JPH06235774A - Contact type sensor - Google Patents

Abstract

PURPOSE:To retain air in internal space to atmospheric pressure and to secure the insulation spacing of a contact for preventing erroneous operation by releasing the internal space of a sensor body to atmosphere via a continuity path. CONSTITUTION:Lead wires 17 and 18 which are led from the edge part of a sensor body 11 consisting of an insulation elastic body such as rubber is covered with a coating tube 20 and an air continuity path 21 consisting of a capillary is formed inside the tube 20. When a vehicle, etc., are on the sensor and crushes the body 11, both contacts 13 and 14 contact and current flows to the lead wires 17 and 18. It is detected, thus detecting the presence of the vehicle etc. In this case, when the body 11 is compressed and deformed, an internal space 12 contracts and air pressure increases. The air pressure is allowed to escape to the open air via the air continuity path 21. Then, when the load of the sensor is released and the body 11 is subjected to elastic return, the space 12 expands and the open air flows in from the path 21, the space 12 is maintained to be at the atmospheric pressure, and hence the insulation spacing between the contacts 13 and 14 is secured, thus eliminating the reduction in internal pressure due to oxygen absorption and gas transmission and preventing an unexpected short-circuiting.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is effective for use as a vehicle detection device in a toll collection system such as a toll road or a parking lot, or as a tread plate for a vehicle type identification device, and secures a space inside an insulating elastic body. Then, a pair of contacts are arranged in the insulating elastic body so as to be able to come into contact with and separate from each other through the space, and when the insulating elastic body is compressed by pressure or impact, the contacts are brought into contact with each other. The present invention relates to a contact-type sensor that detects the presence of an object.

[0002]

2. Description of the Related Art As a detection device for detecting the presence of an object,
There is known a contact-type sensor that utilizes a pair of contacts that are brought into contact with each other by the weight or contact of an object to short-circuit a current-carrying circuit. A conventional structure of this type of contact type sensor will be described with reference to FIGS. 16, 17 and 18. FIG. 16 is an external perspective view of the contact type sensor, and in the figure, reference numeral 11 is a sensor body. This sensor body 11 is
For the purpose of electrical insulation and measures against dust, moisture, etc., it is made of an insulating elastic body such as rubber and has a completely sealed structure of a rectangular cylinder. As shown in FIGS. 17 and 18, the sensor body 11 has an internal space 12 formed therein.
A pair of contacts 13 and 14 which are vertically separated are attached so as to face each other so as to be able to come into contact with and separate from each other. These pair of contacts 13, 1
4 is connected to lead wires 17 and 18 via joint portions 15 and 16 such as solder. These lead wires 17, 1
Reference numeral 8 is airtightly penetrated through the end wall of the sensor body 11 and led out to the outside.

The contact type sensor having such a structure receives the weight and pressing force of the object when the object passes over the contact type sensor or directly contacts the contact type sensor. Detect an object. That is, when an object rides on or comes into contact with the contact-type sensor, the sensor body 11 made of an insulating elastic body of the contact-type sensor is deformed by the pressing of the object, and the contacts 13 and 14 contact each other. Therefore, the lead wire 1
A current flows between 7 and 18, and the presence of an object can be known by detecting this electrical characteristic.

[0004]

However, in the above-mentioned conventional contact-type sensor, the sensor main body 11 each made of an insulating elastic body has a structure in which the internal space 12 is completely sealed, and The structure was also small in volume. Therefore, oxygen contained in the air in the internal closed space 12 is physically or chemically absorbed by a substance such as rubber which is the inner wall by long-term use (oxygen absorption). In addition, when used in an application in which pressing by an object occurs continuously, a rapid change in atmospheric pressure (rise) of the space 12 inside the sensor occurs continuously, so that air permeates elastic bodies such as rubber. Then, the phenomenon of (gas permeation) leaking to the outside also occurs. These phenomena tend to increase in proportion to the internal pressure of the sealed space 12, and as a result of such a phenomenon, the internal pressure of the contact-type sensor becomes lower than the atmospheric pressure and becomes a so-called negative pressure. Therefore, the volume of the internal space 12 is reduced, and the insulation interval between the pair of contacts 13 and 14 cannot be ensured, and the contacts 13 and 14 come close to each other, resulting in a short circuit even if no load is applied, There is a risk of malfunction.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent the air in the internal space from decreasing and to reliably secure an insulation interval between a pair of contacts to cause a malfunction. The present invention is intended to provide a contact type sensor capable of preventing the above.

