it is unnecessary. When the collision is replaced with the collision of an object, a spark is generated by any collision because the piezoelectric element 43 and the spark discharge section 44 are arranged in series. That is, a threshold value that can be selected according to the strength of the collision is required, and it is safe to perform a spark discharge with a certain or more collision force.

[0003] Separately, there is an airbag system in an automobile that induces inflation of a bag by detecting a collision. As an example of this, Japanese Patent Publication No. 57-11019 discloses a method as shown in FIG. In this case, the collision is sensed by the magnetic sensing electrode 51 made of a magnetic material being peeled off from the magnet 55 by the collision of a force equal to or greater than a certain value, and
A circuit is formed by making contact with 7, and the bag is inflated by electric means. Furthermore, Japanese Unexamined Patent Publication No.
In Japanese Patent Application Laid-Open No. 6-90746, a switch 61 in the circuit shown in FIG. 6 is actuated by a certain force applied to a bumper, and a monitor current circuit flowing via a resistor 62 becomes a large current at once, and a failure diagnosis circuit is provided. At the same time as the determination by the input amplifier 63, the activating means 64 activates the occupant restraint device.

The former is a mechanical sensing device, and the latter uses an electric circuit, but the switch is a mechanical device. In principle, the former constitutes an electric circuit, and has a structure in which a switch is mechanically turned on by an impact. The electric circuit always requires a power supply so that the switch can supply electricity. In the latter case, similarly, a minute current is constantly flowing through the circuit via the resistor 62, and the power supply is always working.

As described above, there are various disclosures of means for using the collision of an object as an electric contact. However, if a monitoring current is always loaded as an electric circuit, the reliability is naturally improved. It is. Therefore, these methods require a power supply and require maintenance of the power supply.

FIG. 7 will be described as an example closer to the use of the present invention. The impact detected by the piezoelectric element 71 is subjected to signal processing by a voltage comparison circuit 72. A reference voltage for comparison is loaded on the voltage comparison circuit. If the applied impact is equal to or greater than the threshold value, the thyristor 73 is turned on, the electric charge stored in the capacitor 74 is caused to flow through the heat generating resistor 75, and discharged, thereby activating an actuator not described by the generated Joule heat. It is. The feature of this method is that the magnitude of the impact can be selected, that is, the threshold value can be adjusted because the voltage comparison circuit 72 is provided. In addition, by changing the capacitance of the capacitor 74, the discharge can be performed. You can adjust the amount. However, having the voltage comparison circuit 72 complicates the circuit.

[0007]

As described above, there are many means for receiving an impact, sensing the impact, and discharging or generating heat. However, the simplest device using a piezoelectric element is a gas lighter. It is like. However, if an impact is felt for some reason, ignition may occur at an unnecessary time, and the reliability is not high. Also, if you increase its reliability,
A complicated device like an airbag system and a power supply for monitoring are required, and a circuit as shown in FIG. 7 must be used to set a threshold value. High reliability and
It is another object of the present invention to provide a means for generating a discharge against an impact with a simple circuit.

[0008]

According to the present invention, an electric resistor and a piezoelectric element are electrically connected in parallel, and a piezoelectric element and a spark discharge section are electrically connected in series. Is to provide a shock sensitive device characterized by being formed so that it can be disconnected from external shocks, the circuit is very simple, and therefore high reliability is ensured. is there. Specifically, the electric resistor is formed integrally with a structure having an insulating property, and the structure and the resistor are located closer to the shocking object than the piezoelectric body via the insulator. I do. The electric resistor is preferably formed of a film-like material such as a thick film or a thin film. It is more preferable that the structure having an insulating property is composed of a simple substance or a composite of ceramic. According to the above configuration, the electrical configuration is very simple and the structure is also simple,
Nevertheless, the reliability of the discharge against impact is very high. In addition, the present invention does not require a power supply to operate the circuit, so that maintenance is easy and life is excellent.

