WO2022019422A1 - Vehicle load measuring apparatus for measuring load supported by axle, and method therefor - Google Patents

Abstract

Disclosed are a vehicle load measuring apparatus for measuring a load supported by an axle, and a method therefor. A load measuring apparatus according to the present invention may measure the amount of minute deformation when a part between two points of an axle is stretched while the axle of a freight vehicle equipped with a variable axle is deformed by the load weight. In addition, the present invention proposes an auto-calibration method to obtain a proportional constant K between the deformation amount of the axle and the axle load.

Description

Vehicle load measuring device and method for measuring load supported by axle

The present invention is an apparatus installed in a finished vehicle, and a device and method for measuring the load on the axle by measuring the amount of fine deformation when the axle between two points of the axle is tensioned while the axle of a freight vehicle with a variable axle is deformed by the load load. is about

Measuring the load imposed on the axle of a moving vehicle, especially a freight vehicle, is necessary for several reasons, including overload protection and variable axle control. There is a set standard for the load that can be supported per axle, and loading beyond the rating can cause vehicle damage or road damage. Article 77 of the Korean Road Act, Article 79 of the Enforcement Decree of the same Act, Article 39 of the Road Traffic Act and Article 22 of the Enforcement Decree of the same law limit the load to 40 tons in total weight and 10 tons per axle in consideration of road destruction and safety. However, in reality, since it is difficult for the driver of the freight vehicle to estimate the load loaded on the vehicle, the gross weight or the permissible load per axle is frequently violated.

One of the widely used methods to reduce the load per shaft is to use a variable shaft. A variable axle is a type of axle mainly used for medium-sized trucks. It is not a fixed axle to the chassis, but an axle that can be lowered and raised as needed. It is used as a method to solve the overload problem. The variable shaft is lowered and raised by the operation of Lift Air Bellows and Load Air Bellows. Air bellows are also called 'air spring' or 'air bag'. When the lift air bellows expands to a predetermined air pressure, the variable shaft rises. Conversely, when the load air bellows expands, the variable shaft descends to divide and support the loaded load. The lift air bellows 401 and the load air bellows 401 operate by a pneumatic circuit, and may be directly controlled by a driver or may be controlled automatically.

Measuring the load acting on the axle is necessary for various reasons, but it is also essential for controlling the variable axle, and various methods have been proposed. The methods involve various vehicle components placed on the path through which the load of the load is transmitted to the ground. When the vehicle is loaded by the load, the pressure between the leaf spring and the tire changes, the distance between the frame and the axle changes due to the deformation of the leaf spring, and the concentrated load and the spring and The load generated at the axle joint area changes, and the load load can be measured by measuring the change.

Among them, components with a large amount of deformation are easily deformed by internal forces and frictional forces transmitted in various directions. A typical example is a leaf spring. Because of the large deformation, it was widely used to measure the payload. For example, Korean Patent Application Laid-Open No. 10-2009-0073976 proposes a method of calculating a load by measuring the inclination of a suspension spring by a loaded load, and Korean Patent Application Laid-Open No. 10-1999-0004089 discloses a chassis and a spring How to install a load cell in the connection part is presented.

However, there is a problem that the change due to the load load is not linear because a large amount of deformation can cause a lot of hysteresis between the load and the deformation amount. The leaf spring also has a hysteresis phenomenon due to friction, and when there is a stopper, a large measurement error occurs because deformation no longer occurs under a load of a certain size or more. In addition, the device for recognizing the deflection of the freight vehicle spring is generally large in size, so it is not easy to install it under the chassis, and it is difficult to guarantee durability because it is recognized by a mechanical method. The method of directly installing the load cell on the spring also requires an expensive, large-capacity load cell, and it is difficult to guarantee durability against vibration and shock.

One of the vehicle components that deform under the load is the axle (or axle housing). Compared to other components, the axle has the highest rigidity and the least amount of deformation, and is slightly bent in the order of micrometers (㎛). Therefore, the hysteresis phenomenon is very small in the characteristic curve between the load and the amount of deformation in the lateral direction of the axle housing for the load of the load, and the deformation amount is not saturated in the elastic deformation section within at least 130% of the design allowable load of the axle, and the can be approximated Therefore, if you measure the amount of slight deformation of the axle housing, you can calculate a very accurate load.

If the theory used in the beam analysis is applied to the axle, the axle is deformed by the vertical (gravity direction) force and the horizontal force. Since the deformation due to the horizontal force is negligible compared to the vertical force, the axle can be said to be bent by the vertical force, and although it is a very small change, it has the characteristic of changing linearly with the load load.

The vertical force acting on the axle of a freight vehicle equipped with a multi-plate spring suspension is the payload. Referring to FIG. 1 , when the load (W) of the vehicle is transmitted to the axle through the plate spring coupling part, the straight tube axle is slightly bent, so that the upper part of the axle is compressed and the lower part is tensioned in micrometers. As an experiment, when a 10-ton weight is loaded into a 5-ton medium-sized freight vehicle, the vertical deformation of the driving axle is about 200 micrometers, and the deformation of the axle is linear in proportion to the loaded load. If it is possible to measure the amount of micro-deformation occurring on the axle while loading cargo or driving a vehicle, the load applied to the axle can be measured from the relationship between the load and the amount of deformation.

On the other hand, there have been conventional methods for measuring the amount of deformation of the axle. For example, Korean Patent Laid-Open Publication No. 10-2019-0080183 discloses a method of measuring the deformation of an axle using a strain gauge. However, since the strain gauge is a very fine and sensitive sensor, it must be fixed to the axle in a sufficiently stable state. Therefore, since it is very difficult to directly install the strain gauge in a vehicle that has already been manufactured and operated, the design of the axle itself needs to be changed so that the strain gauge can be installed. This is because the shape of the axle is not suitable for attaching the sensor, and there is a risk that the axle may be damaged during the sensor installation process. Korean Patent Application Laid-Open No. 10-2019-0080183 proposes a special type of axle for attaching a sensor.

In addition, German Patent Publication DE 10 2004 019 624 B3 (December 22, 2005) proposes a method for calculating a load with an axle load sensor. However, as shown in the corresponding patents FIGS. 4 to 6 , a method for measuring the strain in the spring element is presented.

[Related technical literature]

1. Republic of Korea Patent Publication No. 10-2019-0080183 (Axle-attached vehicle axle weight sensor module)

2. Korean Patent Laid-Open Patent No. 10-2009-0073976 (Apparatus and method for measuring vehicle load)

3. Republic of Korea Patent Publication No. 10-1999-0004089 (Truck load capacity measurement and confirmation device)

4. Republic of Korea Patent Publication No. 10-2013-0061904 (Sensor assembly device for monitoring axle weight of commercial vehicles)

5. Republic of Korea Patent Registration No. 10-0884233 (Vehicle load weight measurement device)

6. German Patent Publication DE 10 2004 019 624 B3 (Axle Load Measuring Device for Axles with Pneumatic and Mechanical Suspension)

An object of the present invention is to provide an apparatus for measuring the load on the axle by measuring the amount of fine deformation when the axle between two points of the axle is stretched while the axle of a freight vehicle equipped with a variable axle is deformed by the load load.

Another object of the present invention is to propose a method of obtaining the proportionality constant K of the first-order linear approximation between the vehicle load and the minute deformation of the axle in calculating the vehicle load as a method of measuring the amount of change in the axle.

In order to achieve the above object, the present invention provides a load measuring method of an axle load measuring device. The method of the present invention comprises the steps of changing a variable shaft load of a variable shaft in a tolerance state, changing an adjacent shaft load supported by an adjacent shaft adjacent to the variable shaft, and measuring an amount of axle deformation by a measuring terminal installed on the adjacent shaft in which the load is changed; A calculation unit calculates the variable shaft load using a pneumatic sensor installed on the variable shaft air bellows, reads the axle deformation amount from the measurement terminal, and calculates the proportional constant K between the axle deformation amount and the change amount of the adjacent axle load and calculating using the equation of

Wherein L2 is the distance between the front axle and the adjacent axle in a tolerance state, L4 is the distance between the front axle and the variable axle, ΔX is the axle deformation amount, and ΔWa is the change amount of the variable axle load, and the axle deformation amount is determined by the load on the adjacent axle It is possible to measure the size of the deformation caused by bending.

According to an embodiment, the method of the present invention may further include repeating the step of measuring the axle strain amount n times while repeatedly changing the variable shaft load. In this case, the calculator calculates the proportionality constant K based on the results of the n pairs of the variable axle load and the axle deformation obtained for each n-th repeating step.

According to another embodiment, the measuring method of the present invention may further include calculating, by the calculator, an adjacent axial load in a state in which the load is loaded. The calculator calculates the adjacent axle load by multiplying the proportional constant K by the axle deformation amount measured by the measuring terminal in a state in which the vehicle is loaded, and then adding the tolerance load of the adjacent axle.

