JPS6220108Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a treadle device that is a sensor that measures the number of axles of passing vehicles on a toll road.

On toll roads, toll fees often vary depending on the type of vehicle, such as large vehicles or regular vehicles. On the other hand, there is a recent trend toward completely unmanned toll collection operations on toll roads, and such unmanned systems must accurately identify vehicle types. In conventional systems, optical sensors detect the vehicle body, and a tread plate installed on the road surface, which is a switch for detecting the number of axles, detects the number of times the tires are pressed, and determines whether the number of axles is two or three or more. The system detects whether the vehicle is a large vehicle or a vehicle smaller than an ordinary vehicle.

For reference, Figure 1 shows an example of how treads are used on toll roads. The figure is a perspective view of a tollgate, where 1 is an island of the tollgate, 2 is a vehicle, and this vehicle 2 enters from the direction of the illustrated arrow.
Near the entrance of the lane, a light emitting part 3 and a light receiving part 4 of an optical sensor for distinguishing vehicles one by one on both sides of the lane are arranged so as to face each other.
Vehicles traveling in the lane block the light beam irradiated from the light projector 3 toward the light receiver 4, thereby separating and distinguishing the vehicles one by one. Immediately below the optical axis of this light beam, a footboard 5 is laid buried in the road surface to the full width of the lane. The treadle 5 is a switch body molded with rubber, and when it is pressed by the wheel of a passing vehicle and the switch portion closes, it detects the wheel, and the number of axles is determined from the number of times the treadle 5 detects while the light beam is interrupted. Count. 6 is an automatic toll collection machine provided on the island 1, and the toll fee determined based on the number of axles mentioned above is displayed on the display 7 of the automatic toll collection machine 6, for example.
When the driver inserts the appropriate amount into the hopper 8 of the automatic toll collection machine 6, the automatic toll collection machine 6 automatically checks this and passes the toll at the barrier installed at the exit of the tollgate. Release machine 9. Passage of a vehicle is detected by a loop coil type vehicle detector 10 installed on the road near the barrier 9, and the barrier 9 is closed.

FIG. 2 shows the cross-sectional structure of a conventionally used footboard 5. 11 is the road surface, and 12 is the main body of the footboard 5, which is entirely molded with rubber and is usually buried so as to be at the same height as the road surface 11. 1
3 is a reinforcing iron plate provided at the bottom of the main body 12, and S ₁ , S ₄ are contact bodies arranged along the traveling direction of the vehicle, and are inserted into the cavity of the main body 12. When the main body 12 is crushed under the pressure of the wheels, the contact body at that portion closes.

The structure of the contacts S ₁ to S ₄ is as shown in FIG. 3, and consists of metal plates Sa and Sb for electrodes placed above and below the rectangular cavity 14 of the main body 12, facing each other. be.

By the way, when a vehicle passes through the treadle plate 5, the pressure P is applied in a direction that flows slightly in the direction in which the wheels travel, so that the cavity 14 of the main body 12 is obliquely crushed.
For example, as shown in FIG. 4, the Sb contacts each other in sliding contact to detect the passage of a vehicle. Therefore, since the conventional footboard is operated by deformation of the main body 14 due to tread pressure, stress is concentrated on the section AA in FIG. 4, which is a factor that determines durability. Therefore, if this is reinforced, the operation sensitivity will become dull.

In addition, since the dynamic load when the wheels pass flows in the direction of travel as shown in Figure 4, the electrode metal plates Sa,
When the Sb contacts, the electrode metal plates Sa and Sb come into sliding contact with each other, causing friction and generating friction powder. If the amount of friction powder increases, a short circuit will occur between the electrode metal plates Sa and Sb, resulting in false detection.

Incidentally, here, as shown in Fig. 2, a plurality of contact bodies
The reason why S ₁ and ~S ₄ are arranged in parallel along the direction of travel of the vehicle is to determine whether the wheels are moving forward or backward.As shown in the operation timing chart of the contact body in Fig. 5, the contact body S ₁ → This is because when S ₂ →S ₃ →S ₄ are closed in an orderly manner, it is determined that the vehicle is moving forward, and when the reverse is the case, it is determined that the vehicle is moving backward.

The present invention was developed in view of the above-mentioned circumstances, and is a step board device that is buried along the width of a vehicle passageway and measures the number of axles of a passing vehicle by the tread pressure of the wheels of the passing vehicle. A conductive rubber whose resistance value changes when subjected to pressure; a common electrode plate adhered to the lower surface of the conductive rubber with conductive adhesive; a plurality of narrow electrodes that extend along the longitudinal direction of the conductive rubber and are attached with a conductive adhesive; and continuity detection members provided in the wiring that connects each of the electrodes to the common electrode plate. The conductive rubber, common electrode plate, and each electrode are
It is constructed by molding rubber to cover its surroundings, and conductive rubber is used as a sensor to detect the wheel pressure, and a common electrode plate is adhered to the bottom surface of this conductive rubber with conductive adhesive. , a detection unit for detecting wheel tread pressure is provided by adhering with a conductive adhesive a plurality of electrodes extending along the longitudinal direction of the conductive rubber at a predetermined distance apart in the width direction on the upper surface of the conductive rubber with a conductive adhesive. A non-contact structure is used to prevent frictional contact between the conductive rubber and the electrode in the detection part, thereby extending the life of the sensor, and preventing deterioration of durability due to stress concentration and deformation. The purpose of the present invention is to provide a footboard device that provides a

Hereinafter, one embodiment of the present invention will be explained in Figures 6 to 8.
This will be explained with reference to the figures.