[0006]

In order to achieve the above object, a first aspect of the invention is to form a space inside a sensor body made of an insulating elastic body, and to provide a pair of contact points which can be brought into contact with and separated from the space. In a contact type sensor provided so as to face each other so that the pair of contacts are brought into contact when the sensor body is forcibly deformed,

The internal space of the sensor body is opened to the atmosphere through the conducting path, and when the sensor body is pressed and the pressure in the internal space rises, this pressure is released to the outside through the conducting path. It is characterized by having done.

According to a second aspect of the present invention, the internal space of the sensor body is connected to an accumulator which keeps the pressure constant by deforming or displacing the movable wall when the pressure rises, and the sensor body presses the accumulator. When the pressure in the internal space rises due to this, this pressure is released to the accumulator.

[0009]

According to the first aspect of the invention, since the internal space of the sensor body made of the insulating elastic body is open to the atmosphere through the conducting path, when the sensor body is pressed and the pressure in the internal space rises. This pressure can be released to the outside through the conducting path, and the internal space can be maintained at a pressure equivalent to atmospheric pressure. Then, when the internal pressure decreases, the atmosphere is introduced through the conducting path, so that the decrease of the air can be prevented.

According to the second aspect of the invention, when the pressure in the internal space of the sensor body rises, this pressure is transmitted to the movable wall of the accumulator, and the movable wall deforms or displaces to escape. The internal pressure can be kept constant. Therefore, even if the physical or chemical absorption amount of oxygen by the rubber or the air permeation of the rubber occurs, the movable wall is deformed or displaced, so that the internal space can always be kept at a constant pressure.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the first embodiment shown in FIGS.

FIG. 3 is an external view of a contact type sensor to which the present invention is applied. This contact type sensor has the same basic structure as that of the conventional example shown in FIG. 16 and subsequent drawings. Are assigned the same numbers and explanations thereof are omitted.

In the case of the present embodiment, the lead wire 1 led out from the end portion of the sensor body 11 formed of an insulating elastic body.
7, 18 are covered with a jacket tube 20, and inside the jacket tube 20, as shown in FIG.
A conduction path 21 made of a thin tube other than 7, 18 is formed. One end of the conduction path 21 penetrates the end wall of the sensor body 11 and communicates with the internal space 12 inside the sensor body 11, and the other end is open to the atmosphere. Therefore, the internal space 12 of the sensor body 11 communicates with the atmosphere via the conduction path 21.

In the contact type sensor having such a configuration, when an object passes over the contact type sensor or directly contacts the contact type sensor, the sensor body 11 made of an insulating elastic body pushes the contact body. It is crushed, so that the contacts 13 and 14 contact each other. Therefore, a current flows between the lead wires 17 and 18, and the presence of an object can be detected by detecting this.

In this case, when the sensor main body 11 is compressed and deformed, the internal space 12 is compressed, so that the pressure in the internal space 12 rises. This pressure is released to the atmosphere via the conduit 21, so that the pressure in the internal space 12 can be made equal to the atmospheric pressure. Further, when the load of the sensor body 11 is released and the sensor body 11 elastically returns, the internal space 1
2 expands and the pressure drops, but in this case, the conduit 21
Atmosphere is introduced through the valve, so that the pressure in the internal space 12 can be made equal to the atmospheric pressure. Therefore, since the space 12 inside the sensor is always kept equal to the atmospheric pressure, the decrease in internal pressure due to oxygen absorption and gas permeation is eliminated, and the contact 1
The accidental short circuit of 3 and 14 is prevented.