[0009]

FIG. 1 shows the configuration of the present invention. Piezoelectric body 1 and electric resistor 2 are electrically arranged in parallel, and spark discharge section 3 is arranged in series with piezoelectric body 1. The spark discharge section 3 is an example using a needle-shaped discharge body having a gap between electrodes of 5 mm. According to the present invention, when an object approaches and collides, the impact is sensed and the piezoelectric body 1 generates a voltage. When the voltage does not exceed a threshold value, the piezoelectric body 1 Since the electric resistance of the resistor 2 is sufficiently small, the current generated in the piezoelectric body 1 is grounded via the electric resistor 2. When the piezoelectric body 1 generates a voltage equal to or higher than the threshold value, the electric resistor 2 is disconnected and cannot be discharged through the electric resistor 2, so that a current flows through the spark discharge section 3 to generate a spark, The spark is used to drive the system (not shown).

More specifically, the configuration is as shown in FIG. There is a structure 23 having an insulating property with respect to the approaching object 21, and a film-like electric resistor 24 is formed integrally with the structure on the side opposite to the approaching object, and these are interposed through the insulator 25. To the piezoelectric body 22 sandwiched between the electrodes 27 and 28,
Further, it is fixed to the support substrate 29. The electric circuit at this time forms the circuit shown in FIG. 1 and reaches the spark discharge unit 30 via the lead wire 31. A system started by the spark continues inside the spark discharge part, but is omitted.
Examples of such a system include an airbag device and a seatbelt pretensioner, but any system that operates by sparks may be used.

FIG. 3 is a schematic diagram showing a state at the time when an object is subjected to an impact. As shown in FIG.
The electric resistor 24
Is disconnected by an impact, a spark is generated without being generated by the piezoelectric body 22 and discharged to the ground. Incidentally, when the structure having the insulating property is destroyed in this manner, the electric resistor may come into contact with the electrode, and more preferably, on the electric resistor laminated on the surface of the structure, It is preferable to provide an insulating sheet (32 in FIG. 2).

In FIG. 2, a structure 23 having an insulating property is shown.
May have elasticity due to the collision of an object,
Those that break on impact are preferred. If the impact force is small, a wooden board can be used, but if the impact force threshold value is to be large, ceramic is good, the ceramic may be a simple substance, and other materials, such as those reinforced with fiber, the type of ceramic Changed and laminated, metal sandwiched, etc.
Various thicknesses and strengths can be selected according to the threshold value. A reinforced plastic containing a large amount of ceramic powder may be used. Ceramics or their composites have insulating properties and poor ductility, so they can be reliably broken by an impact equal to or higher than a threshold value, and therefore, a reliable disconnection of electric resistance can be generated. Electric resistor 2 integrated with this structure
As for No. 4, a sheet-like material can be bonded to the structure, but a method of coating a ceramic plate or vapor deposition can also be used. The resistance value is appropriately selected according to the electromotive force of the piezoelectric body 22 to be used. By using the film-shaped resistor in this way, the assemblability of the components shown in FIG. 2 is excellent, and since the insulating structure is formed on the insulating structure, a breakage of the electric resistance occurs due to the destruction of the insulating structure. Can be done.

The piezoelectric element 22 uses a piezoelectric element. Although it depends on the required impact value, a device such as a piezoelectric ignition element used for an ignition device used in household gas appliances can be used sufficiently.

The electrodes 27 and 28 are opposed to each other with the piezoelectric body 22 interposed therebetween. However, it is necessary to use a good conductor such as a copper plate because the piezoelectric body 22 needs to flow the electric power generated by the impact to the spark discharge portion 30 at a stretch. Since breakage due to impact causes loss of conductivity, a material having excellent ductility and ductility is preferable. Further, the lead wire 31 can be appropriately selected such as a printed wiring, a wire, and a flexible printed circuit.
As in the case of 8, in the sense of preventing breakage upon impact, the use of a wire is preferable because its reliability is improved. Support substrate 29
Breaks if the impact is large, but at least the piezoelectric body 2
2 is generated, and as a result, it is necessary to be destroyed after being discharged in the spark discharge section 30. Therefore, a material having a higher strength than the structure 23 having insulating properties should be used. Further, in view of the positional relationship with the spark discharge portion 30, a material having electric insulation is preferable,
It is preferable to use a material such as P (fiber reinforced plastic) and FRC (fiber reinforced ceramic).

