JPH0423731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle type discrimination device used in an automatic toll collection system on a toll road or a parking lot, and particularly relates to an improvement of a treadle.

[Conventional technology]

Generally, in a toll collection system for a toll road or a parking lot, a vehicle type discrimination device is installed to discriminate the type of vehicle passing by.

FIG. 6 is a schematic diagram showing an example of a toll collection system on a toll road. In Figure 6, 1
is a passing vehicle, and vehicle approach road 2 of the tollgate gate
The vehicle moves in the direction indicated by arrow A in the figure. 3 is a booth for issuing passes or collecting tolls; inside this booth 3,
The ticket processing unit 4 that performs processing such as issuance of tickets (toll gate entrance) or reading of tickets (toll gate exit), control of the ticket processing unit 4, vehicle type information, entrance gate number, date, time, etc. A controller 5 is installed which performs toll calculations based on pass ticket data, etc., as well as aggregation and recording of various management data such as toll collection data and pass ticket processing data.
Further, 6 is a vehicle type discrimination device that sends vehicle type information to the controller 5. This vehicle type discrimination device 6 is composed of a plurality of photoelectric switches, and vehicle separators 7a and 7 are installed facing each other across the vehicle approach road 2.
b, and a footboard 8 buried in the road surface below the optical axis of the vehicle separators 7a, 7b. The vehicle separators 7a and 7b detect when a passing vehicle 1 blocks a light screen placed perpendicular to the road surface, and separate and detect the passing vehicle 1 one by one. The number of axles, number of wheels (tire width), and tread (outer dimension of tires) while passing vehicle 1 is passing.
This system automatically determines the vehicle type by measuring factors such as vehicle type discrimination factors.

FIG. 7 is a longitudinal cross-sectional view showing the structure of the step board 8. As shown in FIG. The tread 8 is entirely formed of a rubber plate 9, and has four rectangular cavities 10 in the center.
a, 10b, 10c, and 10d are provided.
The flat contact body S1 and the resistance contact body R1 are inserted into the cavity 10a, and the cavities 10b and 10
A flat contact body S2, S3 is inserted into the cavity 10d, and a flat contact body S4 and a resistance contact body R4 are inserted into the cavity 10d. In addition, each of the above contact bodies S1
~S4 and R1, R4 are the substrates 11 made of steel plates
Supported by

FIG. 8 is a longitudinal sectional view showing the structure of the flat contact bodies S1 to S4 (hereinafter collectively referred to as S). In FIG. 8, 12a and 12b are an elastic upper electrode and a lower electrode, and these electrodes 12a,
12b is covered with insulating sheets 13a and 13b made of polyester, for example, except for opposing portions. Therefore, when a passing vehicle 1 passes above the flat contact body S, the upper electrode 12a is bent by the pressure of the tires of the vehicle 1, and comes into contact with the lower electrode 12b, causing a short circuit between the two electrodes. becomes. Thus, by detecting a short circuit between the two electrodes, the tire tread pressure is detected. Note that 14 is the insulating sheet 13a, 13b.
It is a core that holds the electrodes 12a and 12b covered in the front and back, and up and down, and has a rigid structure.

FIG. 9 is a longitudinal sectional view showing the structure of the resistance contact bodies R1 and R4 (hereinafter collectively referred to as R). In FIG. 9, 15a and 15b are an elastic upper electrode and a lower electrode, and the upper electrode 15a is covered with an insulating sheet 16 made of polyester, for example, except for a portion facing the lower electrode 15b. Therefore, similarly to the flat contact body S,
When a passing vehicle 1 passes above the resistance contact body R,
The upper electrode 12a and the lower electrode 12b are short-circuited.

On the other hand, the lower electrode 15b has a structure in which it is divided into a plurality of pieces (n pieces) in the longitudinal direction as shown in FIG.
1 to rn. Therefore, in the resistance contact R, the resistance is short-circuited by the width of the foot stepped on by the tire of the passing vehicle 1. In this way, the tire width (number of wheels) is detected by detecting the change from the total resistance value, and the tire pressure position is detected from the resistance value between the upper electrode 15a and one of the resistors. ing.

In addition, in FIG. 9, 17 is the lower electrode 15.
It is a support body that supports b, and has a rigid structure. The support body 17 has two grooves 18a, 18.
The lead wires of the divided electrodes p1 to pn are drawn out from the groove 18a on the right side in the figure, and each contact body S is drawn out from the groove 18b on the left side in the figure.
Lead wires 1 to S4 and R1 and R4 are drawn out. Further, 19 is each of the electrodes 15
This is the core that houses the elements a and 15b, and also has a rigid structure.

FIG. 11 is a diagram showing the arrangement of the above-mentioned contact bodies S1 to S4 and R1, R4 in the longitudinal direction of the treadle. As is clear from FIG. 11, the resistance contact bodies R1 and R4 are arranged on the left and right so that they do not overlap in the width direction, and the passing vehicle 1
1. It is designed not to step on R4 on both the left and right sides at the same time. In addition, flat contact bodies S1 and S4 are used to binarize the presence or absence of a change in the resistance value, as well as the analog quantity that is the change from the total resistance value mentioned above, to compensate for the short length of the resistance contact bodies R1 and R4. The logical sum of the flat contact signals is calculated. Furthermore, the reason why four contact bodies are arranged in the direction of the vehicle signal as shown in FIG. 11 is to determine whether the vehicle is moving forward or backward by detecting the order in which the pedals are pressed.

In this way, the conventional vehicle type identification device 6 uses the vehicle separators 7a and 7b to separate and detect passing vehicles 1 one by one, and also measures the number of wheel axles, number of wheels, tread, etc. using the tread plate 8. It is designed to identify the vehicle type.

[Problem that the invention seeks to solve]

However, vehicle type classification in the toll system on current toll roads is determined not only by the number of axles, the number of wheels, and the tread, but also by the loaded weight of the vehicle, the number of passengers, etc. Therefore, the conventional vehicle type identification device 6
However, since it is not possible to detect the loaded weight of the vehicle, the number of passengers, etc., the accuracy of vehicle type identification has decreased, and improvements have been desired.

Therefore, the present invention makes it possible to add an axle load detection function in addition to the determining factors such as the number of axles, the number of wheels, and the tread at a low cost and in a small space with a small number of parts. An object of the present invention is to provide a vehicle type discrimination device that can improve the accuracy of vehicle type discrimination in a toll system.

[Means for solving problems]

The present invention provides a vehicle separator configured with a plurality of photoelectric switches, and a thin flat contact body and a resistance contact body that are buried in the road surface under the optical axis of the vehicle separator and inserted above a cavity. In addition, the step plate is made of an elastic body and has a load sensor inserted below the hollow portion, and the load sensor is provided with a rigid structure support body having a convex portion and a support body disposed on the convex portion of the support body. a piezoelectric element, a pressure receiving plate having a rigid structure having a recess that fits into a convex part of the support, and a state in which the concave part of the pressure receiving plate is fitted into the convex part of the support on which the piezoelectric element is disposed; It is equipped with a gap formed between the pressure receiving plate and the support body.

[Effect]

With the present invention having such a configuration, the displacement of the piezoelectric element in the load sensor due to the load is negligibly small compared to the displacement of the flat contact body and the resistance contact body, so the load sensor is almost a rigid body when viewed from each contact body. It can be considered as As a result, when a vehicle that is separated and detected by the vehicle separator passes over the tread, the elastic tread is bent due to the load of the vehicle, and the flat contact body and the resistive contact body are displaced. Based on this, vehicle type identification factors such as the number of axles, number of wheels, and tread are measured.

Further, the entire load of the vehicle is applied to the pressure receiving plate of the load sensor. As a result, the piezoelectric element supported by the support is compressed, and the axle load of the passing vehicle is detected based on the output voltage proportional to this compressive strain.

〔Example〕

FIG. 1 shows a treadle 2 in a first embodiment of the present invention.
FIG. Note that the same parts as in FIG. 7 are given the same reference numerals and detailed explanations will be omitted. In this embodiment, the shape of the treadle 20 is the same as that of the conventional treadle 8, so that they are compatible. On the other hand, above the cavities 10a-10d, contact bodies S1-S4 and R1, R4, which are functionally the same as the conventional one but have a reduced thickness, are inserted. In addition, the cavity portions 10a to 10
An axle load sensor L made of a piezoelectric element is inserted below d.

FIG. 2 is a longitudinal sectional view of the axle load sensor L.
In FIG. 2, 21 is a piezoelectric element made of, for example, a plastic piezo sheet, and electrodes 22a and 22b are attached to both sides of this piezoelectric element 21.
Further, the piezoelectric element 21 to which the electrodes 22a and 22b are attached is entirely covered with an insulator 23 made of a heat-shrinkable tube or the like. and the piezoelectric element 2
1 generates an output voltage proportional to the amount of strain when force is applied in the thickness direction and strain occurs, and this output voltage can be taken out from the electrodes 22a and 22b.

Further, in FIG. 2, 24 is a pressure receiving plate having a concave portion, and 25 is a support body having a convex portion, each of which has a rigid structure. Then, the support body 25
Piezoelectric element 21 covered with the insulator 23 on top of
The pressure receiving plate 24 is fitted onto the pressure receiving plate 24, and the outer periphery of the pressure receiving plate 24 is sealed with an insulator 26. Therefore, the insulation of the piezoelectric element 21 has a double structure. In addition, the pressure receiving plate 24 and the support body 2
A slight gap Δg is provided between the pressure receiving plate 24 and the supporting body 25, so that even if a load is applied to the pressure receiving plate 24 and displacement occurs, the pressure receiving plate 24 and the support body 25 do not come into close contact with each other.

The reason why the pressure-receiving plate 24 and the support body 25 are designed to fit together in this way is that even if a load is applied to the pressure-receiving plate 24 from an oblique direction, it acts as a non-slipper, and prevents horizontal shearing force from being applied to the piezoelectric element 21. This is to prevent it from being transmitted. Note that almost no frictional force is generated in the vertical direction.

Next, the operation of this embodiment will be explained. In the axle load sensor L, the displacement due to the load of the piezoelectric element 21 is caused by the upper electrodes 12a, 1 in each contact body S, R.
Since the displacement is negligibly small compared to the displacement due to the load of 5a, the axle load sensor L can be regarded as a substantially rigid body when viewed from each contact body S, R. Therefore, when the passing vehicle 1 presses the tread plate 20, the rubber plate 9 forming the tread plate 20 is bent, and each contact body S, R
When the upper electrodes 12a, 15a are pressurized, the upper electrodes 12a, 15a bend in a shape that follows the pressure of the tire, and the lower electrodes 12b, 15a respectively bend.
shorted to b. As a result, the pressure on the tires of the passing vehicle 1, the change in resistance proportional to the length of the tire tread, and the tread position of the resistive contact R are detected by the electrodes 12a, 12b and 15a, 15b. Then, based on this detection output and the order in which the contact bodies S and R are stepped on, a known control device measures vehicle discrimination factors of the passing vehicle 1, such as forward/reverse motion, number of wheels, tread, etc. for each axis.

On the other hand, the entire load of the passing vehicle 1 that has caused the upper electrodes 12a, 15a to bend is applied to the pressure receiving plate 24 of the axle load sensor L. Then, the piezoelectric element 21 supported by the support plate 25 is compressed, and the piezoelectric element 2
1, an output voltage proportional to the compressive strain is generated. That is, this output voltage becomes the axle load of the passing vehicle 1, and is detected via the electrodes 22a and 22b.
The axle loads of passing vehicles 1 measured for each axis are stored in a storage device. And vehicle separators 7a, 7
At the falling edge of the passing signal detected at b, the total axle load is added, and the total weight of the passing vehicle 1 is measured.

Thus, according to the present embodiment, in addition to the conventional vehicle discrimination factors such as the number of axles, the number of wheels, and the tread, it is now possible to detect the vehicle weight, thereby greatly improving the accuracy of vehicle type discrimination. Moreover, the flat contact body and resistance contact body are made thin and mounted above the hollow part of the treadle,
Since a load sensor with a rigid structure is installed below the cavity when viewed from each contact body, a conventional treadle that can detect the number of axles, number of wheels, tread, etc. can be used, and a treadle exclusively for axle load detection is available separately. There's no need to. Therefore,
It has the advantage of requiring a small number of parts and can be constructed relatively inexpensively and in a small space. In addition, the piezoelectric element 21
Since the piezoelectric element 21 is held by fitting the concave pressure receiving plate 24 and the convex support plate 25, it is possible to prevent horizontal loads such as sideways sliding from being applied to the piezoelectric element 21. Therefore, the piezoelectric element 21 can only detect vertical loads. As a result, the piezoelectric element 21, which is soft and has poor shearing force, such as a plastic piezo,
can be applied as an axle load meter for vehicles that are used repeatedly and under heavy loads.

FIG. 3 shows a treadle 3 in a second embodiment of the present invention.
FIG. This embodiment differs from the first embodiment in that the four cavities 10a
At the bottom of the contact bodies inserted above ~10d, there are independently axle load sensors L each consisting of a piezoelectric element.
1 to L4 are provided.

FIG. 4 is a longitudinal sectional view showing an example of how the axle load sensor L1 or L4 is inserted into the resistance contact R. The electrodes 15a, 15b, the insulating sheet 16, and the resistors r1 to rn, which constitute the resistance contact body R, have the same shape and function as the conventional type shown in FIGS. 9 and 10. However, the support 17' of the lower electrode 15b is designed to be thinner than the conventional type. On the other hand, axle load sensors L1 and L4
Also, the piezoelectric element 21, electrodes 22a, 22b,
The insulator 23 and the support 25 have the same functions as in the first embodiment. However, the pressure receiving plate 31 is H-shaped and also serves as the core of the resistance contact body R. Further, the fitted state between the pressure receiving plate 31 and the support body 25 is similar to the fitted state in the first embodiment. Thus, support 2
A piezoelectric element 21 is placed on top of the piezoelectric element 21, a pressure receiving plate 31 is fitted on top of the piezoelectric element 21, a resistance contact body R is further installed in the recess of the pressure receiving plate 31, and the entire structure is sealed with an insulator 32. ing.

FIG. 5 is a longitudinal sectional view showing an example of how the axle load sensor L2 or L3 is inserted into the flat contact body S. The electrodes 12a, 12b and insulating sheets 13a, 13b that make up the flat contact body S have the same shape and function as the conventional type shown in FIG. On the other hand, axle load sensor L2, L
3, the piezoelectric element 21, electrodes 22a, 22
b, the insulator 23, and the support 25 have the same functions as in the first embodiment. However, the pressure receiving plate 33 is H-shaped and also serves as the core of the flat contact body S. In addition, the pressure receiving plate 3
3 and the support body 25 is the same as that in the first embodiment. Thus, the piezoelectric element 21 is placed on the support plate 25, the pressure receiving plate 33 is fitted on top of the piezoelectric element 21, the flat contact body S is installed in the recess of the pressure receiving plate 33, and the whole is covered with an insulator 34. It has a sealed structure.

Note that the electrodes 22a and 22b attached to both sides of the piezoelectric element 21 of each of the axle load sensors L1 to L4 are as follows:
They are each connected in parallel externally.

In this embodiment configured in this way, by adding the output voltages generated by the piezoelectric elements 21 in each of the axle load sensors L1 to L4, an output voltage proportional to the total axle load can be obtained.
In addition to having the same effect as the first embodiment, the core, which only served as a support for the contact bodies S and R in the first embodiment, is now a pressure receiving plate that transmits the load to the piezoelectric element 21. It has become possible to combine the functions of

〔Effect of the invention〕

As described in detail above, according to the present invention, in addition to determining factors such as the number of axles, number of wheels, and tread, an axle load detection function can be added at low cost and in a small space with a small number of parts, and equipment costs can be reduced. It is possible to provide a vehicle type discrimination device that can improve the accuracy of vehicle type discrimination in toll systems on toll roads, etc. without increasing the number of vehicle types.

[Brief explanation of drawings]

1 and 2 are diagrams showing a first embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view showing the configuration of a footboard;
FIG. 2 is a longitudinal sectional view showing the configuration of the axle load sensor. 3 to 5 are diagrams showing a second embodiment of the present invention, FIG. 3 is a diagram showing the configuration of a footboard, and FIG. 4 is a diagram showing an example of combining a resistance contact body with an axle load sensor. FIG. 5 is a diagram showing an example of combining a flat contact body and an axle load sensor. Figures 6 to 11 are diagrams for explaining conventional examples, with Figure 6 being a schematic diagram of the toll collection system, Figure 7 being a vertical cross-sectional view showing the configuration of the treadle, and Figure 8 being a flat contact. 9 is a longitudinal sectional view showing the structure of the resistive contact body, FIG. 10 is a longitudinal sectional view showing the configuration of the lower electrode in the resistive contact body, and FIG. 11 is a diagram showing the arrangement of each contact body. It is a figure for explaining. 1...passing vehicle, 6...vehicle type identification device, 7a,
7b...Vehicle separator, 8,20,30...Treadboard,
9...Rubber plate, 10a, 10b, 10c, 10d
. . . Cavity, 11 . 31, 33...pressure receiving plate,
25... Support plate, 26, 32, 34... Insulator.

Claims (1)

[Claims] 1. A vehicle separator composed of a plurality of photoelectric switches, and a thin flat contact body and a resistive contact body buried in the road surface under the optical axis of the vehicle separator and above a cavity. The step plate is made of an elastic body and has a load sensor inserted below the hollow portion, and the load sensor has a rigid structure support having a convex portion, and the load sensor is mounted on the convex portion of the support. a piezoelectric element disposed on the support body; a pressure receiving plate having a rigid structure having a concave portion that fits into the convex portion of the support body; A vehicle type discriminating device comprising: a gap formed between the pressure receiving plate and the support body in a fitted state.