According to another embodiment, in the measuring method of the present invention, when a first measuring terminal which is the measuring terminal is installed on the left side of the axle and a second measuring terminal which is the measuring terminal is installed on the right side of the axle, the The method may further include calculating, by a calculation unit, a proportionality constant Ka using the first measuring terminal in a tolerance state and calculating a proportionality constant Kb using the second measuring terminal. In this case, the calculating of the adjacent axial load may include a value obtained by multiplying an axle deformation amount provided by the first measuring terminal by the proportional constant Ka and a value obtained by multiplying an axle deformation amount provided by the second measuring terminal by the proportional constant Kb The adjacent shaft load is calculated by adding the tolerance load of the adjacent shaft to the average of .

According to another embodiment, the measuring terminal may measure the magnitude of tension in the axial direction when the axle is bent by a load. For example, the measurement terminal may include a first fixing part having one end fixed to one point of the axle, a second fixing part having one end fixed to another point of the axle, and spaced apart from the axle under the axle. It may include a measuring part connected between the first fixing part and the second fixing part in a state to measure the magnitude of the tension of the axle in the axial direction.

The present invention also extends to a vehicle load measuring device. The load measuring device of the present invention includes a pneumatic sensor installed on an air bellows of a variable shaft, and a measuring terminal installed on an adjacent shaft adjacent to the variable shaft (an axle capable of measuring a size among deformations occurring when the adjacent shaft is bent by a load) measuring one of the deformation amounts) and a calculation unit for calculating the proportionality constant K. The calculation unit calculates the variable shaft load using the pneumatic sensor in the tolerance state, reads the axle strain amount from the measurement terminal, and calculates the proportional constant K between the axle strain amount and the change amount of the adjacent shaft load using the above formula to calculate

The load measuring apparatus of the present invention can measure a minute amount of deformation when the axle of a freight vehicle equipped with a variable axle is deformed by a load load and tension between two points of the axle is made.

In addition, according to the present invention, by controlling the variable shaft, the proportional constant K between the deformation amount of the axle and the axle load can be obtained in a simple way. If it is a vehicle of the same type, the proportional constant corresponding to the slope of the first-order linear approximation formula between the vehicle load and the amount of micro-deformation of the axle will be similar. The proportional constant K for each vehicle can be obtained.

Conversely, even with the same vehicle model, the upper structure may be changed while the freight vehicle is changed to a special vehicle (wing body, tank lorry, forklift, etc.), and the changed upper structure affects the stiffness of the axle. Therefore, the load characteristic curve may be different compared to the amount of axle deformation after structural change. Even in this case, by applying the present invention, it is possible to easily obtain and correct the proportional constant K between the amount of deformation caused by the change of the vehicle's upper structure and the load.

1 is a view showing the change of the axle of the freight vehicle due to the loading load;

2 is a block diagram of an axle load measuring device for a vehicle according to the present invention;

3 is a schematic structural diagram of a vehicle provided for the explanation of the proportionality constant K;

4 is a flowchart provided for explaining a method of calculating a proportional constant K according to auto-calibration of the present invention;

5 is a view showing a measurement terminal according to an embodiment of the present invention, and

6 is a view showing a state in which the measurement terminal of FIG. 5 is installed on the axle.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

Referring to FIG. 2 , the vehicle load measuring apparatus 200 of the present invention includes a variable shaft 201 installed in a vehicle, a variable shaft controller 203 for controlling the variable shaft 201 , an air pressure sensor 205 , and at least one of measuring terminals 207a, 207b, and 207c and a calculation unit 210 .

The variable axis 201 is controlled by the variable axis controller 203 . The variable shaft 201 may be any conventional one, and as long as the magnitude of the load supported by the variable shaft 201 can be controlled in a plurality of steps according to the control of the variable shaft controller 203, either a manual control method or an automatic No matter the control method. The air pressure sensor 205 measures the air pressure of the air bellows ( FIGS. 4 and 401 ) of the variable shaft 201 and provides it to the calculation unit 210 , and the calculation unit 210 is the air pressure sensor 205 of the The load supported by the variable shaft 201 is calculated from the measured value.

The measurement terminals 207a, 207b, and 207c have the same configuration except that their installation positions are different. Hereinafter, the individual measurement terminals 207a, 207b, and 207c are denoted as 'measuring terminal 207' and described as a representative, except when used separately.

The measurement terminal 207 is installed on the axle 10 of the vehicle and measures the amount of deformation occurring in the axle 10 when a load is applied to the axle 10 . At this time, the amount of deformation of the axle to be measured may be any as long as it can measure the amount of deformation that occurs when the axle 10 is bent by a load.

For example, as shown in FIG. 1 , the distance between the two points P1 and P2 of the lower part of the axle 10 directly reflects the bending deformation of the axle 10 and is a measurement target. Alternatively, when the axle 10 is bent, the deformation in the vertical direction (gravity direction) may be measured or the degree of compression of the upper part of the axle 10 may be measured. A conventionally known load cell or strain gauge may be used to measure the amount of deformation of the axle 10 . A specific example of the measurement terminal 207 will be separately described below.

The measurement terminal 207 provides the measurement value to the calculator 210 . Communication between the measurement terminal 207 and the calculation unit 210 may use a CAN (controller area network) widely used as a vehicle communication means, or may use other conventional communication means.

For auto-calibration for calculating the proportional constant K of the measuring terminal 207, the measuring terminal 207 must be installed on the adjacent shaft 11 of the variable shaft 201. For example, if the variable shaft 201 is installed behind the rear shaft as in FIG. 3 , the adjacent shaft 11 becomes the rear shaft, and the measuring terminal 207 should be installed on the rear shaft. Hereinafter, identification number 11 is described and denoted as 'adjacent axis' or 'rear axis'.

In addition, the measurement terminal 207 may be installed on any axis among several axes of the vehicle, may be installed on each axis, or may be installed on the same axis in plurality. If the load on the front axle 15 of the vehicle is to be measured, it must be installed on the front axle 15 . In consideration of this point, when the measuring terminal 207 is installed on any one of several axles of the vehicle, it is preferable to install it on the adjacent shaft 11 adjacent to the variable shaft 201 .

The calculator 210 is connected to the air pressure sensor 205 and the measurement terminal 207, and performs auto-calibration to calculate the proportional constant K used for calculating the load of the vehicle using the variable shaft control, and the axle 10 of the vehicle. ) is used to calculate the vehicle's load.

Meanwhile, the calculator 210 may be connected to the variable axis controller 203 to directly control the variable axis 201 through the variable axis controller 203 , but this is not essential. If the user directly controls the variable shaft controller 203 , the calculator 210 controls the variable shaft by checking the air pressure of the air bellows of the variable shaft 201 using the air pressure sensor 205 . You can check the status.

Auto-calibration (calculation of proportionality constant K)

Hereinafter, auto-calibration of the present invention will be described with reference to FIGS. 1 to 4 . First, referring to FIG. 1 , the axle 10 is bent as the load of the vehicle changes, and the upper part of the axle 10 is compressed and the lower part is tensioned. Since the load applied to the axle and the deformation of the axle have a linear relationship within the rated payload range of the vehicle, the approximation of Equation 1 is established.

Here, W is the load supported by the axle, X ₀ is the distance between two points on the axle (P1, P2) before bending deformation occurs, and X is the two points of the axle when bending deformation occurs due to the load (P1, P2) ) is the distance between K is a proportional constant between the load (W) supported by the axle and the deformation (XX ₀ ) of the axle, which can be regarded as the elastic modulus of the axle. If the proportional constant K is known, the load supported by the corresponding axle can be calculated from the amount of deformation of the axle measured by the measurement terminal 207 .

In order to calculate the proportionality constant K, it must be possible to measure the amount of change in the load and the amount of deformation of the axle at the same time. The present invention proposes a method of obtaining the proportional constant K through variable shaft control without applying a mathematical method through analysis of the complex shape and structure of the axle housing, which is referred to as 'auto calibration' in the present invention.

First, for convenience of explanation, below, the load supported by the variable shaft is 'variable shaft load', the load supported by the front axle 15 of the vehicle is 'front axle load', and the adjacent shaft 11 of the vehicle supports The load is called the 'adjacent axial load'. The variable shaft 201 has a variable shaft load depending on the air pressure of the air bellows 401 . Since the variable shaft 201 is usually installed adjacent to a specific axle (mostly the rear axle) of the vehicle, if the variable shaft load is changed by controlling the variable shaft 201, the load on the adjacent shaft 11 adjacent to the variable shaft 201 is also change linearly.