In an embodiment of the present invention, as shown in FIG. 3, when an approaching object hits the shock sensitive device according to the present invention with a certain impact or more, the structure is destroyed, and further the electric resistor is destroyed. The voltage generated by the compression of the piezoelectric body is discharged at the spark discharge section via the conductor and the lead wire. The higher the speed of the approaching object, the sooner it discharges and the more the piezoelectric body is destroyed, which makes it particularly responsive to other prior arts. Therefore, a particularly good point of the present invention is that when an approaching object collides, the impact force is represented by kinetic energy,
It is more effective for high-speed low-mass objects than low-speed high-mass ones.

Further, as in the embodiment (FIG. 2) of the present invention, the piezoelectric body 22 may be of several mm in size as used in a commercially available ignition device for a gas stove. And it is also cheap.

[0017]

As described above, the present invention is a device which can be manufactured inexpensively and compactly as a device which discharges by an impact due to the collision of an approaching object, and which is sensitive only to a certain impact force or more. It has the advantages of high reliability and easy transport because no power supply is required. Above all, it has excellent characteristics of instantaneous response to impact.

[Brief description of the drawings]

FIG. 1 shows a configuration of the present invention.

FIG. 2 shows a specific embodiment of the present invention.

FIG. 3 is a schematic diagram when an impact of an object is received in the embodiment of FIG. 2;

FIG. 4 is a configuration diagram of a prior art gas stove ignition device.

FIG. 5 shows a wiring diagram of a prior art airbag sensor.

FIG. 6 is another example of a prior art airbag sensor.

FIG. 7 shows a prior art configuration of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piezoelectric body 2 ... Electric resistor 3 ... Spark discharge part 21 ... Approaching object 22 ... Piezoelectric body 23 ... Insulating structure 24 ... Electric resistor 25, 26 ... insulator 27, 28 ... electrode 29 ... support substrate 30 ... spark discharge part 31 ... lead wire 32 ... insulating sheet 41 ... coil spring 42 ... impact Applied iron core 43 ... Piezoelectric element 44 ... Spark discharge part 45 ... Spipit supply port 51 ... Magnetic sensing electrode 55 ... Magnet 57 ... Electric contact 61 ... Switch 62 ... resistor 63 ... input amplifier of failure diagnosis circuit 64 ... start-up means 65 ... power supply 71 ... piezoelectric element 72 ... voltage comparison circuit 73 ... thyristor 74 ... capacitor 75 ... Heat resistance

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidetoshi Saito 1-1-1, Konokita, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor, Masahiro Kume 1-chome, Koyo-Kita, Itami-shi, Hyogo No. 1-1 In the Itami Works of Sumitomo Electric Industries, Ltd. (56) References Hikaru 4-126172 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23Q 2/28 122 F42C 11/02 G01P 15/00

Claims (4)

(57) [Claims] 1. An electric resistor and a piezoelectric body are electrically connected in parallel, and a piezoelectric body and a spark discharge section are electrically connected in series.
An impact sensing device characterized by being formed so that disconnection is possible. 2. The method according to claim 1, wherein the resistor is formed integrally with a structure having an insulating property, and the structure and the resistor are located closer to the impacting object than the piezoelectric body via the insulator. The impact sensitive device according to claim 1, wherein 3. The impact responsive device according to claim 1, wherein the electric resistor is formed of a film-like material and is formed on a structure having an insulating property. 4. The impact responsive device according to claim 2, wherein the insulating structure is composed of a single ceramic or a composite thereof.