JPH04213027A - Vehicle-weight measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve the light weight by using a piezoelectric material for a weight detecting part for a vehicle and to make it possible to measure the weight of the vehicle during the running. CONSTITUTION:A plurality of detecting plates comprising a piezoelectric material are arranged in the running direction of a vehicle in the electrically independent pattern in a voltage detecting part 1. A signal processing part 3 receives the signals from the detecting plates, computes the speed of the vehicle and measures the weight of the vehicle based on the relationship between the speed and the voltage signals from the detecting plates. A display part 4 displays the measured weight. This apparatus have the above described parts.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the weight of a vehicle.

0002

2. Description of the Related Art Conventionally, as this type of device, there are only trucks as shown in FIG. In the figures, (a) is a plan view, and (b) is a side view. This principle is based on a platform 16 on which a strain gauge is attached to an elastic block and a load cell 15 is placed, which generates an electric signal proportional to the deformation of the elastic body.
The weight of the vehicle is measured by placing a vehicle on it and detecting an electrical signal proportional to the load.

0003

However, with the above configuration, the device is large and heavy, and therefore it is difficult to move the device. For example, if you look at all the ground-type trucks that weigh 40 tons, the total length is about 17.5 m, and the width is about 4 m.
The scale weighs approximately 3.5 tons and cannot be easily moved. In addition, it has been completely impossible to measure the weight of a moving vehicle.

The present invention was made to solve the above-mentioned problems, and it not only reduces the weight of the device so that it can be moved more easily, but also measures the weight of a moving vehicle. The purpose is to provide a device with improved measurement accuracy.

[0005]

[Means for Solving the Problems] A first invention includes a voltage detection section in which a plurality of detection plates made of piezoelectric material are electrically independent and arranged in the running direction of a vehicle, and a signal is input from the detection plates. The vehicle is equipped with a signal processing section that calculates the speed of the vehicle and measures the weight of the vehicle based on the relationship between the speed and the voltage signal from the detection plate, and a display section that displays the measured weight.

[0006] In a second invention, in the first invention, with respect to the vertical load of the vehicle applied to each of the detection plates, a load component acting in a direction opposite to the running direction generated by the rolling force of the wheels is applied to the vehicle while the vehicle is running. This is a correction related to speed.

[0007]

[Operation] When the vehicle passes the voltage detection section at a certain speed, the generated voltage from each detection object is input to the signal processing section. Furthermore, the signal processing section calculates the speed of the vehicle from the transit time between two detected objects separated by a certain distance. On the other hand, the relationship between the speed, the generated voltage, and the vertical load is stored in advance in the signal processing section, and the weight of the vehicle is measured from these speeds and voltages and displayed on the display section.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a voltage detection section comprising a plurality of detection objects made of piezoelectric material arranged in two rows, 3 a signal processing section connected to each detection object, 4 a weight display section, and 5 a weight recording section. It is. 2 is a side sectional view of the voltage detection section 1, and FIG. 3 is a plan view of the voltage detection section 1. 2 and 3, 6 is a piezoelectric ceramic such as lead titanium zirconate, 7 is an electrode, and 8 is a piezoelectric ceramic such as lead titanium zirconate.
9 is a urethane resin that protects the periphery of the piezoelectric ceramic 6, and 9 is a cable drawn out from the electrode of the piezoelectric ceramic. Reference numerals 101 to 200 and 201 to 300 are detection bodies made of piezoelectric ceramics 6 and electrodes 7, and have a width of 50 mm, for example.
Each detection body 101-200, 201-300 is electrically independent from the other detection bodies.

Next, the operation will be explained. First, the signal processing section 3 stores in advance a weight calibration curve as shown in FIG. 4, which represents the relationship between the speed of the vehicle, the voltage generated by the detection object, and the vertical load. When the vehicle 11 is traveling in the direction of arrow A and the entire vehicle 11 is placed on the voltage detection section 1, the signal processing section 3 detects each detection object 101-200, 201-3.
00, and calculates the total generated voltage caused by the vehicle 11. Further, the signal processing unit 3 calculates the speed of the vehicle 11 based on the time it takes the vehicle 11 to pass two detection objects, for example, 101 to 200, and the distance thereof. Then, the weight of the vehicle is calculated from this speed and the total generated voltage using the aforementioned weight calibration curve. Now, if the speed is x and the total generated voltage is y, then in the example of FIG. 4, the weight of the vehicle 11 is calculated to be 5 tons,
This value is displayed on the weight display section 4 and recorded on the recording section 5. Note that the signal processing unit 3 is programmed to calculate an appropriate value even if the intersection of voltage and speed is located in the middle of the graph of FIG. 4.

In the above embodiment, the detection plates 101 to 200, 20
1 to 300, in addition to the vertical load, there is a load due to rolling friction force in the opposite direction to the running direction due to the rolling force of the wheels, but this is related to the running speed, so it is corrected in relation to the speed, and when it is stationary The aim is to obtain the same effect as when measured using Note that this relationship is not uniform, so experiments and the like are performed in advance and stored in the signal processing section.

Although a piezoelectric ceramic is used for the detection plate in the above embodiment, an organic piezoelectric material such as polyvinylidene fluoride, or a composite piezoelectric material made of a polymeric material such as lead titanium zirconate may also be used. Tables 1 and 2 show the piezoelectric ceramics (manufactured by Oki Ceramic Industry) used in the above examples.
Let us show the piezoelectric constant of

0012

[Table 1]

[0013]

[Table 2]

[0014] Furthermore, the weight of a voltage detecting section with a length of 5 m and a width of 2 m, which can measure a vehicle weighing less than 10 tons, is approximately 20 to 30 kg when piezoelectric ceramics are used; Approximately 2-5 when using
kg, approximately 10-20 kg when using composite piezoelectric material
becomes.

Finally, let us consider the strength of the detection plate. Regarding the strength when a vehicle load is applied to the voltage detection part, if the detection plate is an organic piezoelectric material or a composite piezoelectric material made of a titanium lead zirconate piezoelectric ceramic and a polymer material, the detection plate is made of a polymer material. , it will not crack and be destroyed.

The compressive strength of the titanium lead zirconate based piezoelectric ceramic is 20 kg/mm2. When measuring a vehicle with a total load of 10 tons using this piezoelectric ceramic as a detection object, this load is distributed among the four tires, so
One tire carries a load of 2.5 tons. Now, 1
If one tire with a width of 150 mm and a length of 100 mm is in contact with the detection object, the area thereof will be 15,000 mm2, and the load on the tire portion will be 0.17 kg/mm2. Therefore, the strength of the piezoelectric ceramics used is 20 kg/m.
m2 has sufficient strength for this and there is no problem.

[0017]

As described above in detail, the present invention uses a voltage detection section configured with a plurality of electrically independent detection bodies made of piezoelectric material to detect the weight of a vehicle, and a signal processing section from this detection section. As a result, by providing a display section, the weight of the vehicle weight measuring device has been significantly reduced, making it easier to transport and moving, and also making it possible to measure the weight of a vehicle while it is running.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a side sectional view of a voltage detection section.

FIG. 3 is a plan view of a voltage detection section.

FIG. 4 is a diagram showing the relationship between vehicle speed and generated voltage.

FIG. 5 is a structural diagram of a conventional truck.

[Explanation of symbols]

1 Voltage detection section 3 Signal processing section 4 Display section 5 Recording Department 6 Piezoelectric ceramics 7 Electrode 8 Urethane resin 9 Cable 101-300 Detection object

Claims (2)

[Claims] 1. A voltage detection unit including a plurality of electrically independent detection plates made of piezoelectric material and arranged in the running direction of the vehicle;
a signal processing unit that inputs a signal from the detection plate to calculate the speed of the vehicle and measures the weight of the vehicle based on the relationship between the speed and the voltage signal from the detection plate; and a display unit that displays the measured weight. A vehicle weight measuring device comprising: 2. With respect to the vertical load of the vehicle applied to each of the detection plates, a load component acting in a direction opposite to the running direction generated by the rolling force of the wheels is corrected in relation to the running speed of the vehicle. The vehicle weight measuring device according to claim 1, characterized in that: