JPH0315966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle axle load detection device, and more particularly to a load transducer in which a strain gauge is attached to a strain-generating portion of a strain-generating body that deforms elastically when a load is applied. The present invention relates to a vehicle axle load detection device that has a loading plate placed on its upper surface and detects the axle load of a vehicle to be measured placed on the loading plate as an electrical output of the strain gauge.

Overloading a truck or the like not only impairs the drivability of the vehicle itself, but also causes traffic accidents or damage to the road surface. Therefore, in order to determine whether the vehicle is loaded below the legal loading capacity, police, road public corporations, etc. detect the axle load of the vehicle using a vehicle axle load detection device, and calculate the axle weight by the number of axles of the vehicle. The total weight of the vehicle is determined by adding the weights, and enforcement or traffic regulations are implemented based on the results. Conventionally, as a portable axle load detection device for detecting the axle load of a vehicle, those shown in FIGS. 1A to 1C have been widely used.

In the figure, 1 is a load transducer (load cell) that is placed on an installation surface 2 such as a road, with 4 or 6 of them via a pedestal 3, and 4 is a thick-walled load cell that is placed on the top surface of the load transducer. It is a loading plate with great rigidity. In the vehicle axle load detection device 5 having such a configuration, when a vehicle tire is placed on the loading plate 4, a load is applied to the load converter 1, and an electric signal proportional to the load is output. This electrical signal output is subjected to appropriate processing such as amplification, A/D conversion, and arithmetic operations using a vehicle weighing scale (not shown), and then the vehicle weight is displayed and recorded.

However, the conventional vehicle axle load detection device described above has the following drawbacks.

That is, according to the conventional device described above, the wheel load on the tire is supported at six points (sometimes four points) as shown in Figure 1B, so depending on the position of the tire, Most of the load may be applied to one of the six points, so the load transducer must be configured with a large capacity to withstand overload. This has the disadvantage that the height of the load converter increases accordingly and the price also increases.

In addition, since the loading plate 4 of the conventional device described above needs to transmit the load vertically to the load converter 1, it is necessary to reduce the deflection (bending) when the tire load is applied. If this is attempted, it is necessary to considerably increase the thickness t of the loading plate 4, which has the drawback of increasing the height H and weight of the entire device. On the other hand, if the thickness t of the loading plate 4 is reduced in order to reduce the height H and weight of the device itself, a tilted load corresponding to the deflection angle acts on the load converter 1, making it difficult to accurately detect the load. I can't.

Furthermore, when the above-mentioned conventional device actually measures the weight of a vehicle, the measurement is usually performed one axis at a time, as shown in FIG. In this case, a flat plate 6,
7 and inclined plates 8 and 9 are installed on the installation surface 2 such as a road, but not all of the wheels 10a to 10c of the vehicle 10 are placed on the installation surface 2, so for example, as shown in FIG. 4, the axle on which the front wheels 10a are mounted will be elevated, causing the vehicle 10 to tilt. Therefore, it was not possible to accurately measure the axis amount. Considering this point, in order to level the vehicle 10 during measurement, separate flat plates 6, 7,
The same type of inclined plates 8, 9 may also be placed under the middle wheel 10b or the rear wheel 10c, but doing so not only increases the cost but also increases the weight of the inclined plates 8, 9, etc. It is also large and difficult to transport and install, making it extremely inconvenient as a portable device.

The present invention was made to eliminate the drawbacks of the conventional devices as described above, and has a low height, light weight,
It is low in production cost, easy to transport and install, is less susceptible to adverse effects from the installation surface conditions, and is resistant to buckling.
Moreover, it is an object of the present invention to provide a portable vehicle axle load detection device that can accurately measure vehicle axle load.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 is a developed view for explaining the processing step of the strain body, which is the main part of the present invention. In FIG. 3, reference numeral 11 denotes a strain-generating body in an expanded state, which is formed by punching out an elastic thin plate using, for example, a press machine. That is, the whole is formed into an elongated rectangular shape, and the central band in the width direction, that is, the two-dot chain lines PP and Q-Q
A plurality of substantially rectangular holes 12 are bored at predetermined intervals in the longitudinal direction of the band sandwiched by the band, and the rectangular portions sandwiched between the holes 12 are each formed into a strain-generating portion 1.
It is considered to be 3. The portions connected to the left and right ends of the strain-generating portion 13 are a line PP and a line Q- from the corner of each hole 12.
Along the direction Q, slits 14, 14 having a width slightly larger than the wall thickness of the strain body 11 are formed on the upper and lower sides, respectively, and the portion sandwiched between the upper and lower slits is used as a reinforcing rib 15. The zone outside the two-dot chain line PP (upper side in the figure) is the load application section 16, and the zone outside the two-dot chain line Q-Q (lower side in the figure) is the pedestal section 17. However, one of the load applying section 16 and the pedestal section 17, which respectively connect the strain-generating sections 13, is divided by a slit 18 formed therein.

