JPH02257022A - Instrument for measuring axial load of vehicle - Google Patents

Abstract

PURPOSE:To measure the axial load of a vehicle with high accuracy by providing a platform of the height equal to the height of a road surface, load sensors provided under the platform in a passing direction, a load signal adder, a signal generator corresponding to the loading time, an integrator and a divider. CONSTITUTION:The signals of the load cells 4, 4' are added, are amplified and are added to the integrator 9. A differential constant is set in a differentiat ing circuit 8a of an integrating period forming circuit 8 in such a manner that a large voltage is generated between the time when a wheel 1 arrives at the position l1 of the platform 3 from the road surface 2 and the time when the wheel descends onto the road surface 2 from a position l2. Comparator circuits 8b, 8c compare the output of the differentiating circuit 8a respectively with reference values V1, V2, drive an FF 8d and output the pulses corresponding to the integrating period T. The voltage proportional to the period T is formed by a generator 10 and the divider 11 divides the outputs of the integrator 9 by the output of a voltage generator 10. The axial load of the vehicle is thereby measured with the high accuracy without being affected by a road condition and driving operations.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle axle load measuring device for accurately measuring the axle weight of various vehicles, particularly freight vehicles.

[Prior Art] In recent years, as the proportion of freight vehicles used to transport goods has increased, there has been a tendency for vehicles to become larger. Among these types of vehicles, there are many overloaded vehicles that exceed the legal axle load, which accelerates the progression of road damage and shortens the service life of the vehicle.It also places an excessive load on the engine and vehicle body. This increases noise, vibration, exhaust gas, etc., which has a negative impact on the surrounding environment, and increases the weight of the vehicle, which lengthens braking distance and reduces maneuverability, which can lead to accidents. It was happening.

Therefore, in order to control such overloaded vehicles, a vehicle axle load measuring device is known as a device that measures the axle weight of a vehicle traveling on a road.

For example, conventional devices calculate the axle load of a vehicle by capturing the maximum value of the load signal applied to the platform when the wheel passes over the platform, and devices that calculate the axle load of the vehicle by capturing the maximum value of the load signal applied to the platform when the wheel passes over the platform. There is a method that calculates the average value while exceeding the limit.

[Problems to be Solved by the Invention] By the way, in an ideal state where a vehicle traveling on a road maintains uniform road surface flatness, the detected axle load waveform as shown in Fig. 1(b) is stable without variation while the wheels are passing over the platform. However, since the actual road surface has undulations and is not constant, the vehicle bounces up and down depending on the condition of the road surface, and the detected axle load waveform has a level difference R as shown in Figure 1 (c). occurs.

Further, this level difference R is caused not only by the condition of the road surface but also by individual differences in the driving operation of the vehicle, such as differences in the degree of operation of the accelerator, brake, etc. Therefore, in order to accurately measure the axle load of the vehicle, it is necessary to average the signals detected during the time t when the wheels of the vehicle are completely resting on the platform.

However, when the vehicle weight is measured using the above-mentioned conventional vehicle axle load measuring devices under conditions where driving operations are different and the road surface is not constant, these devices sample signals exceeding a certain level. If the peak value of this sampled signal is taken as the weight of the vehicle, it will always be larger than the true weight (R in Figure 1 (c)
If you decide to measure the vehicle weight using the average value of signals that exceed a certain level, you will always measure a value that is smaller than the true weight (A1 and A2 in Figure 1 (b)). Therefore, there was a problem in that accurate measurements could not be performed.

Therefore, the present invention has been made in view of the above-mentioned problems, and its purpose is to provide a vehicle axle load measuring device that can measure the axle load with high precision without being affected by road conditions or driving operation conditions. Our goal is to provide the following.

[Means for Solving the Problems] In order to achieve the above object, the axle weight measuring device according to the present invention includes a platform whose top surface is installed at the same height as the road surface, and a platform that measures loads applied to the front and rear in the vehicle passing direction. A plurality of load detectors arranged under the above-mentioned table, an adder circuit for adding the load detection signals generated from the load detectors, and the added value signal in order to generate signals of respective sizes. a device that generates a signal corresponding to the time when the load is applied on the table; an integrator that integrates the added value over the time; The present invention is characterized by comprising a divider that divides by the signal and calculates the load applied to the table.

[Operation] When the vehicle passes over the platform, the load signals generated in the plurality of load detectors are added and the axle load is output. and,
When a signal corresponding to the time from the point where the added signal finishes rising to the point where it begins to fall is generated, the added signal is integrated during this signal, and by dividing this integrated value by the integrated time, the The axial load of is measured.

[Example] Fig. 2 shows an example of the vehicle axle load measuring device according to the present invention.

In FIG. 2, it is considered that the load W on the wheel 1 is evenly distributed over its ground contact width.

The platform 3 is provided so as to be flush with the road surface 2, and this platform 3 is equipped with a plurality of load sensors, such as strain gauge type load cells (hereinafter abbreviated as load cells) 4, 4, arranged at the front and rear in the vehicle passing direction. 'Supported by. The platform 3 does not move in the vehicle passing direction, and is provided with a load transmission mechanism 5 that transmits the load applied to the platform 3 to the load cell 4.4'.

Signals from the load cells 4 and 4° are combined by an adder 6, and amplified by an amplifier 7 to an electric signal proportional to the load to an appropriate magnitude.

The integrator 9 integrates the output signal of the amplifier 7 for a period T.

Voltage generator 10 generates a voltage proportional to period T.

Divider 11 divides the output signal of integrator 9 by the output signal of voltage generator 10 .

The display 12 displays the output signal of the divider 11 in units of load.

By the way, the integral period generation circuit 8 is configured so that the wheel 1 is located from the position 9.1 on the platform 3! A differentiation circuit 8a that differentiates the output signal of the amplifier 7, and a first circuit that generates the period T until the signal passes through the amplifier 7 and compares the output signal of the differentiation circuit 8a with a predetermined reference signal ■1. a second comparison circuit 8c that compares the output signal of the differentiating circuit 8a with a predetermined reference signal v2; A flip-flop circuit 8d generates an integration period T based on the outputs of the second comparison circuits 8b and 8c.

Furthermore, to explain in detail each part of this integral period generating circuit 8, the differentiating circuit 8a generates a large voltage in the positive direction from the time when the wheel 1 is transferred to the platform 3 until it reaches the position ℃1, and when the wheel 1 is at the position The differential constant is set so that a large voltage is generated in the negative direction during the transfer from 12.2 to the road surface 2 from the platform 3.

While the output signal from the differentiating circuit 8a exceeds the reference value (voltage level +v, , r), the output of the first comparison circuit 8b becomes high level and is input to the set input terminal of the flip-flop circuit 8d. .

The set input terminal of the flip-flop circuit 8d is an input terminal that sets the output of the flip-flop circuit 8d to a high level when the signal level drops from a high level to a low level.

While the output signal from the differentiating circuit 8a is lower than the reference value 2 (voltage level -Vref), the output of the second comparison circuit 8C becomes high level and is input to the reset input terminal of the flip-flop circuit 8d. flip-flop circuit 8d
The reset input terminal is a terminal that resets the output of the flip-flop circuit 8d to low level when the signal level rises from low level to high level. The flip-flop circuit 8d thus outputs a pulse corresponding to the integration period T.

Next, the operation of the vehicle axle load measuring device configured as described above will be explained.

Now, when the wheel 1 carrying the load W passes over the platform 3 in the passing direction, the total load applied to the load cells 4 and 4° is f (as shown in the curve of Xi) shown in Fig. 3(b). However, the load applied to each load cell 4, 4° is as follows.