The present invention is characterized in that the conventional switch body is made of conductive rubber, and as a result, the displacement (distortion) of the switch body due to tread pressure is kept extremely small, resulting in a highly durable and simple structure.

Here, conductive rubber is a transducer whose electrical resistance changes in response to pressure stimulation, and the magnitude of the resistance change varies from an insulating state (several tens of MΩ) to a conducting state (several tens of MΩ) depending on the magnitude of the pressure. ) is a pressure-sensitive resistor with a switching function that changes rapidly up to

For example, conductive rubber manufactured by Nippon Gosei Rubber Co., Ltd. has a resistance of 10 ^-8 Ω-cm when no pressure is applied and a resistance of 10 ^-2 Ω-cm or less when conducting. In addition, it has the property that only the pressurized portion is electrically conductive. The properties of the rubber are the same as regular rubber; for example, the hardness is 70 and the density is 3.3.
g/cm ³ , tensile strength 15 Kg/cm ² , and elongation 200%.
The operating pressure varies slightly depending on the type, but the pressure is 0.1~
It becomes conductive at 3Kg/ ^cm2 .

FIG. 6 shows an example in which conductive rubber is used as a pressure switch. In the figure, PCR is conductive rubber, and P(+) and P(-) are this conductive rubber.
These are electrodes provided on the top and bottom surfaces of the PCR. E is a DC power supply, r is a variable resistor, and PC is a photocoupler. The light emitting diode D of this photocoupler PC is connected to the electrodes P(+) and P(-) through the series circuit of the variable resistor r and the DC power source E, and the electrode P(+) on the upper surface side of the conductive rubber PCR. When the conductive rubber PCR becomes conductive due to pressure from the foot, the electrodes P(+) and P(-) are short-circuited and the current from the DC power source E flows through the light emitting diode D, lighting it up.
The light receiving transistor Tr of the photocoupler PC is turned on and operates as a pressure switch. The variable resistor r is a resistor for adjusting the current flowing through the light emitting diode D, and T ₁ and T ₂ are the collector and emitter terminals of the light receiving transistor Tr.

FIG. 7 is a diagram illustrating the principle of using the pressure switch configured as described above as a step board. In the figure,
PCR is the conductive rubber mentioned above, P ₀ is this conductive rubber PCR
Common electrode plates P ₁ and P ₄ are attached to the bottom surface of the conductive rubber PCR using conductive adhesive. These electrodes P ₁ and P ₄ are used to detect the pressing state of the conductive rubber PCR at each position. E is a DC power supply, PC ₁ and _{PC 4} are photocouplers similar to those described above, and these photocouplers
PC ₁ and PC ₄ correspond to the electrodes P ₁ and P ₄ one by one, and one end of the light emitting diode of the photocoupler is connected to the electrode. Further, the other ends of the light emitting diodes are connected to the positive electrode side of the DC power supply E through variable resistors r ₁ and r ₄ respectively, and
The negative electrode side of the DC power source E is connected to the common electrode plate _P0 .

FIG. 8 shows the cross-sectional structure of the pressure sensor portion of the pressure switch, that is, the portion consisting of the conductive rubber PCR and its electrodes P ₁ , -P ₄ , and P ₀ when configured as a step board. In the figure, P ₀ is the common electrode plate that also serves as a reinforcing plate.
PCR is a conductive rubber, P ₁ to P ₄ are electrodes, and these are arranged in exactly the same manner as in the case of FIG. 7.
Then, mold rubber to cover these areas.

Next, the operation of this device having the above configuration will be explained. The pressure sensor portion shown in FIG. 8 is rectangular with such a cross section, and the pressure sensor is laid on the road surface with its longitudinal direction facing the width direction of the lane. Then, when a vehicle passes over the pressure sensor, the portion where the wheel passes receives tread pressure, and the resistance value of the conductive rubber in that portion decreases. Then, the electrode of that part of the pressure sensor and the common electrode plate P ₀ become electrically conductive. The common electrode plate P ₀ is connected to the negative electrode side of the DC power source E, and the positive electrode side of the DC power source E is connected to the photo couplers PC ₁ , ~PC ₄ via variable resistors, and photo couplers PC ₁ , ~ _{PC 4} are connected to the electrodes P ₁ and P ₄ of the corresponding pressure sensors, so the photocoupler connected to the conductive electrodes lights up its light emitting diode D and turns on the light receiving transistor Tr. The collector and emitter terminals T ₁ and T ₂ are made conductive. Therefore,
By obtaining signals from T ₁ and T ₂ of each photocoupler, it is possible to identify which position of the pressure sensor received the pedal pressure, and when a car passes, PC ₁ →
Signals can be obtained in the order of PC ₂ → PC ₃ → PC ₄ or vice versa, and detection can be performed in exactly the same way as in the conventional method.