The strain body 11 punched into such a shape is
Next, it is bent. That is, Fig. 4A~
As shown in FIG. C and FIG. , the side plate serving as the strain-generating portion 13 and the bottom plate serving as the pedestal portion 17 are formed to have a U-shaped cross section. Further, the reinforcing rib 15 in which the slits 14 are formed on the upper and lower sides is bent inward at approximately 90 degrees with respect to the plate surface of the strain-generating section 13, and is held between the load applying section 16 and the pedestal section 17. is formed. That is,
The plurality of strain-generating parts 13, 13, . They are connected alternately. Since the connecting portions (the top plate and the bottom plate) are formed extremely thin in the direction of the load, the strain body 11 is extremely flexible. Two strain gauges 19 are attached to the front and back sides of the center of each strain-generating portion 13 by adhesive or other means.

A plurality of strain-generating bodies 11 formed in this manner are installed, for example, on a road, and a relatively thin and flexible loading plate (not shown) is placed thereon as shown in FIG. A vehicle wheel load detection device is configured by placing the vehicle wheel load.

Next, the operation of the above-described embodiment will be described. When the wheels of the vehicle to be measured are placed on the loading plate, the wheel load is applied to the load application section 16 of the strain body 11 via the loading plate. Since the strain-generating portion 13 is sandwiched between the load applying portion 16 and the pedestal portion 17, it receives the compressive load applied to the load applying portion 16.
Compressive strain occurs in the direction of application of the load. Four strain gauges 19 are attached to the front and back surfaces of the central portion of the strain-generating portion 13, and each of the four strain gauges 19 is sensitive to the load application direction and the direction orthogonal thereto.
9 constitutes a Wheatstone bridge, and an electrical signal corresponding to the axle load is output from the output end of the Wheatstone bridge. The electrical signal output from this vehicle axle load detection device is appropriately amplified, subjected to predetermined processing, converted into a load value (axle load value), and then displayed and/or recorded. In the case of this embodiment, the strain generating part 1
The reinforcing ribs 15 provided so as to be connected to the reinforcing ribs 3 are also subjected to compressive strain, but since they are bent perpendicularly to the strain-generating portions 13, they function to prevent buckling of the strain-generating portions 13. .

Next, the present invention will be further explained based on specific numerical values.

When the cross section of the compressive strain part 13 is a groove-shaped (U-shaped) cross section as in the above embodiment, the surface load per unit area of the tire contact surface is P, the cross section of the strain part is S, and the compression generated in the strain part is Assuming that the strain is ε, the tire contact surface is A, and the number of strain-generating portions arranged with respect to the tire contact surface is N, the compressive stress σ generated in the strain-generating portion can be determined from the following equation.

σ=P・A/N・S=ε・E/2.6 (1) Here, E is the longitudinal elastic modulus.

Further, the number N of strain-generating parts required for the entire device is determined by the following equation (2), which is a modification of equation (1).

N=2.6・P・A/ε・E・S (2) Here, in the above formula (2), the surface load P per unit area
is 18.75 Kg/cm ² when the maximum axle load is 30 tons and the size of the contact surfaces of the four tires at the maximum axle load is 200 mm x 200 mm x 4. 4 As shown in Figure (A), the cross section is U-shaped,
Width W ₁ of strain-generating portion 13 = 20 mm, width W ₂ of reinforcing rib 15
= 5 mm and the plate thickness of the strain generating portion 13 is 0.5 mm, the cross-sectional area S of the strain generating portion is 17.28 mm ² . Then, the compressive strain ε=4000×10 ⁶ generated in the strain-generating portion 13,
Longitudinal elastic modulus E=2.1×10 ⁴ Kg/mm ² , loading plate area A=
The size shall be 400mm x 700mm. By substituting these values into the above equation (2) to determine the required number of strain generating parts 13 to be installed below the loading plate, the number is 94.

According to this embodiment configured as described above, a number of advantages shown below can be obtained.

That is, the strain body 11 is formed by punching and bending a very thin elastic plate material, and the height of the strain body 13 in the load application direction can be formed low, and the loading plate is also flexible. Since a relatively thin and durable material is sufficient, the height of the entire vehicle axle load detection device can be configured to be low. Therefore, when the wheels of the vehicle to be measured are placed on the loading plate, the angle of inclination of the vehicle is extremely small, and the influence on the axle load measurement can be kept to a negligible level. For this reason, when measuring accurate vehicle axle loads with conventional devices, the flat plates 6, 7 and inclined plates 8, 9 shown in Figure 2 are installed not only under the wheel to be measured but also under other wheels. However, in the case of this embodiment, there is no need to do so.

Further, in the embodiment described above, since it is possible to provide a much larger number of strain-generating portions 13 serving as support points than in the conventional one, the load is not concentrated locally, and therefore Since it is not necessary to use a high-capacity strain-generating portion, it is possible to have a small-capacity, high-precision strain-generating portion.

In addition, the strain-generating body 11 of this embodiment can be manufactured by simply punching out a thin elastic plate and bending it, without cutting or the like as required in the past, so raw material costs and processing costs can be significantly reduced. can be reduced.

Further, since the strain body 11 is made of a thin plate material as described above, it is extremely light, and the device can be easily transported and installed.

Further, the strain-generating body 11 of this embodiment is flexible and has many support points as described above, and the surface pressure is extremely small, so that it can be used even on a softened road surface or an uneven road surface.

Furthermore, reinforcing ribs 15 connected to the strain-generating portion 13
Since the cross section (horizontal cross section) of the strain generating part is made U-shaped, the structure is extremely resistant to buckling even though the cross sectional area is small. This will occur on the 13th.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications.

For example, a plurality of strain-generating bodies 11 as shown in FIG. 4 are arranged side by side, and a loading plate is placed on the upper surface of the strain body 11, and a pedestal plate is placed on the lower surface of the flexure-generating bodies 11. A molding material such as liquid rubber can be filled in between. By doing so, it is possible to prevent deterioration of the strain gauge due to moisture absorption, and it is also useful to prevent buckling of the strain generating portion.

Further, in the above embodiment, the slits 18 are provided alternately in the intermediate portions of the top plate and the bottom plate that connect each strain-generating portion to each other, but the slits 18 are not limited to this. The strain-generating parts may be connected to each other by either the top plate or the bottom plate.

As detailed above, according to the present invention, the height is low, the weight is light, the manufacturing cost is low, it is easy to transport and install, is resistant to buckling, and can be installed on soft or uneven road surfaces. A portable vehicle axle load detection device capable of accurately detecting vehicle axle load can be provided.

[Brief explanation of the drawing]

1A, B, and C are a front view, a plan view, and a side view showing the configuration of a conventional device; FIG. 2 is a side view showing a state in which the conventional device is used to measure the axle load of a vehicle; The figure is a developed view of the strain-generating part, which is the main part of the present invention, and Figures 4A, B, and C are plan views and front views showing the structure of the strain-generating body of the present invention, and the X-X line in Figure B. The sectional view and FIG. 5 are perspective views of the strain body 11 of the same embodiment. 11... Strain body, 12... Approximately rectangular hole, 13...
... strain generating part, 14, 18 ... slit, 15 ... reinforcing rib, 16 ... load application part, 17 ... pedestal part,
19...Strain gauge.

Claims (1)

[Claims] 1. A loading plate is placed on the top surface of a load transducer in which a strain gauge is attached to the strain-generating part of a strain-generating body that deforms elastically when a load is applied, and the axle load of the vehicle to be measured is measured on the loading plate. In the detection device, a top plate, a side plate, and a bottom plate form a strain-generating body having a U-shaped cross section, and a plurality of approximately rectangular holes are bored in the side plate at predetermined intervals in the longitudinal direction. The portions sandwiched between the shaped holes are respectively made into strain-generating portions, and the portions connected to the left and right ends of the strain-generating portions are bent inward and sandwiched between the top plate and the bottom plate to form reinforcing ribs. The intermediate portion of one of the top plate and the bottom plate that is provided and connects adjacent strain-generating portions to each other is separated, and the top plate portion formed as described above is used as a load application portion; A load transducer in which the bottom plate is used as a pedestal and strain gauges for detecting compressive strain are attached to both sides of each of the strain-generating parts, and a plurality of the load transducers are arranged on an installation surface to apply loads. 1. A portable vehicle axle load detection device comprising: a loading plate that is placed on the load plate and on which wheels of a vehicle to be measured are placed;