Particularly in the case of the above embodiment, since the conducting path 21 made of a thin tube or the like is formed in the outer tube 20 which covers the lead wires 17 and 18 for transmitting the output signal, the sensor body 1
A mechanism that keeps the atmospheric pressure of the internal space 12 constant can be provided in a portion independent of 1, and the performance of the sensor itself is not impaired, and it is not necessary to add an extra cable. That is, the attachability and the detachability can be maintained.

Therefore, the function and size of the sensor, the mountability,
The maintainability remains the same as before, and it is possible to prevent a decrease in the atmospheric pressure of the internal space 12 of the sensor and prevent a short circuit of the contacts 13 and 14 caused by this.

Next, a second embodiment shown in FIGS. 5 to 9 will be described. This embodiment shows an example applied to a vehicle detection device and a vehicle type identification device of a toll collection system on a toll road or a parking lot. FIG. 5 is a schematic view showing the outer appearance of the vehicle detection device, in which reference numeral 50 is a passing vehicle. The passing vehicle 50 advances along the vehicle approach path 51 in the direction of arrow A. Reference numeral 52 denotes a vehicle detection device, which is embedded in the vehicle separators 53 and 54 facing each other with the vehicle entrance 51 interposed therebetween and the road surface of the vehicle entrance 51 located immediately below the optical axes of the vehicle separators 53 and 54. It is composed of the tread 55 which is formed.

FIG. 6, FIG. 7 and FIG. 8 are an external view and a vertical sectional view of the tread 55. In these drawings, reference numeral 61 is a tread body, which is formed of an elastic body such as rubber. In this tread plate body 61, for example, four hollow portions 6
2a, 62b, 62c, 62d are provided, and contact type sensors 63a, 63 are provided in these cavities, respectively.
b, 63c and 63d are inserted. In addition, 64 is an insert board | substrate which supports the said contact-type sensor, and is a rigid body structure.

Each contact type sensor 63a, 63b, 63
As in the first embodiment, c and 63d form a space 66 with a narrow interval inside the sensor body 65 made of an insulating elastic body, and the inner space 66 of the sensor body 65 has an inner wall 66a. Contacts 67a and 67b are attached so as to face each other vertically. These contact points 67a and 67b are coupled parts 68a and 68.
It is joined to the lead wires 69a and 69b via b.
These lead wires 69a and 69b are led out from the end portion of the sensor body 65, and a thin tube forming a ventilation passage 70 is provided in this lead portion. The conduction path 70 is electrically connected to the internal space 66 of the sensor body 65.

Then, the contact type sensors 63a, 63
A head portion 61a is formed at an end portion of the tread body 61 having b, 63c and 63d therein, and a flexible tube 75 is led out from the head portion 61a. Inside the tube 75, the sensors 63a, 63b, 63c, 63 are provided.
The lead wire led from d is inserted. A cross-sectional view of this tube 75 is shown in FIG. 9, and inside this tube 75, other lead wires 71 are provided together with the lead wires 69 a, 69 b.
a, 71b, 72a, 72b, 73a, 73b are inserted. That is, four contact sensors are inserted into the tread 55, each sensor has a pair of contacts, and two lead wires are connected to each other. There are book leads.

A ventilation thin tube 76 is inserted through the tube 75, and a communication passage 77 is formed in the thin tube 76. One end of the communication passage 77 has the head 6 of the tread.
Each of the sensors 63a, 63b, 63 is branched in 1a.
While being communicated with the conduction paths 70 ...
The other end is open to the atmosphere.

The tread 55 having such a structure is used for the passing vehicle 5
When 0 passes over the tread 55, the tread body 61 made of rubber or the like is crushed and deformed, and the contact sensors 63a, 63b, 63c, 63d housed therein are compressed. In each sensor, the sensor main body 65 made of an insulating elastic body is crushed, whereby both contacts 67a, 67 are formed.
b contact each other. Therefore, the lead wires 69a and 69b
An electric current flows through the vehicle, and the passage of the vehicle can be detected by detecting the electric current.

When the sensor main body 65 is compressed and deformed, the pressure in the internal space 66 rises, but this pressure is released to the atmosphere via the communication passage 70 and the communication passage 77 in the tube 75, so that The pressure in the internal space 66 becomes equal to the atmospheric pressure. When the sensor body 65 elastically returns,
The internal space 66 expands and the pressure decreases, but in this case, the atmosphere is introduced through the communication passage 77 and the conduction passage 70,
Therefore, the pressure in the internal space 66 is made equal to the atmospheric pressure. Therefore, the space 66 inside the sensor can always be kept equal to the atmospheric pressure, the decrease in the internal pressure due to oxygen absorption and gas permeation is eliminated, and accidental short circuit of the contacts 67a and 67b is prevented.

Although not shown, the vehicle type discriminating apparatus has a configuration in which several types of sensors are added to the configuration of the vehicle detecting apparatus 52, and the tread used in the vehicle type discriminating apparatus is a vehicle detecting device. Although it has a highly accurate contact sensor as compared with the tread used in the device, its basic structure is the same as that of the vehicle detection device 52. Therefore, if the above configuration is adopted, the present invention can be applied to the vehicle type identification device.

In the first and second embodiments described above, the case where the conducting paths 21 and 70 are opened to the atmosphere has been described. However, if it is desired to prevent dust and dust from entering the atmosphere, these conducting paths 21 and 70 can be opened.
The 70 may be connected to a pressure accumulator that includes a closed space having a large volume that is isolated from the atmosphere, an accumulator, or the like.

Next, a third embodiment of the present invention will be described. The third embodiment corresponds to the second invention,
FIG. 10 is an external view of the contact type sensor, and FIG. 11 is a cross-sectional view of the end portion. In the figure, reference numeral 11 is a sensor body similar to the sensor body shown in FIG. 14, and this sensor body 11 is made of an insulating elastic body such as rubber and has a space 12 formed therein. A pair of contact points 13 and 14 are attached to the inner wall of the space 12 so as to be vertically opposed to each other, and the pair of contact points 13 and 14 are joined to each other through a joint portion 15, 1 such as solder.
It is connected to lead wires 17 and 18 via 6. These lead wires 17 and 18 extend through the end wall of the sensor body 11 in an airtight manner and are led out to the outside.

The above structure may be similar to that of the conventional sensor shown in FIG. An accumulator 111 is integrally formed at the other end of the sensor body 11. The accumulator 111 is configured by partitioning an air chamber 113 and an atmosphere open chamber 114 by a diaphragm 112 corresponding to a movable wall, and the air chamber 113 communicates with the internal space 12 via a passage 115. The atmosphere opening chamber 114 communicates with the atmosphere via a ventilation path 116.

In the case of such a structure, when an object passes over the contact type sensor or directly contacts the contact type sensor, the sensor body 11 made of an insulating elastic body is crushed, As a result, the contacts 13 and 14 come into contact with each other. Therefore, a current flows between the lead wires 17 and 18, and the presence of an object can be known by detecting this.

When the sensor body 11 is compressed and deformed, the internal space 12 is compressed and the pressure in the internal space 12 rises. This pressure is transmitted to the air chamber 113 via the throttle passage 115.
Pressure rises. The air in the air chamber 113 pushes the diaphragm 112 to bend it, so that the atmosphere opening chamber 114
Press the air of. Therefore, the air in the atmosphere open chamber 114 is released to the atmosphere through the ventilation path 116. That is, when the pressure in the internal space 12 of the sensor body 11 rises, the air in the atmosphere open chamber 114 is pushed out by the action of the diaphragm 112, so that the pressure in the internal space 12 is prevented from rising.

When the load of the sensor body 11 is removed and the sensor body 11 elastically returns, the internal space 12 expands and the pressure drops. In this case, the diaphragm 112 is used.
Elastically returns, and the atmosphere is introduced into the atmosphere opening chamber 114 through the ventilation path 116 to increase the pressure in the air chamber 113 and return the pressure in the internal space 12 to the atmospheric pressure.

Therefore, since the space 12 inside the sensor is always kept equal to the atmospheric pressure, the decrease in internal pressure due to oxygen absorption and gas permeation is eliminated, and accidental short circuit of the contacts 13 and 14 is prevented. Further, the internal space 12 is the diaphragm 11
Since it is separated from the atmosphere by 2, the invasion of dust, dust, water, etc. is prevented.