In addition, in this device, the pressure sensor uses conductive rubber whose resistance value changes suddenly due to pressure, and the change in resistance value is used as a switching action, so there is no contact, and the electrode does not change due to frictional contact as in the past. In addition to eliminating the generation of friction particles and resulting durability deterioration such as short-circuit accidents, the degree of deformation of the conductive rubber is small, which reduces fatigue of the material due to stress concentration as explained in Figure 4, resulting in a highly durable structure. Become. Furthermore, the common electrode plate of the pressure sensor can also be used as a reinforcing board, and there is no need for a stroke between the electrodes of the pressure sensor, resulting in a thin structure, lightweight, and greatly improved installation conditions, compared to conventional models. The structure is simplified, the number of parts is reduced, and costs such as assembly man-hours can be reduced.

Furthermore, since the pressure sensor is a non-contact switch, there is no discharge of sparks, and there is no deterioration of the electrodes due to this, making it far more durable than conventional pressure sensors.

In this way, the present invention is buried along the width of a vehicle passageway, and is activated by the pressure of the wheels of passing vehicles.
In the treadle device that measures the number of axles of the same vehicle, there is a conductive rubber that extends in the width direction of the road and whose resistance changes when subjected to pressure, and a common tread that is affixed to the bottom surface of the conductive rubber with conductive adhesive. an electrode plate, a plurality of electrodes extending along the longitudinal direction of the conductive rubber with small widths attached to the upper surface of the conductive rubber at predetermined distances in the width direction with a conductive adhesive; each of the electrodes and the common electrode; The conductive rubber, the common electrode plate, and each electrode are molded with rubber so as to cover their surroundings. A conductive rubber is used as a sensor for detecting wheel tread pressure, and a common electrode plate is adhered to the bottom surface of the conductive rubber with conductive adhesive, and a common electrode plate is attached to the top surface of the conductive rubber at a predetermined distance in the width direction. A plurality of narrow electrodes extending along the longitudinal direction of the conductive rubber are bonded with conductive adhesive, and these are molded with rubber, thereby creating a contactless structure for the detection part that detects wheel tread pressure. This prevents frictional contact between the conductive rubber and the electrode in the detection section, thereby extending the lifespan and preventing deterioration of durability due to stress concentration deformation. In addition, the change in the resistance value of the conductive rubber 1 that changes due to the wheel pressure of a passing vehicle is applied to a conductive detection member such as a photocoupler connected to an electrode at a position receiving the wheel pressure, so that the conductivity is detected. It is possible to detect the axle of the vehicle based on the condition of the detection member, etc. Deterioration of contact points due to friction etc. and mechanical deformation can be minimized, and durability and reliability can be significantly improved. It is possible to provide a footboard device having excellent features such as being simple.

The present invention is not limited to the embodiments described above and shown in the drawings, and may be modified and practiced as appropriate within the scope of the invention.

[Brief explanation of the drawing]

Figure 1 is a perspective view for explaining the general configuration of a toll booth in an unmanned toll road system, Figure 2 is a sectional view showing the structure of a conventional tread, and Figure 3 is the configuration of the contact body of the tread. 4 is a sectional view showing the state during the detection operation, FIG. 5 is an operation timing chart of each contact body of the footboard, and FIG. 6 is a circuit diagram showing an example of the basic configuration of the present invention. , FIG. 7 is a diagram for explaining the principle of the present invention, and FIG. 8 is a sectional view showing the structure of the pressure sensor. PCR...Conductive rubber, P ₁ , ~P ₄ ... Electrode, P ₀ ...
...Common electrode plate, E...DC power supply, PC,
PC ₁ , ~ _{PC 4} ...Photocoupler.

Claims (1)

[Scope of utility model registration request] A tread plate device that is buried along the width of a vehicle passageway and measures the number of axles of a passing vehicle by the pressure applied by the wheels of the passing vehicle. A conductive rubber, a common electrode plate attached to the lower surface of the conductive rubber with a conductive adhesive, and a small width electrode plate attached to the upper surface of the conductive rubber with a conductive adhesive at a predetermined distance in the width direction. It has a plurality of electrodes extending along the longitudinal direction of the conductive rubber, and a continuity detection member provided in the wiring connecting each of the electrodes and the common electrode plate, and the conductive rubber and the common A treadle device characterized in that an electrode plate and each electrode are molded with rubber so as to cover the periphery thereof.