JP4149874B2 - Construction machine load measuring device - Google Patents

Description

  The present invention relates to a load measuring device for a construction machine, and more particularly to a load measuring device for a construction machine suitable for improving the accuracy of dump truck load measurement.

  In a mine or quarry site, it is desirable to be able to measure the amount of mined material loaded on a dump truck. This is to prevent overloading by monitoring the load amount when loading onto the dump truck, and to prevent the dump truck from being damaged, and by recording the loading amount for each truck, It is for managing. For this purpose, depending on the site, a scale for weighing the truck may be installed to sequentially measure the weight of the truck in the loaded state, and the difference from the weight of the truck in the empty state measured in advance. The method of calculating the amount of cargo from the above has been taken. However, in this method of measuring, in addition to the personnel required for measuring and measuring, the truck must always move to the measuring place, which is an obstacle to increasing the productivity of dump trucks. It was. For this reason, there has been an increasing demand for a payload that allows the dump truck itself to have a load measurement function.

  As one form of the payload of the dump truck, there is a method of calculating a load from a pressure applied to a suspension that supports a body as a loading unit. When a hydraulic cylinder consisting of sealed gas and oil is used for the suspension, the pressure of this cylinder fluctuates as the load increases or decreases. Therefore, the measuring device can calculate the load by measuring the pressure of this suspension cylinder with a sensor. It becomes possible. This method is generally widely used because the apparatus can be constituted by relatively inexpensive devices such as a pressure sensor and a measuring device.

  However, the payload of the dump truck is affected by the posture of the vehicle body and the state of the suspension cylinder. Therefore, for example, as described in Patent Document 1, there is known a method for improving the load measurement accuracy at the time of loading by reducing the influence such as the load balance and the inclination of the ground. However, when the cylinder is stopped during loading, the influence of the static frictional resistance of the cylinder is large, so an error is likely to occur in the relationship between the measured cylinder pressure of the suspension and the load load, which is inconvenient in managing the production volume. May be.

  Therefore, for example, as described in Patent Document 2 and Patent Document 3, in order to attenuate the influence of the pressure bias caused by the frictional resistance of the cylinder of the suspension, the cylinder pressure during traveling in which the cylinder vibrates up and down is reduced. A method using an average value is known.

Japanese Patent No. 2719328

JP-A-60-161532 JP-A-6-221902

  However, as described in Patent Document 1, Patent Document 2, and Patent Document 3, in the method of measuring the load by the cylinder pressure of the suspension, the suspension is not intended for load measurement, so the measurement accuracy is improved. Has many factors to influence. In the conventional method, the load amount is obtained by measuring the load in the loaded state and subtracting the load in the unloaded state based on the design value of the weight of the vehicle body.For example, the pressure due to leakage of gas sealed in the cylinder is calculated. The load in an empty state also changes due to a decrease or a change in the frictional resistance of the cylinder due to deterioration over time. There is also a problem that the load in an empty state changes due to earth and sand adhering to the body.

  An object of the present invention is to provide a load measuring device for a construction machine that can perform load measurement with high accuracy.

(1) In order to achieve the above object, the present invention measures the pressure of a body on which a load is loaded and a plurality of suspension cylinders that support the body of a construction machine, and the pressure measuring means. In a load measuring device for a construction machine having a load measuring means for calculating a load from a pressure value, a work determining means for determining a work state of the construction machine, and when the determination means determines that the load is empty, the load A load amount storage means for accumulating and storing an empty load We calculated by the measuring means , a difference between the empty load We and an empty load correction amount Wo in an empty state used for obtaining the loading amount is predetermined. If the value is equal to or greater than the value, load correction means for replacing the empty load correction amount Wo with the empty load We is provided, and the load measuring means determines that the construction machine is in a loaded state by the work determination means. The load load Wt is measured, and the load amount storage means stores and stores the load load Wt, and the load correction means stores the load load Wt and the empty load stored and stored in the load amount storage means. When there is a long-term proportional correlation with the change in We, the coefficient of the relational expression used when calculating the load by the load measuring unit from the pressure value measured by the pressure measuring unit is corrected, and the load In the case where there is no long-term proportional correlation between the load load Wt accumulated and stored in the quantity storage means and the empty load We, the empty load correction quantity Wo is stored in the load quantity storage means. It replaces with We .
With this configuration, load measurement with high accuracy can be performed.

( 2 ) In the above ( 1 ), preferably, the load correcting means is adapted to correct a load stored and stored.

  According to the present invention, there is provided a load measuring device for a construction machine capable of measuring a load with high accuracy.

Hereinafter, the configuration and operation of a load measuring apparatus for construction machinery according to an embodiment of the present invention will be described with reference to FIGS. The following example demonstrates the example which applied the load measuring device of the construction machine to the dump truck.
First, the configuration of the dump truck to which the load measuring device according to the present embodiment is applied will be described with reference to FIG.
FIG. 1 is a side view showing a configuration of a dump truck to which a load measuring device according to an embodiment of the present invention is applied.

  The dump truck shown in FIG. 1 operates at a large-scale site such as a mine or a quarry site. For example, the dump truck has a vehicle weight of 80 t and a loading weight of about 80 t. A body 2 for carrying a load is mounted on the body 1 of the dump truck. When the operator operates the body operation lever to operate the body operation cylinder 3, the body 2 can be woken up from the position of the solid line to the state indicated by the alternate long and short dash line. Can be unearthed. The body 1 of the dump truck is provided with a plurality of suspensions 4 that support the body on the front and rear axles. The load of the body 1 including the body 2 and the earth and sand mounted on the body 2 is applied to each suspension 4. That would be the case. Each suspension 4 has a pressure sensor attached to each cylinder in order to measure the cylinder pressure of the suspension 4 as a device for measuring the load of the load. These sensor signals are sent to a load measurement processor that calculates the load.

Next, the configuration of the load measuring device for the construction machine according to the present embodiment will be described with reference to FIG.
FIG. 2 is a system block diagram showing the configuration of the load measuring device for a construction machine according to one embodiment of the present invention.

  To the processing device 10 of the load measuring device, cylinder pressure sensors 5a, 5b, 5c, 5d attached to the respective cylinders are connected in order to measure the cylinder pressure of the suspension. In the example shown in FIG. 1, the vehicle body is supported by four suspensions, and four pressure sensors 5 are provided. Further, a transmission shift gear position signal 6, a vehicle body speed signal 7, and a state signal of the body raising / lowering operation lever 8 are input to the processing device 10 as vehicle body operation signals. Vehicle operation signals such as pressure signals from the cylinder pressure sensors 5a, 5b, 5c, 5d, transmission shift gear position signal 6, vehicle speed signal 7, body lift control lever 8 status signal are input via the input interface 16. It is taken into the processing device 10. The shift gear position signal, the vehicle body speed signal, and the body lifting / lowering state signal may be obtained by communication from another controller that controls the transmission and the body.

  The processing device 10 includes a CPU 11 that performs calculation, a timer 12 that drives the CPU 11, a clock 13 that acquires time, a ROM 14 that stores various processes (programs), and load that is a result of variable values and load measurement. It has a RAM memory 15 that stores data, an input interface 16 that performs sensor input and communication, and an output interface 17 that outputs a calculation result of the CPU 11 to a display device and an external device. Further, the processing device 10 can display the load amount on the display device 20 via the output interface 17, and can notify the load amount to the operator in the cab or the loader.

  The CPU 11 executes various processes (programs) stored in the ROM 15. These processes include a load measurement process S1, a work determination process S2, a load storage process S3, a load correction process S4, and an accumulated data correction process S5, and the contents of each process will be described below.

  In the load measurement process S1, the processing apparatus 10 reads the output signals of the cylinder pressure sensors 5a,..., 5d of the suspension at a predetermined sampling period and calculates the load. The total load calculated by the four cylinder pressure sensors 5a,..., 5d is the total load. This load is all the loads applied to the suspension including the vehicle body 01 and the body 02 in the load. This load measurement process is always performed regardless of whether or not there is a load.

  The load Wp of the load is the corrected load W0 in the empty state corrected from the measured load value Wt calculated from the cylinder pressure value in the loaded state by the empty load measured value We calculated from the cylinder pressure value in the empty state. Is calculated by subtracting.

  Conventionally, the load Wp has been obtained by subtracting the correction load Wo in the empty state based on the design value of the vehicle body weight from the load measurement value Wt in the loaded state. However, for example, the load in an empty state changes due to a decrease in pressure due to leakage of gas sealed in the cylinder, or a change in the frictional resistance of the cylinder due to aging, etc. In addition, the load of the empty body changed.

  Therefore, in this embodiment, the empty load measurement value We in the empty state is measured, the correction load W0 is corrected by this empty load measurement value We, and the correction load W0 is subtracted from the load measurement value Wt in the loaded state. Thus, the load Wp of the load is calculated.

Next, processing contents of the work determination process S2 in the load measuring device for construction machine according to the present embodiment will be described with reference to FIG.
FIG. 3 is a state transition diagram of the work determination process S2 in the load measuring device for the construction machine according to the embodiment of the present invention. FIG. 3 describes in UML (Unified Modeling Language unified modeling language) the transition of the work state of the dump truck and the load measurement calculation timing performed at the time of the transition.

  In the work determination process S2, the processing device 10 dumps from the load value Wp calculated in the load measurement process, the vehicle body speed signal 7, the shift gear position signal 6, and the state signal of the body operation lever 8 which is the body ascending / descending state. Judge the work of the truck.

  Here, for convenience of explanation, it is assumed that the process starts from the empty load movement S21. When the dump truck is moving in an empty state, in this embodiment, the load We in an empty state is repeatedly measured at a predetermined timing by the load measurement process S1. Therefore, in an always empty state, the load We at that time is measured and stored in the RAM 15.

  Here, as described above, the load in an empty state changes due to a decrease in pressure due to leakage of the gas enclosed in the suspension cylinder 4 and a change in frictional resistance of the cylinder due to deterioration over time. Thus, when an error occurs in the relational expression between the cylinder pressure and the load, it is necessary to correct the coefficient of the relational expression between the cylinder pressure and the load with a certain frequency. In addition, the empty load may change due to earth and sand adhering to the body.

  The load correction S25 is called by making a correction request when the measured empty load We deviates by more than a specified value with respect to the correction load Wo determined in advance by the vehicle body design load or the like. Here, the specified value is, for example, −5% to + 10%. That is, when the measured empty load We falls outside the range of 0.95 × correction load Wo to 1.1 × correction load Wo, a correction request is made. The reason why the range of the specified value is increased to the plus side is that the adhesion of earth and sand to the body is taken into consideration. The processing content of the load correction S24 is executed by a load correction processing S4 described later. When the correction load Wo is corrected by the empty load We, the corrected value is used as a new correction load Wo in subsequent processing.

  The transition from the empty state S21 to the loading state S22 is performed when it is determined that loading has started.

  The processing apparatus 10 can determine that loading is started when the load increases by a certain amount during the stop. The processing device 10 always displays the current loading amount Wp on the display device 20 mounted inside the cab or outside the vehicle during loading. The loading amount Wp is calculated by subtracting the correction load Wo from the load measurement value Wt during loading. Although the unloaded load We is measured while moving in an unloaded state, the measured value We varies depending on the state of unevenness of the traveling road surface, the inclination of the road surface, presence / absence of acceleration / deceleration during traveling, and so on. It is not suitable for use in determining the amount Wp. Therefore, the loading amount Wp (= Wt−Wo) is calculated using the correction load Wo determined in advance by the design load of the vehicle body or the correction load Wo obtained by correcting the correction load Wo in the load correction process S25. Like to do.

  The transition from the loading state S22 to the state of the load movement S23 is performed when loading completion is determined. The processing device 10 can determine that loading has been completed when the travel starts or when the processing device 10 moves a certain distance or more. When it is determined that the loading is completed, the processing device 10 stores the load measurement value calculated when the loading is stopped in the RAM 16 as a loading amount.

  Next, the transition from the load movement S23 to the earth release S24 is performed when the vehicle is moved backward. At the time of earth dumping to the hopper by the dump truck, the dump truck directs the back to the hopper and then moves backward so that the body 2 is brought close to the hopper 30 for earth dumping. Therefore, the transition from the load movement S23 to the earth release S24 can be performed when the vehicle is moved backward.

  In addition, even if it changes to the state of earthmoving S24, when it advances ahead more than a fixed distance without earthing, it will judge that the processing apparatus 10 was not reverse for earthing, and the state of cargo movement S23 Return to. The determination that there is no earth release can be made based on a signal from the body operation lever 8 that the body of the dump truck has not risen. In addition, it can replace with the presence or absence of a raise of a body, and it can also be judged that there is no earth discharge even if the load measurement value Wt has not decreased more than a fixed value.

  When it is determined that the earthing has been completed in the state of the earthing S24, the state changes from the earthing S24 to the empty load movement S21 again. The end of the earthing can be determined by a signal from the body operating lever 8 that the body of the dump truck is seated. In addition, it can be determined that the earthing is finished even when the loading amount Wp is close to zero (0 t ± 10%) instead of the body seating.

  The load amount storage process S3 stores the load measurement value calculated by the work determination process S2 in the RAM memory 16. As the load measurement value, the load measurement value at the completion of loading and the load measurement value in an empty state are stored. The start time and end time of a series of operations from the unloading to the unloading are simultaneously stored as a clock time stamp, and the distance and time of the unloading movement and the distance and time of the loading movement are recorded in the same manner. These data are added to the RAM memory 16 every time a series of operations from unloading to releasing is completed.

Here, the content of the load measurement value data stored in the load measuring device for the construction machine according to the present embodiment will be described with reference to FIG.
FIG. 4 is an explanatory diagram of load measurement value data stored in the load measurement device for a construction machine according to an embodiment of the present invention.

  As shown in FIG. 4, stored data T01 includes start time, end time, total weight Wt, empty load We, correction load W0, load load Wp, empty load movement distance, load It consists of the distance traveled. The start time and the end time are a start time and an end time of a series of work from the unloading movement to the earthing, respectively. The load Wp is obtained by subtracting the correction load W0 from the total weight Wt. The empty load moving distance is a moving distance when it is determined that the empty load moving S21 in FIG. The load moving distance is a moving distance from the completion of loading until the load is moved and released.

Next, the contents of the load correction process S4 in the load measuring device for construction machine according to the present embodiment will be described with reference to FIG.
FIG. 5 is a flowchart showing the processing content of the load correction processing S4 in the construction machine load measuring device according to the embodiment of the present invention.

  The load correction process S4 is called every time the data stored and stored by the load amount storage process S3 is stored and stored.

  In Step F10, the empty load We is compared with the current empty load correction amount Wo, and it is determined whether or not this difference (We−Wo) exceeds a specified value over a certain period of past storage and storage. judge. Here, the past certain period is, for example, a period of one week or two weeks. The specified value is, for example, −5% to + 10%. That is, when the measured empty load We is out of the range of 0.95 × correction load Wo to 1.1 × correction load Wo over a certain period in the past, the process proceeds to step F20. If not, the process is terminated. Here, even if the difference (We-Wo) exceeds the specified value, the period is short, and if the specified value has not been exceeded for a certain period of past storage and storage, the processing is terminated. In this case, the load measurement value fluctuates temporarily due to the body ascending / descending operation, the load measurement value fluctuates temporarily due to load bias, or the load measurement value due to the friction resistance of the suspension cylinder. This is the case when fluctuates temporarily.

Here, for reference, an example of changes in the empty load We and the load Wt will be described with reference to FIG.
FIG. 6 is an explanatory diagram showing an example of changes in the empty load We and the load load Wt in the load measuring device for a construction machine according to an embodiment of the present invention. In FIG. 6, the horizontal axis indicates the number of measurements, the vertical axis indicates the empty load correction amount Wo (t), the reference B indicates the empty load We (t), and the reference C indicates the load Wt (t). ).

  As shown in the figure, when the empty load We is compared with the current empty load correction amount Wo, this difference (We-Wo) exceeds the specified value over a certain period of past storage and storage. In addition, it is determined that the difference (We−Wo) exceeds the specified value.

  If the difference (We-Wo) exceeds the specified value, it is determined in step F20 whether there is a proportional correlation between the empty load We and the load Wt for a certain period, and there is a proportional correlation. Advances to Step F30, and if there is no proportional correlation, advances to Step F40.

Individually, the proportional correlation between the empty load We and the load Wt will be described with reference to FIG.
FIG. 7 is an explanatory diagram showing the presence or absence of a proportional correlation between the empty load We and the load Wt in the construction machine load measuring apparatus according to an embodiment of the present invention. 7A shows a case where there is a proportional correlation, and FIG. 7B shows a case where there is no proportional correlation.

  Here, the maximum load amount Wstd is an average load amount in the load state at the site or the maximum load amount of the dump truck. The representative load value We (av) in an empty state is used for determining a difference from a specified value, and is an average value or a mode value of the empty load We during a certain period. Further, the representative load value Wt (av) in the loaded state is an average value or a mode value of the loaded load Wt for a certain period.

  In general, when the temperature of the cylinder oil in the suspension changes due to the climate, or when the gas in the cylinder leaks and the pressure in the cylinder decreases, the error increases in proportion to the weight of the load applied to the cylinder. In this case, as shown in FIG. 7A, the ratio (representative load value We (av) in the unloaded state / empty correction amount Wo) is equal to the ratio (representative load value We (av in the unloaded state). ) / Maximum load amount Wstd), and such a case is referred to as “having a proportional correlation” with respect to the load.

  On the other hand, if a change in the vehicle body weight applied to the cylinder due to the additional mounting on the vehicle body or a decrease in frictional resistance due to wear of the cylinder bush occurs, the weight of the load applied to the cylinder and the error are not proportional. In such a case, as shown in FIG. 7B, the difference (representative load value We (av) in the unloaded state−empty load correction amount Wo) and the difference (representative load value We in the unloaded state). (av) −maximum load amount Wstd) is approximated. Such a case is referred to as “no proportional correlation” with respect to the load.

If there is a proportional correlation, the load calculation coefficient is corrected as follows in step F30.
The relational expression for measuring the load W from the cylinder pressure P is simply expressed by the following expression (1).

W = K · f (P) + C (1)

Here, K and C are constants.

When there is a proportional correlation, the proportional coefficient K in Formula (1) includes an error. Therefore, a relational expression represented by the following expression (2) between the representative value We (av) and the pressure Pe in an empty state,

We (av) = K · f (Pe) + C (2)

In contrast, a new proportionality coefficient K ′ that satisfies the following expression (3) is obtained.

Wo = K ′ · f (Pe) + C (3)

That is, from the equation (2) and the equation (3), the following equation (4):

K ′ = K · (Wo−C) / (We (av) −C) (4)

A new correction coefficient K ′ is obtained, and thereafter, the error can be reduced by calculating a load measurement value from the cylinder pressure using the new correction coefficient K ′.

  On the other hand, if there is no proportional correlation between the empty load We and the loaded load Wt, the empty load correction amount Wo is replaced with the measured empty load We in step F40. The case where there is no proportional correlation between the unloaded load We and the unloaded load Wt is a case where the unloaded load We and the unloaded correction amount Wo tend to deviate. For example, the body liner is lined on the body. In this case, the empty load correction amount Wo itself is different from a value determined in advance by the design load of the vehicle body. In such a case, the empty load We is set as the correction load Wo. By doing so, the error between the empty load correction amount Wo and the empty load We can be reduced. Further, even when earth and sand remain attached to the body for a long period of time, no proportional correlation is observed between the empty load We and the load Wt.

Further, when there is no proportional correlation, the constant C in the equation (1) includes an error. Therefore, instead of replacing the empty load correction amount Wo with the empty load We, it is also possible to correct as follows. That is, when there is no proportional correlation, a new constant C ′ that satisfies the following expression (5) is obtained for expression (2).

Wo = K · f (Pe) + C ′ (5)

That is, from the formula (2) and the formula (5), the following formula (6):

C ′ = C− (We (av) −Wo) (6)

A new constant C ′ is obtained, and thereafter, the error can be reduced by calculating a load measurement value from the cylinder pressure using the new constant C ′.

  The processing device 10 may be configured to record only the load measurement values and record the recorded load measurement values on a memory card or the like. Then, the load measurement value recorded in the memory card is read out by an external management device, the load calculation coefficient is corrected using the pre-registered empty load data, and the empty load correction amount Wo is calculated. The load may be changed to calculate the load.

  In the above method, a new correction coefficient K ′ and a constant C ′ are obtained. However, the ratio (We / Wo) is corrected using a correction value table prepared in advance. Is also good.

  Here, a correction method using the correction value table will be described with reference to FIG. FIG. 8 is an explanatory diagram of a correction value table used in the load measuring device for a construction machine according to an embodiment of the present invention. FIG. 8A shows a correction value table for the correction coefficient K in equation (1), and FIG. 8B shows a correction value table for constant C in equation (1).

  8 (A) and 8 (B), the vertical row indicates the value (We / Wo) of the load We in the empty state and the load correction amount Wo, and the horizontal row indicates the load Wt and the load in the loaded state. The value of the ratio (Wt / Wstd) to the average load amount Wstd in the state is shown.

When there is a proportional correlation between the unloaded load We and the loaded load Wt, the corresponding numerical value Tk is extracted from the ratio (We / Wo) and ratio (Wt / Wstd) values using the table in FIG. And according to the following equation (7):

K ′ = K / Tk (7)

A new correction coefficient K ′ is obtained.

When there is no proportional correlation between the empty load We and the load Wt, the corresponding numerical value Tc is calculated from the ratio (We / Wo) and ratio (Wt / Wstd) values using the table of FIG. Is extracted from the following equation (8):

C ′ = C + Tc · Wo (8)

A new constant C ′ is obtained.

  For example, when the ratio (We / Wo) = 1.2 and the ratio (Wt / Wstd) = 1.1, the numerical value Tk = 1.2 and the numerical value Tc = 0, and only the correction coefficient K is K '= K / 1.2 will be corrected.

  If the method using the correction table is used in this way, in the field where the load Wt in the loaded state has a large fluctuation every time, the numerical value Tk is set so as to reduce the influence of Wt / Wstd. It becomes easy to do.

  Note that the representative load value We (av) in the empty state is used in place of the load We in the empty state in the vertical row, and in the loaded state in place of the load Wt in the loaded state in the horizontal row. The representative load value Wt (av) may be used.

Next, the contents of the accumulated data correction processing S5 in the construction machine load measuring apparatus according to the present embodiment will be described with reference to FIG.
FIG. 9 is a flowchart showing the contents of the accumulated data correction process S5 in the load measuring device for construction machine according to the embodiment of the present invention.

  In the load correction process S4, when the correction of the coefficient or the correction of the empty load correction amount is performed, the accumulated data correction process S5 corrects the already accumulated data with respect to the load storage accumulated data T1.

  In step G1 in FIG. 9, a section in which the difference between the empty load We stored in the accumulated data T1 and the empty load correction amount Wo is continuously greater than or equal to a specified value is detected.

  Then, in step G2, it is determined whether or not the corresponding section has been detected. If it cannot be detected, the correction process ends.

  When the corresponding section is detected, in step G3, the representative load We (av) of the empty load and the representative load Wt (av) of the load are calculated from the empty load We and the load Wt included in the section Ic, respectively. To do. Then, the correction coefficient K ′ and the correction constant C ′ are calculated using the correction table shown in FIG.

  Next, in step G4, it is determined whether or not all the processes included in the section Ic have been completed. The processes G1 to G3 are repeated until all the processes are completed, and when all the processes are completed, the process proceeds to step G5.

In Step G5, a corrected load W't [n] is calculated for each load Wt [n] included in the section Ic. The subscript [n] indicates the number included in the section IC. The value of the function f (Pt) when the cargo load Wt is calculated can be calculated from the equation (1):

f (Pt) = (Wt−C) / K (9)

As required. Formula for calculating the load after correcting equation (9)

W′t = K ′ · f (P) + C ′ (10)

By substituting into, the corrected total weight is obtained from the known coefficients K and C, the corrected coefficients K ′ and C ′, and the load Wt stored in the accumulated data as shown in the following equation (11). ,

W′t [n] = K ′ · (Wt [n] −C) / K + C ′ (11)

A load correction value W ′ [n] can be calculated. In the equation (11), the correction value W′t can be obtained even if the pressure Pt at the time of load measurement is not stored, so that the RAM area of the apparatus is not affected.

  Finally, in step G6, the load correction value W't [n] is stored in the accumulated data T1 in place of the load Wt before correction.

  The accumulated data correction process may be executed inside the processing apparatus 10 of FIG. 2 mounted on the vehicle body. If the load Wt is collected and stored wirelessly, the accumulated data is accumulated. It may be performed on the data.

  In this way, by retroactively correcting the accumulated data, the production volume can be managed with high accuracy when the production volume is managed from the accumulated data.

As described above, according to the present embodiment, the load amount in the empty load is accumulated and stored for each series of operations of the dump truck from the unloading movement to the loading and the unloading, and the long-term load of the empty load is determined. A highly accurate load measurement value can be obtained by correcting the relational expression for load measurement according to a simple change. Further, with this correction, the stored loading amount is corrected, and the production amount can be managed with high accuracy.

It is a side view showing composition of a dump truck to which a load measuring device by one embodiment of the present invention is applied. It is a system block diagram which shows the structure of the load measuring device of the construction machine by one Embodiment of this invention. It is a state transition diagram of work determination processing S2 in the load measuring device for construction machine according to one embodiment of the present invention. It is explanatory drawing of the load measurement value data preserve | saved in the load measuring device of the construction machine by one Embodiment of this invention. It is a flowchart which shows the processing content of the load correction | amendment process S4 in the load measuring device of the construction machine by one Embodiment of this invention. It is explanatory drawing of an example of the change of the empty load We and the load Wt in the load measuring device of the construction machine by one Embodiment of this invention. It is explanatory drawing of the presence or absence of the proportional correlation of the unloaded load We and the loaded load Wt in the load measuring device of the construction machine by one Embodiment of this invention. It is explanatory drawing of the correction value table used in the load measuring device of the construction machine by one Embodiment of this invention. It is a flowchart which shows the processing content of the accumulation | storage data correction process S5 in the load measuring device of the construction machine by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle body 2 ... Body 3 ... Body operation cylinder 4 ... Suspension cylinder 5 ... Cylinder pressure force sensor 6 ... Shift gear position 7 ... Vehicle body speed 8 ... Body operation lever 10 ... Processing device 20 ... Display device S1 ... Load measurement processing S2 ... Work determination Processing S3: Load amount storage processing S4: Load correction processing S5: Accumulated data correction processing

Claims (2)

Pressure measuring means for measuring the pressure of a plurality of suspension cylinders that support the body on which the load is loaded and the vehicle body of the construction machine;
In the load measuring device of the construction machine having the load measuring means for calculating the load from the pressure value measured by the pressure measuring means,
Work determination means for determining the work state of the construction machine;
A load amount storage means for accumulating and storing the empty load We calculated by the load measuring means when the work determination means determines that the load is empty ;
When the difference between the unloaded load We and the unloaded correction amount Wo in the unloaded state used for obtaining the loading amount is a predetermined value or more, a load correction for replacing the unloaded load amount Wo with the unloaded load We. With means,
The load measuring means measures a load Wt when the construction machine is determined to be in a loaded state by the work determining means, and the load amount storing means accumulates and stores the load load Wt,
The load correcting means is
When there is a long-term proportional correlation between the load load Wt accumulated and stored in the load amount storage means and the empty load We, the load measurement means uses the pressure value measured by the pressure measurement means. Correct the coefficient of the relational expression used when calculating the load,
When there is no long-term proportional correlation between the load load Wt accumulated and stored in the load amount storage means and the empty load We, the empty load correction amount Wo is stored in the load amount storage means. A load measuring device for a construction machine, wherein the load is replaced by a load We . In the load measuring device of the construction machine according to claim 1 ,
A load measuring device for a construction machine, wherein the load correcting means corrects a load stored and stored.

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