A fourth embodiment of the present invention will be described with reference to FIGS. This embodiment is an example applied to the tread 55 of the vehicle detection device 52 described above, and the same parts as those shown in FIGS. 6 to 8 use the same reference numbers, but the reference numeral 61 indicates the tread body, It is formed of an elastic body such as rubber. For example, four hollow portions 62a, 62b, 62c, 62d are provided in the step board main body 61, and contact type sensors 63a, 63b, 63c, 63d are inserted and attached to these hollow portions, respectively.
Each contact type sensor 63a, 63b, 63c, 63d is
Similarly to the case of the first embodiment, narrow spaces 66 are formed inside the sensor body 65 made of an insulating elastic body,
Contacts 67a and 67b are attached to the inner wall of the internal space 66 of the sensor body 65 so as to face each other vertically. These contacts 67a and 67b are joined to a lead wire (not shown). At the end of the sensor body 65, a through hole 80 is formed to connect the internal space 66 and the external cavity 62b. The lead wires of the sensors are bundled by the tube 75 and led out from the end of the tread body 61.

An accumulator 151 is integrally formed at the end of the step board body 61. The accumulator 151 is configured by partitioning an air chamber 153 and an atmosphere open chamber 154 with a diaphragm 152.
The air chamber 153 has passages 155a, 1 respectively.
It communicates with the hollow portions 62a, 62b, 62c, 62d of the tread main body 61 via 55b, 155c, 155d.
Since each cavity communicates with the internal space 66 of the sensor, the air chamber 153 eventually communicates with the internal space 66 of each sensor. Further, the atmosphere open chamber 154 communicates with the atmosphere via the air passages 156 and 146.

In such a structure, when the passing vehicle 50 (see FIG. 5) passes over the tread 55, the tread main body 61 made of rubber or the like is crushed and deformed, and the contact type is accommodated inside. The sensors 63a, 63b, 63c, 63d are compressed. In each sensor, the sensor main body 65 made of an insulating elastic body is crushed, whereby both contacts 67a, 6
7b contact each other. Therefore, the passage of the vehicle can be detected.

When the sensor body 65 is compressed and deformed, the pressure in the internal space 66 rises, and this pressure is passed through the passages 80 ...
2a, 62b, 62c, 62d, and the air in these cavities passes through the passages 155a, 155b, 155, respectively.
It is sent to the air chamber 153 through the c and 155d.

When the pressure in the air chamber 153 rises, the diaphragm 152 is pushed to bend it and press the air in the atmosphere open chamber 154. Therefore, the atmosphere open chamber 15
The air of No. 4 is released to the atmosphere through the air passages 156 and 156. That is, when the pressure of the internal space 66 of the sensor body 61 rises, this pressure is transmitted to the air chamber 153,
The air in the atmosphere open chamber 154 is pushed out by the action of the diaphragm 152, thus preventing the pressure in the internal space 66 from rising.

When the load of the sensor body 65 is removed and the sensor body 65 elastically returns, the internal space 66 expands and the pressure drops. In this case, the diaphragm 152 is used.
Elastically returns, the atmosphere is introduced into the atmosphere open chamber 154, the pressure of the air chamber 153 is increased, and the pressure of the internal space 66 is returned to the atmospheric pressure. Therefore, since the space 66 inside the sensor is always kept equal to the atmospheric pressure, the decrease in internal pressure due to oxygen absorption and gas permeation is eliminated, and accidental short circuit of the contacts 67a and 67b is prevented.

In the third and fourth embodiments described above,
Although the case where the diaphragms 112 and 152 are used has been described, the present invention is not limited to this, and can be implemented by using other movable walls such as bellows and pistons.

[0040]

As described above, according to the first invention,
Since the internal space is opened to the atmosphere by the conduction path, the internal space can be kept at atmospheric pressure, the internal pressure rise can be suppressed without impairing the function and performance of the conventional sensor, and oxygen absorption and gas permeation amount can be reduced. By doing so, the air amount inside the sensor can be kept constant, short-circuiting of the contacts due to a decrease in internal pressure can be prevented, and the insulation interval between the pair of contacts can be reliably ensured to prevent malfunction.

According to the second aspect of the invention, since the pressure fluctuations in the internal space are absorbed by the deformation or displacement of the movable wall, the internal space can be kept at a constant pressure, and the oxygen absorption and air permeation in the internal space of the sensor can be maintained. It is possible to prevent the decrease in the internal pressure caused by the above and prevent the short circuit of the contacts.

Oxygen absorption and air permeation tend to increase in proportion to the internal pressure, and in a frequently used sealed contact type sensor, the internal pressure rises frequently, so that the oxygen absorption and air permeation are large. However, according to the above inventions, the internal pressure rise can be suppressed, the oxygen absorption and air permeation amount can be reduced, and the air pressure inside the sensor can be kept at atmospheric pressure. Therefore, it is possible to effectively prevent the short circuit of the contact due to the decrease of the internal pressure.

[Brief description of drawings]

1 is a cross-sectional view of an end portion of the contact type sensor of FIG. 3 taken along the line I-I, showing the first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the cable tube taken along the line II-II of FIG. 1 in the same example.

FIG. 3 is an external perspective view of the contact type sensor of the embodiment.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3 in the same embodiment.

FIG. 5 is a configuration diagram of a vehicle detection device according to the second embodiment of the present invention.

FIG. 6 is an external perspective view showing the tread plate of the embodiment.

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6 in the example.

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 6 in the same example.

FIG. 9 is a sectional view taken along line IX-IX in FIG. 8 in the example.

FIG. 10 is an external perspective view of a contact type sensor showing a third embodiment of the present invention.

11 is a cross-sectional view taken along line XI-XI of FIG. 10 in the example.

FIG. 12 is an external perspective view of a tread used in a vehicle detection device according to a fourth embodiment of the present invention.

13 is a sectional view taken along line XIII-XIII in FIG. 12 in the same example.

FIG. 14 is a sectional view taken along line XIV-XIV in FIG. 12 in the same example.

FIG. 15 is a cross-sectional view of an end portion in the example.

FIG. 16 is an external perspective view of a contact-type sensor showing a conventional structure.

17 is a sectional view taken along line XVII-XVII in FIG.

18 is a sectional view taken along line XVIII-XVIII in FIG.

[Explanation of symbols]

11, 65 ... Sensor main body made of insulating elastic body 12, 66 ... Internal space of main body 13, 14, 67a, 67b ... Contact points 17, 18, 69a, 69b ... Lead wire 21, 70, 77 ... Communication passage 50 ... Passing vehicle 51 ... Vehicle approach path 52 ... Vehicle detection device 53, 54 ... Vehicle separator 55 ... Tread plate 61 ... Tread body 62a, 62b, 62c, 62d ... Cavity part 63a, 63b, 63c, 63d ... Contact type sensor 111, 151 ... Accumulator 112, 152 ... Diaphragm 115, 155 ... Passage 116, 156
… Vents.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashige Matsuda 1-1-1 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Prefecture Mitsubishi Heavy Industries Ltd. Kobe Shipyard

Claims (2)

[Claims] 1. A space is formed inside a sensor body made of an insulating elastic body, and a pair of contacts that can be brought into contact with and separated from each other are provided in the space so as to face each other. In a contact type sensor in which a pair of contacts are brought into contact with each other, the internal space of the sensor body is opened to the atmosphere through a conduction path, and when the sensor body is pressed and the pressure in the internal space rises, this pressure is applied. A contact-type sensor, characterized in that the internal space is maintained at a pressure equivalent to atmospheric pressure by allowing the gas to escape to the outside through the conduction path. 2. A space is formed inside a sensor body made of an insulating elastic body, and a pair of contact points that can be brought into contact with and separated from each other are provided in the space so as to face each other. In a contact type sensor in which a pair of contacts are contacted, the internal space of the sensor body is connected to a cumulator that keeps the pressure constant by deforming or displacing the movable wall when the pressure rises, When the sensor body is pressed and the pressure in the internal space rises, this pressure is released to the accumulator, and the movable wall of the cumulator is deformed or displaced to keep the pressure in the internal space constant. A contact-type sensor characterized in that