In FIG. 3 , the adjacent shaft 11 is shown as the rear shaft adjacent to the variable shaft 201 . Referring to FIG. 3 , the adjacent axial load Wr can be calculated as in Equation 2 below.

Here, Wr is the load on the adjacent axle, L1 is the distance between the front axle 15 and the center of gravity of the vehicle in an empty state, L2 is the distance between the front axle 15 and the adjacent axle 11 in the empty vehicle, and L3 is the adjacent axle (11) is the distance between the variable shaft 201, L4 is the distance between the front shaft 15 and the variable shaft 201 (L4 = L2 + L3), Wf is the front shaft load, Wa is the variable shaft load, We is the tolerance is the vehicle's load. In Equation 2, since We, L1, and L2 are constants, it can be seen that the adjacent axial load Wr is inversely proportional to the variable axial load Wa by (L4/L2). We, L1, L2, and L4 in Equation 2 can be obtained by direct measurement. On the other hand, the variable shaft load (Wa) is generated by the air pressure (Wb) generated in the air bellows (401). When the air pressure (Wb) of the air bellows 401 is measured using the air pressure sensor 205, the variable shaft load (Wa) can be obtained through the chart (force versus air pressure) provided by the air bellows 401 manufacturer. . Alternatively, as a direct measurement method, the variable shaft load Wa may be obtained from the air pressure Wb of the air bellows 401 .

When changing the variable axial load (Wa), the change in the adjacent axial load (Wr), which is an adjacent axis, may be calculated through Equation (2). At this time, since the center of gravity of the vehicle hardly changes, the following Equation 3 can be obtained from Equation 2. Here, ΔWr is the amount of change of the adjacent axial load Wr, and ΔWa is the amount of change of the variable axial load Wa.

According to Equation 3, as the variable axial load Wa increases, the adjacent axial load Wr decreases, and conversely, the adjacent axial load Wr increases linearly as the variable axial load Wa decreases. Since the adjacent axial load (Wr) also changes when the variable axial load (Wa) is changed, Equations (1) and (3) are used to obtain the measured value (ΔX) of the measuring terminal 207 while changing the variable axial load (Wa). Therefore, the proportionality constant K can be obtained as in Equation 4 below. ΔX is the amount of deformation of the axle.

Calculation method of proportional constant K through variable axis control (Fig. 4)

Hereinafter, a method of obtaining the proportionality constant K according to the auto-calibration of the present invention will be described with reference to FIG. 4 . In a tolerance state where there is no other load in the vehicle, the calculator 210 measures the amount of change in the load on the adjacent axle and the deformation amount of the axle based on Equations 2 to 4 above, and calculates a proportional constant K. For convenience of explanation, assuming that the adjacent shaft 11 is the rear shaft with reference to FIG. 3 , the measurement terminal 207 for auto-calibration should be installed in the rear shaft, which is the adjacent shaft 11 .

<Initial variable shaft load in tolerance state: S401>

In the tolerance state in which there is no other load in the vehicle, the calculator 210 checks the 'initial variable shaft load' state. According to an embodiment, the calculator 210 initially descends the variable shaft 201 through the variable shaft controller 203 based on the air pressure Wb of the air bellows 401 measured by the air pressure sensor 205 . It is possible to create a variable-axis load or to check the initial variable-axis load state through the user's direct control.

When the variable shaft 201 descends to generate the variable shaft load Wa, the adjacent shaft load is reduced by that much. The initial variable shaft load can be set arbitrarily, but it should be the same as or less than the load on the adjacent shaft (eg, rear axle) in the tolerance state in which the variable shaft does not operate. This is because, if the initial variable shaft load exceeds the adjacent shaft load in the tolerance state, the adjacent shaft load becomes zero (0) and is lifted, and correlation cannot be obtained. The adjacent axial load or the initial variable axial load in the tolerance state may be preset in the calculator 210 as an initial set value.

<Reduction of variable axial load over nth order or increase of adjacent axial load: S403 to S407>

While repeatedly reducing the variable axial load (Wa) over the nth order, it is provided to the calculator 210, which calculates the variable axial load (Wa) by using the pneumatic sensor 205 and the measurement terminal Reference numeral 207 measures the amount of deformation of the axle whenever the variable shaft load Wa decreases and provides it to the calculator 210 . Here, n is a natural number where n>0. When the variable axial load Wa is reduced, the adjacent axial load proportionally increases according to Equation (3). Similarly, the calculator 210 may control the variable shaft load Wa based on the air pressure Wb of the air bellows 401 measured by the air pressure sensor 205 while controlling the variable shaft controller 203 . .

For example, assuming that the variable shaft load is reduced over the entire 3rd order (n = 3), if the variable shaft load (Wa) is first reduced by 300kg, the adjacent shaft load (Wr) is 300x(L4/L4/ L2) increases. If the variable shaft load Wa is reduced by 400 kg again, the adjacent shaft load Wr increases by 400x (L4/L2). Third, if the variable shaft load (Wa) is reduced by 500 kg, the adjacent shaft load (Wr) is increased by 500x (L4/L2).

On the other hand, although the magnitude of the decrease (increase of the adjacent shaft load) of the variable shaft load Wa in each step may be the same, it is preferable that they are different from each other. In the above example, the variable shaft load (Wa) is decreased to a larger value, but on the contrary, it is okay to decrease it to a smaller size.

<Calculation of proportionality constant K: S409>

The calculation unit 210 obtains the amount of change in the variable axle load and the amount of axle deformation measured by the measurement terminal ( ) for each adjustment of the variable axle load over the nth order (steps S403 to S407), and obtains the change amount of the variable axle load and the axle Calculate the proportionality constant K by applying the deformation amount result of Equation 4 to Equation 4.

First, the amount of change in the adjacent shaft load can be obtained through Equation (3). For example, when the (L4/L2) value is 1.2, it is assumed that the change amount (ΔWr) of the load on the adjacent axle and the amount of deformation of the axle measured at that time are as shown in Table 1 below.

step	Change in adjacent shaft load (ΔWr= -ΔWa x L4/L2)	Axle Deformation (distance, μm)
S403	-(-300 x 1.2) = 360	203
S405	-(-400 x 1.2) = 480	265
S407	-(-500 x 1.2) = 600	321

The calculation unit 210 obtains the proportionality constant K by introducing the measurement values of Table 1 to Equation 4, and may be calculated using a least square method. In Table 1 where (L4/L2) is 1.2, the proportionality constant K becomes 2.0321 (Kg/㎛). In the above method, it is possible to easily obtain the proportionality constant K between the amount of deformation of the axle with respect to the change in the vehicle load.

For the same type of vehicle, the proportional constant corresponding to the slope of the linear approximation between the load and the amount of micro-deformation will be similar. Therefore, the statistical proportional constant K can be obtained for each vehicle by measuring three or more vehicles of the same type.

Conversely, even with the same vehicle model, the upper structure may be changed while the freight vehicle is changed to a special vehicle (wing body, tank lorry, forklift, etc.), and the changed upper structure affects the stiffness of the axle. Therefore, it is possible to show a load characteristic curve compared to the amount of deformation different from before the change after the structural change. Even in this case, by applying the present invention, it is possible to easily obtain and correct the proportional constant K between the amount of deformation caused by the change of the vehicle's upper structure and the load.

In addition, the proportionality constant K can be calculated with different values for the position of the same axle, especially on the left and right. Since the housing of the axle has a complex shape with an asymmetric structure, and parts that transmit various driving forces are assembled therein, it is necessary to recalculate the proportionality constant K for each measuring terminal installed at different positions on the same axle.

Calculation of vehicle load

The calculation unit 210 calculates the load W of the vehicle in the loaded state using Equation 5 below. Here, Wro is the tolerance load of the adjacent axle and ΔX is the amount of deformation of the axle.

For example, when the proportional constant K is 2.0321 and the weight of the adjacent shaft during tolerance is 3000 kg, the adjacent shaft load may be calculated using the measurement value of the measuring terminal 207 . If the deformation amount (ΔX) of the adjacent axis measured by the measuring terminal 207 is 200㎛, the adjacent axis load is calculated as 3000+2.0321(kg/㎛) x 200 = 3406.42kg, and the adjacent axis deformation amount (ΔX) is measured as 400㎛ Then, the adjacent axial load is calculated as 3000+2.0321(kg/㎛) x 400 = 3812.84 kg. The calculator 210 may display 3410 kg and 3810 kg on a display unit (not shown) after rounding up to 10 digits in consideration of the error range and the user's visibility.

Furthermore, a more accurate load may be calculated by installing the first measuring terminal 207a and the second measuring terminal 207b on the left and right of the axle 10 to measure the amount of change in the axle from the left and right sides of the axle 10 . At this time, the proportionality constant in each measurement terminal 207 must be individually obtained using the method of FIG. When the first measurement terminal 207a is installed on the left side of the adjacent shaft and the second measurement terminal 207b is installed on the right side, the adjacent shaft load is as shown in Equation 6 below.

Here, the proportional constant of the first measuring terminal 207a is Ka, and the proportional constant of the second measuring terminal 207b is Kb. ΔXa is the amount of deformation of the axle measured by the first measuring terminal 207a, and ΔXb is the amount of deformation of the axle measured by the second measuring terminal 207b.

To this end, the calculator 210 may store and manage vehicle specification information, variable axis specification information, and variable axis control conditions. The vehicle specification information includes the load for each axle in the tolerance state, the distance between the axles, the vehicle weight, the maximum load capacity, the total vehicle weight, the shape of the variable shaft, etc., and the variable shaft specification information includes the specification information of the air bellows 401 applied to the variable shaft 201 and structural dimensions of the variable axis. The variable axle control conditions include the maximum design load per vehicle axle, the time of raising/lowering the variable axle, and the load distribution ratio between the adjacent axle and the variable axle. Some of this information may be entered by the user.

Example: Measuring terminal (measurement of the amount of deformation of the distance between two points of the axle)

The measuring terminal 207 is installed between two points in the transverse direction of the axle 10 to measure the amount of deformation in the lateral direction, and a measuring terminal 500 capable of measuring the lateral deformation is shown in FIG. 5 . has been Referring to FIG. 5 , the measuring terminal 500 includes a measuring unit 510 , a first fixing unit 530 , and a second fixing unit 550 .

The measuring part 510 is disposed to connect between the first fixing part 530 and the second fixing part 550 to measure the distance stretched in the transverse direction (transverse axis direction) of the axle shaft 10 . As described above, since any deformation of the axle 10 may be used for calculating the load, the measuring unit 510 does not need to be fixed in a specific direction with respect to the axle 10 or the horizontal plane.

In contrast to the first fixing part 530 and the second fixing part 550 being fixed to one side of the axle 10 , it is preferable that the measuring part 510 be installed to be spaced apart from the axle 10 . This is because the measurement unit 510 measures the size of the lower portion of the axle 10 tensioned by the load, and thus has an effect of amplifying the actual tensile size as it is spaced apart from the axle 10 that is actually bent and stretched.

As a measuring means of the measuring unit 510, an electric micrometer sensor or a load cell may be used. Among them, a load cell is a sensor assembly for measuring an object's load or external force, and a load sensing sensor ( sensor). When a load cell is used as the measurement unit 510, the movement of the internal measurement means is converted into an electrical signal by the strain gauge.

The measurement unit 510 includes a communication means connected to the calculation unit 210 and provides the measured value to the calculation unit 210 .

The first fixing part 530 and the second fixing part 550 connect the measuring part 510 to the first and second points (eg, P1 and P2 in FIG. 1 ) set at a relatively lower portion of the axle 10 . plays a role The first fixing part 530 and the second fixing part 550 may be implemented in various forms depending on the installation location.

In the example of FIG. 6 , the first point is set as the lower end of the U-bolt plate 61 that is the point of application of the vehicle load, and the second point is set as the lower end of the shock absorber 63 fixed to the axle 10. . One end of the first fixing part 530 is connected to the measuring part 510 and the other end is fixed to the first point by welding or the like. Similarly, one end of the second fixing unit 550 is connected to the measuring unit 510 and the other end is connected to the second point. The other end 551 of the second fixing part 550 is implemented in a ring shape to be connected to the shock absorber 63, which is the second point, and is fixed with a bolt.

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and it is common in the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Various modifications may be made by those having the knowledge of, of course, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

Claims (11)

1. In the method of measuring the load for a vehicle,

   Changing the variable shaft load of the variable shaft in the tolerance state to change the adjacent shaft load supported by the adjacent shaft adjacent to the variable shaft, and measuring the axle deformation amount by a measuring terminal installed on the changed adjacent shaft. the amount of deformation of the axle may be measured among deformations occurring when the adjacent axle is bent by a load; and

   A calculation unit calculates the variable shaft load using a pneumatic sensor installed on the variable shaft air bellows, reads the axle deformation amount from the measurement terminal, and calculates the proportional constant K between the axle deformation amount and the change amount of the adjacent axle load Comprising the step of calculating using the formula of

   

   Wherein L2 is a distance between the front axle and the adjacent axle in a tolerance state, L4 is a distance between the front axle and the variable axle, ΔX is an axle deformation amount, and ΔWa is a change amount of the variable axle load.
2. According to claim 1,

   The method further comprising repeating the step of measuring the axle deformation amount n times while repeatedly changing the variable axle load,

   The method of measuring the load for a vehicle, characterized in that the calculation unit calculates the proportionality constant K based on the results of the n pairs of the variable axle load and the axle deformation obtained for each n-th repeating step.
3. According to claim 1,

   the calculator

   Calculating the load on the adjacent axle in the loaded state by multiplying the amount of axle deformation measured by the measurement terminal by the proportional constant K in a state in which the vehicle is loaded and then adding the tolerance load of the adjacent axle to the vehicle A method of measuring the load for a vehicle, characterized in that.
4. 4. The method of claim 3,

   When the first measuring terminal which is the measuring terminal is installed on the left side of the axle and the second measuring terminal which is the measuring terminal is installed on the right side of the axle, the calculation unit uses the first measuring terminal in the tolerance state Calculating the constant Ka and using the second measurement terminal further comprising the step of calculating the proportional constant Kb,

   In the calculating of the adjacent axle load, the value obtained by multiplying the amount of axle deformation provided by the first measurement terminal by the proportional constant Ka and the value obtained by multiplying the amount of axle deformation provided by the second measurement terminal by the proportional constant Kb. A method for measuring a vehicle load, characterized in that the adjacent shaft load is calculated by adding the tolerance load of the adjacent shaft.
5. 5. The method according to any one of claims 1 to 4,

   The measuring terminal is a method for measuring a vehicle load, characterized in that for measuring the magnitude of the tensile force in the axial direction when the axle is bent by the load.
6. In the vehicle load measuring device,

   Air pressure sensor installed on the air bellows of the variable shaft;

   a measuring terminal installed on an adjacent shaft adjacent to the variable shaft to measure one of the axle deformation amounts that can measure the magnitude of deformation generated when the adjacent shaft is bent by a load; and

   In a tolerance state, the variable shaft load is calculated using the pneumatic sensor, the axle strain amount is read from the measurement terminal, and the proportional constant K between the axle strain amount and the change amount of the adjacent shaft load is calculated using the following equation including a calculation unit that

   

   Wherein L2 is a distance between the front axle and the adjacent axle in a tolerance state, L4 is a distance between the front axle and the variable axle, ΔX is an axle deformation amount, and ΔWa is a change amount of the variable axle load.
7. 7. The method of claim 6,

   The calculator is

   When the variable axle load is changed again in the tolerance state, the process of calculating the variable axle load using the pneumatic sensor and reading the axle deformation amount from the measurement terminal is repeated n times, and then n pairs of the variable axle loads and the load measuring device for a vehicle, characterized in that the proportional constant K is calculated based on the result of the deformation of the axle.
8. 8. The method of claim 7,

   The calculator is

   In a state in which the load is loaded in the vehicle, the load on the adjacent axle is calculated by multiplying the amount of axle deformation measured by the measurement terminal by the proportional constant K and then adding the tolerance load of the adjacent axle. Axle load measuring device.
9. 9. The method of claim 8,

   When the first measuring terminal, which is the measuring terminal, is installed on the left side of the axle, and the second measuring terminal, which is the measuring terminal, is installed on the right side of the axle, the calculation unit is the first measuring terminal when the calculation unit is in an tolerance state Calculate the proportionality constant Ka using

   The adjacent axle load in the loaded state is an average of a value obtained by multiplying the amount of axle deformation provided by the first measurement terminal by the proportional constant Ka and the value obtained by multiplying the amount of axle deformation provided by the second measurement terminal by the proportional constant Kb Axle load measuring device, characterized in that calculating the adjacent shaft load by adding the tolerance load of the adjacent shaft.
10. 10. The method according to any one of claims 7 to 9,

    The measuring terminal is an axle load measuring device, characterized in that for measuring the tensile strength in the axial direction when the axle is bent by a load.
11. 11. The method of claim 10,

    The measuring terminal;

    a first fixing part having one end fixed to one point of the axle;

    a second fixing part having one end fixed to another point of the axle; and

    Axle load measuring device, characterized in that it comprises a measuring part that is connected between the first fixing part and the second fixing part in a state spaced apart from the axle under the axle to measure the magnitude of the tension of the axle in the axial direction. .

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