JPS60244863A - Impact detector - Google Patents

Abstract

PURPOSE:To easily detect the direction and force of an impact by providing a mass body in the hollow part of a hollow housing and also arranging plural pressure sensors at specific positions on the internal surfaces so that they can contact the surface, and detecting the impulsive force electrically. CONSTITUTION:The hollow housing 10 is a regular hexahedron consisting of six stainless plates, and a piezoelectric sheeet 11 as a pressure sensor is stuck on internal surfaces. A steel ball 12 is provided as the mass body which contacts piezoelectric sheets 11 on the respective internal surfaces and a lead wire 13 for outputting a detected impulsive force as an electric signal is led out of each piezoelectric sheet 11. The piezoelectric sheet 11 is composed of piezoelectric rubber 15 and conductive rubber sheets 16 and 15 provided on both surfaces of the rubber 15. The piezoelectric sheet 11 is covered with an insulating film 18 after a lead wire 13 for outputting a detection signal is connected to the conductive rubber sheet 16 formed on surface of the piezoelectric rubber 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to an impact detector for detecting impact force and impact direction.

[Prior art] Conventionally, for example, when a vehicle rear-ends or collides, it detects the impact and fastens the seat belt to protect the occupants, or activates the brakes to prevent multiple accidents. A control device has been considered.

By the way, as shown in FIG. 11, for example, a shock detector used in such a device includes a weight 1 having a function of a moving contact, and a fixture made of a magnet, a spring, etc. that fixes the weight 1 with a predetermined force. 2, and in the event of an impact, the &! 1 leaves the fixture 2, the weight 1 comes into contact with the contact point 3, and the impact is detected using a mechanical impact detector or, for example, a strain meter, etc., to detect the acceleration caused by the impact and process it electrically. For example, electronic impact detectors such as It was necessary to install an impact detector in the vehicle, and multiple impact detectors had to be used.

In addition, in the above-mentioned mechanical impact detector, the impact that can be detected is determined by the force that fixes the weight 1 of the fixture 2, so if the same structure is used, the impact force to be detected cannot be controlled, and the impact force It was not possible to obtain a corresponding detection signal.

[Objective of the Invention] Therefore, the present invention provides an impact detector configured such that a single detector can detect impacts in a plurality of directions, and the detection signal has a value corresponding to the impact force. The purpose of this invention is to enable the direction and force of impact to be easily detected without the need for multiple detectors.

[Configuration of the Invention] The configuration of the present invention to achieve the above object includes: a hollow housing; a mass body provided in a hollow portion of the hollow housing; and abutting with the mass body at a predetermined position on the inner surface of the hollow housing. A plurality of pressure sensors are provided to electrically detect the pressing force of the mass body on the inner surface of the hollow housing.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 11 is a configuration diagram of a regular hexahedral impact detector according to a first embodiment of the present invention, with one side of the hollow housing 10, which is formed in a regular hexahedral shape, removed to facilitate understanding of its internal structure. It shows.

The hollow housing 10 is formed into a regular hexahedron using six stainless steel plates, and a piezoelectric sheet 11 (described later) as the pressure sensor is provided on the inner surface of each stainless steel plate.
is attached. In addition, a steel ball 12 is provided in the hollow part of the hollow housing 10 as the mass body that can come into contact with the piezoelectric sheets on each inner surface. A lead wire 13 is drawn out for outputting the force of the ball pressing the piezoelectric sheet to the outside as an electric signal.

Next, FIG. 2 shows a sectional view showing a state in which the piezoelectric sheet 11 is attached to one surface of the hollow housing 10, and the structure of the piezoelectric sheet 11 and its attachment to the hollow housing 10 will be explained.

As shown in the figure, the piezoelectric sheet 11 consists of a piezoelectric rubber 15 and conductive rubbers 16 and 17 provided on both sides of the piezoelectric rubber 15. The manufacturing method begins with 3a TiOa as the piezoelectric rubber 15.
, PZTlPb Ti Oa and other ferroelectric ceramic powders are mixed with raw rubber that has been kneaded at about 40°C, and after being processed into a sheet by repeated heating and mixing, both sides of the sheet contain a large amount of carbon, which will become the conductive rubbers 16 and 17. The conductive rubber sheets are stacked together and oil is poured over them to form rubber. Thereafter, a high voltage is applied between the conductive rubbers 16 and 17 to polarize the piezoelectric rubber 15, thereby obtaining the piezoelectric sheet 11.

Next, in order to attach this piezoelectric sheet 11 to the hollow housing 10, first the piezoelectric rubber 15 of the piezoelectric sheet 11 created above is attached.
After a lead wire 13 for outputting a detection signal to the outside is connected to the conductive rubber 16 formed on one side of the conductive rubber 16, an insulating resin film 18 is formed by applying, for example, a polyimide resin. Conductive rubber 1 formed on the other side of one piezoelectric rubber 15
An adhesive 19 made of a low-temperature adhesive conductive paste such as a silver paste containing an epoxy resin is applied to 7, and the adhesive 19 is brought into contact with the inner surface of the hollow housing 10 and bonded by heating and drying.

In the impact detector of this embodiment having the above-described configuration, when the impact detector is fixed and an impact is applied in the direction of the arrow, as shown in FIG. 1
2 moves in the direction of arrow B with respect to the hollow housing 10 due to inertial force, presses the piezoelectric sheet 11a, and creates a gap between the lead wire 13a drawn out from the piezoelectric sheet 11a and the hollow housing 10 according to the pressing force. This will result in a voltage being generated. Therefore, the impact detector of this embodiment can not only detect impacts in six directions: top/bottom, left/right, front/rear, but also detect the impact force, and this impact detector can be used in vehicles. If there is one detector in front of the vehicle,
It is possible to detect collisions in the rear, left, and right directions, and it is now possible to precisely control the brakes or steering direction according to the direction and impact force, as well as detect vibrations from the road, falling objects, etc. It is also possible to detect impacts from above and below the vehicle, and by controlling the shock absorber, the impact force can be reduced by controlling the shock absorber, improving vehicle driving performance and safety. You will be able to improve your sexuality.

Here, in this embodiment, the steel balls 12 of the piezoelectric sheet 11
A resin film 18 is formed on the surface of the conductive rubber 16 on the side that comes into contact with the steel ball 12 to insulate it from the steel ball 12. This is because the conductive steel ball 12 is used as the mass body, and for example, If a mass body made of plastic or the like is used, or the surface of the steel ball 12 is covered with resin, it is not necessary to form the resin 118 on the surface of the conductive rubber 16.

In other words, it is only necessary to insulate the conductive rubber 16 of each piezoelectric sheet 11 provided on the inner surface of the hollow housing 10. Further, in this embodiment, a conductive adhesive 19 is used to attach the piezoelectric sheet 11 to the hollow housing 10, which allows the voltage output from the piezoelectric sheet 11 to be connected to the lead wire 1. This is because a lead wire is attached to the conductive rubber 17 in the same way as the conductive rubber 16, and the output voltage from the piezoelectric sheet 11 is detected by this lead wire and the lead wire 13. In this way, an insulating adhesive can be used as the adhesive 19.

Next, the impact detector of this embodiment as described above was prepared with dimensions as shown in Table 1 below, and the peak value of the output voltage generated from the piezoelectric sheet was measured when an impact of a predetermined acceleration was applied. As a result of conducting an impact test, the measurement results shown in FIG. 4 were obtained.

Table 1 As shown in the figure, when the acceleration is 2G to 12G, the output voltage changes proportionally. It can be seen that not only the direction can be detected, but also the impact force in the case of an impact with an acceleration (or deceleration) of 2G to 12G.

Next, the fifth embodiment shows an impact detector according to a second embodiment of the present invention.

Similarly to FIG. 1 in the first embodiment, FIG. 5 also shows the hollow housing with one side removed to facilitate understanding of its internal structure.

As is clear from the figure, in the impact detector of this example,
Its shape is a regular hexahedron similar to the first embodiment described above, but the hollow housing includes a frame portion 21 made of stainless steel that forms the edge portion of the regular hexahedron, and a frame portion 21 formed of stainless steel.
The diaphragm 22 is made up of six thin stainless steel plates that are fitted and fixed from the inside. A piezoelectric sheet 23 is attached to the inner surface of each diaphragm 22 as in the first embodiment, and the steel ball 24 provided in the hollow portion of the hollow housing is configured to come into contact with each piezoelectric sheet 23.

Here, the structure of the piezoelectric sheet 23 of this embodiment is as shown in the enlarged cross-sectional view of part C in FIG. 5 shown in FIG. So-called bimorph 4, which is sequentially layered with rubber 35
It is said to be F4311. This piezoelectric sheet 23 is made by first inserting piezoelectric rubbers 32 and 34, which are made into sheets in the same way as the piezoelectric rubber 15 of the first embodiment, into the conductive rubber 1.
Conductive rubber 31 made into a sheet like 6 and 17
．． 33 and 34, and after sequentially stacking them to form an integral body as described above, oil is poured over them to form a rubber, and a high voltage is applied between the conductive rubbers 31 and 35, which will serve as electrodes, and the conductive rubber 33, respectively. It is created by polarizing in the direction of arrow E shown in FIG.

Also, the conductive rubber 3 of the piezoelectric sheet 23 produced as described above
A lead wire 36 shown in FIG. 5 is connected to the lead wire 1, and a resin film 37 for maintaining electrical insulation from the steel ball 24 is formed on the upper surface thereof as in the first embodiment. On the other hand, the conductive rubber 35 of the pressure sheet 23 is adhered to the diaphragm 22 using a conductive adhesive 38, as in the first embodiment.

Next, the frame portion 21 forms the ridge portion of the regular hexahedral hollow housing as described above, and the center portion of the diaphragm 22 is exposed to the outside as shown in FIG. The diaphragm 22 is made up of six stainless steel plates 42 in which holes 41 are drilled so that the exposed portions thereof can protrude to the outside due to the pressing force of the steel ball 24 against the inner surface of the diaphragm 22 at the time of I# strike, and the diaphragm 22 are bonded and fixed to each stainless steel plate 42 of this frame portion 21, for example, by plasma welding or the like.

The impact detector of this embodiment with the above configuration is shown in Table 2 below.
A piezoelectric sheet was prepared with the dimensions shown in , and the peak value of the output voltage generated from the piezoelectric sheet when an impact of a predetermined acceleration was applied was measured in the same manner as in the first embodiment. The results are shown in the graph of FIG.

Table 2 As shown in Figure 8, in the shock detector of this example made with the above dimensions, the output voltage changes proportionally when the acceleration is OG to 6G, and the output voltage value is as shown in Figure 4. This value is larger than the voltage value obtained by the impact detector of the first embodiment shown in FIG. Therefore, as in this embodiment, if the piezoelectric sheet for detecting impact is made to have a bimorph structure, and the piezoelectric sheet is easily distorted by the diaphragm and is easily suppressed by the steel ball, it is possible to reduce the impact without increasing the dimensions of each part. It was found that accurate detection was possible.

In each of the above embodiments, the shape of the hollow housing is a regular hexahedron, and the impact directions that can be detected are six directions: front/back, top/bottom, left/right. Any housing may be used as long as it has a hollow part; for example, a regular octahedral housing can detect impacts in eight directions, and a regular dodecahedral housing can detect impacts in 12 directions. Alternatively, the hollow housing may have a spherical shape, and a pressure sensor such as a piezoelectric sheet for detecting pressure may be provided at a predetermined position of a spherical mass body provided in the hollow part, and the detection signal may be received from each sensor. In this case, it becomes possible to detect impacts in a plurality of desired directions.

Next, the shape of the mass body provided in the hollow part of the hollow housing may be a polyhedron, and depending on the shape of this mass body, the hollow housing may be a simple polyhedron (not a regular polyhedron).

Furthermore, although piezoelectric rubber is used as the pressure sensor in the above embodiment, any commonly used pressure sensor may be used, such as a semiconductor sensor made of silicon, for example. In this case, since each sensor uses a different pressure detection method such as changing resistance or generating electromotive force, it is necessary to provide a detection signal processing device for each sensor.

[Application example] As explained above, according to the impact detector of each of the above embodiments, when an impact is received, the steel balls in the hollow housing press the piezoelectric sheet to generate a voltage, and the direction of the impact and its Now, as an application example of the present invention, a processing device that processes a detection signal from an impact detector that generates a voltage in response to an impact as in the above embodiment will be described.

FIG. 9 is a block diagram showing the device. A detection signal from an impact detector 51 is input to a peak voltage holding circuit 52, and its peak voltage is output. The peak voltage output from this peak voltage holding circuit 52 is compared with a reference voltage from a reference voltage generation circuit 53 that generates a preset voltage in a comparison circuit 54 and output to an amplification/relay circuit 55. . When the peak voltage becomes equal to or higher than the reference voltage, power is supplied to the load by the amplification/relay circuit, and drive control is executed when the impact value is equal to or greater than a predetermined value. In the top view, 57 is a power supply circuit for supplying power to each circuit except for the shock detector 51, and this processing device simply responds to the detection signal from one pressure sensor provided in the shock detector 51. In the case of an impact detector having six pressure sensors as in the above embodiment, at least six or more devices of this kind are provided. In addition, when performing various controls according to the peak voltage of the detection signal from one pressure sensor,
Generate a plurality of reference voltages from the reference voltage generation circuit 53,
A comparator circuit 54 and an amplification/relay circuit 55 may be provided for each of these reference voltages to perform load control according to the peak voltage.

Here, a circuit example of this type of processing device is shown in FIG. 10 and briefly explained. All the circuits shown in FIG. 10 are general circuits, and the peak voltage holding circuit 52' is an operational amplifier 6.
1. Mainly composed of FET62 and diode 63,
The reference voltage generation circuit 53 outputs the peak voltage of the detection signal.
' is composed mainly of two transistors 64 and 65 and a Zener diode 66, and generates a reference voltage via a variable resistor R1. Also, the comparator circuit 54' has an operational amplifier 67
Compares the reference voltage and the peak voltage, and supplies the power supply voltage to the load 56' via the amplification/relay circuit 55' consisting of a transistor 68 and a relay 69,
drive

[Advantageous Effects of the Invention 1] As detailed above, in the impact detector of the present invention, a mass body is provided in the hollow part of the hollow housing, and a plurality of pressure sensors are provided at predetermined positions on the inner surface of the hollow housing so as to be able to come into contact with the mass body. is provided, and is configured to electrically detect the force with which the mass body presses against the hollow housing when the impact detector receives an impact. Therefore, by attaching the pressure sensor that has detected an impact among the plurality of pressure sensors, the direction of the impact can be detected depending on the position, and the force of the impact can also be detected. Therefore, if the impact detector of the present invention is used in, for example, a vehicle, and controls the brakes, seat belts, shock absorbers, etc. to protect the occupants in the event of a sudden accident such as a collision, safety can be improved. You will be able to improve your sexuality.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention.
2 is a cross-sectional view showing the structure of the piezoelectric sheet 11 and how it is attached to the housing 10.
The figure is an explanatory diagram to explain the movements of each part and their effects when subjected to an impact. Figure 4 shows measurement data when the impact detector of the first embodiment was created and an impact test was performed. The graphs and FIGS. 5 to 8 show a second embodiment of the present invention, FIG. 5 is a diagram of its overall configuration, and FIG. FIG. 7 is a perspective view illustrating the frame 21, FIG. 8 is a graph showing the impact test data of the second embodiment, similar to FIG. 4, and FIG. 10 and 10 show an example of a processing device for processing detection signals when the impact detectors of the first and second embodiments are actually used, and FIG. 9 is a block diagram thereof, and FIG. The figure is a circuit diagram, 1st
FIG. 1 is a schematic configuration diagram showing a conventional impact detector. 10...Hollow housing 11.23...Piezoelectric sheet 12.24...Steel ball 21...Frame 22...Diaphragm Agent Patent attorney Tsutomu Sadatsu et al. Fig. 1 1n Fig. 2 Fig. 3 Fig. 4 rV speed (xGm ferocious Fig. 5 Fig. 2 Fig. 8 1 mouth speed is poor (×Grr し〇F'f) Fig. 9 Fig. 10

Claims (1)

[Scope of Claims] A hollow housing; a mass body provided in a hollow portion of the hollow housing; An impact detector comprising: a plurality of pressure sensors that electrically detect pressing force on the inner surface of a housing;