As shown in FIG. 3(a), wheels 1 having a predetermined ground contact width
Assuming that the load W is applied evenly to the ground contact width, the load applied to the load cell 4 becomes g (Xi) in Fig. 3(b), and the load applied to the load cell 4° is as shown in Fig. 3(b).
h (Xl), and f in Fig. 3(b)
(XI is the output signal g of the load cell 4.4° (XI
This is the signal obtained by adding h f The target axle weight can be measured only during the period T during which the load W of the wheel 1 is completely applied to the platform 3.

Thereafter, the output of the adder 6 is suitably amplified by an amplifier 7 to an electric signal proportional to the axle weight. It is integrated. The output of this integrator 9 is divided by a divider 11 by the output signal of a voltage generator 10 which generates a voltage proportional to the period T, thereby determining the axle weight.

Here, to explain in detail the operation of the integral period generating circuit 8, the differential constant of the differentiating circuit 8a is determined by the differential constant of the differentiating circuit 8a, as shown in FIG. Standing from the time you transfer to position 3 until you reach position ρ1
When there is a two-way signal, a large voltage is generated in the positive direction,
It is set so that a large voltage is generated in the negative direction at the falling signal when the wheel 1 finishes transferring from the platform 3 to the road surface 2 from the position β2, and during the period T, the platform 3
The setting is such that a large signal is not generated by fluctuation components caused by unevenness of the road surface 2 before and after the vehicle, individual differences in driving, etc.

As shown in FIG. 3(d), the first comparator circuit 8b detects that the output signal of the differentiator circuit 8a is equal to the reference value V, (voltage level +Vrar).
), the output becomes high level and is input to the set input terminal of the flip-flop circuit 8d. The set input terminal of the flip-flop circuit 8d is an input terminal that sets the output of the flip-flop circuit 8d to a high level when the signal level drops from a high level to a low level.

As shown in FIG. 3(e), the second comparator circuit 8c detects that the output signal of the differentiating circuit 8a is the reference value ■2 (voltage level -■r,
, f), the output becomes high level and is input to the reset input terminal of the flip-flop circuit 8d. The reset input terminal of the flip-flop circuit 8d is a terminal that resets the output of the flip-flop circuit 8d to low level when the signal level rises from low level to high level.

As described above, the flip-flop circuit 8d generates a pulse corresponding to the integration period T as shown in FIG. 3(f).

[Effect of the Invention 1 As explained above, the vehicle axle load measuring device according to the present invention can detect the integral period without being affected by differences in external dimensions of wheels, the size of the ground contact width, etc. The load signal is integrated at , and the load is calculated by dividing the integrated value by a signal proportional to the integration period, so it is not affected by road surface conditions or driving operation conditions like in the past. Vehicle axle load can be measured with high accuracy.

[Brief explanation of drawings]

Fig. 1 is a signal waveform diagram of the total load detected by the load sensor, Fig. 2 is a block diagram showing an embodiment of the vehicle axle load measuring device according to the present invention, and Fig. 3 is a waveform diagram of each part of the device. be. 1...wheels, 2--road surface, 3--mounting platform, 4,4°
...Load detector (load cell), 5...Load transmission mechanism, 6...Adder, 7...Amplifier, 8...Integration period generation circuit, 8a...Differential circuit, 8b...・First comparison circuit, 8c... Second comparison circuit, 8d... Flip-flop circuit, 9-... Integrator, 10-... Voltage generator, 11... Divider, 12-... ·display.

Claims (1)

[Claims] A platform whose upper surface is installed at the same height as the road surface, and a platform below the platform to generate signals of sizes corresponding to the loads applied to the front and rear in the vehicle passing direction. a plurality of load detectors arranged on the table, an adding circuit that adds up the load detection signals generated from the load detectors, and a signal corresponding to the time when the load is applied on the table in response to the added value signal. an integrator that integrates the added value over the time period; and a divider that divides the integrated value by a signal proportional to the time period to calculate the load applied to the table. A vehicle axle load measuring device characterized by comprising: