JP2005043267A - Load-measuring device of construction equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load measuring device of construction equipment, capable of accurately measuring load by measuring the load at timing at small effects of running state or state of ground surface. <P>SOLUTION: A pressure sensor 5 measures the pressure of a plurality of suspension cylinders supporting the body of a dump truck. In the load measuring processing S1 in a processor 10, the load of cargo is calculated from the pressure value measured with the pressure sensor 5. In work deciding processing S2, the load is measured and the measured value is recorded based on the operation signal for operating the vehicle body and the speed signal of the vehicle body, in the work state of construction equipment which can reduce the effects of the swinging of the car body and the frictional resistance of a cylinder, for example during moving forward and backward for discharging of soil. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

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 Japanese Patent No. 2719328, there is known a method for improving the load measurement accuracy at the time of loading by reducing the influence of 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. May be.

  Therefore, as described in, for example, Japanese Patent Application Laid-Open No. 60-161532 and Japanese Patent Application Laid-Open No. 6-221902, in order to attenuate the influence of pressure deviation caused by the frictional resistance of the cylinder of the suspension, the cylinder is moved up and down. There is known a method using an average value of the cylinder pressure during traveling that vibrates rapidly.

Japanese Patent No. 2719328 JP-A-60-161532 JP-A-6-221902

  However, as described in Japanese Patent Application Laid-Open No. 60-161532 and Japanese Patent Application Laid-Open No. 6-221902, the following problems arise in the method of measuring the load during normal traveling. In other words, during normal load traveling, whether or not a state suitable for load measurement can be obtained often depends on the route. For example, when quarrying is loaded above a mountain seen at a quarry site due to a cut-off of a natural mountain and going down a slope as it is, there is a problem that accurate load measurement cannot be performed because there is no flat place on the road. It was.

  An object of the present invention is to provide a load measuring device for a construction machine capable of measuring a load at a timing with little influence of a traveling state or a ground state and performing a load measurement with high accuracy.

(1) In order to achieve the above object, the present invention has pressure measuring means for measuring pressures of a body on which a load is loaded and a plurality of suspension cylinders that support the body of a construction machine, and is measured by the pressure detecting means. In the load measuring device for a construction machine that calculates the load of the load from the measured pressure value, based on the operation signal for operating the vehicle body and the speed signal for measuring the speed of the vehicle body, the vibration of the vehicle body and the friction of the cylinder A determination means for determining the working state of the construction machine that can reduce the influence of resistance is provided, and the load measurement value at the time when the vehicle body operation is stabilized is recorded.
With such a configuration, it is possible to measure the load at a timing that is less affected by the traveling state and the ground state, and perform accurate load measurement.

  (2) In the above (1), preferably, the working state of the construction machine is a state in which a load is loaded and moved, and a load measurement value during the movement is recorded. .

  (3) In the above (1), preferably, the state of the earthing is determined as a working state of the dump truck capable of reducing the influence of the shaking of the vehicle body and the frictional resistance of the cylinder, and during the reverse traveling performed at the time of earthing The load measurement value is recorded.

  According to the present invention, it is possible to measure the load at a timing with little influence of the traveling state and the ground state, and perform accurate load measurement.

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, etc. 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, and a load amount storage process S3, 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 of the load is calculated by subtracting the measured value of the empty load calculated from the cylinder pressure value in the unloaded state from the load measured value calculated from the cylinder pressure value in the loaded state.

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 FIGS.
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. 4 is an explanatory diagram of a route during dumping by a dump truck. FIG. 5 is a timing chart at the time of earthing by a dump truck. FIG. 5 (A) shows the gear of the transmission indicating the traveling direction of the vehicle body, FIG. 5 (B) shows the state of the body operation lever that determines whether the body is raised or lowered, and FIG. 5 (C) shows the vehicle body speed. FIG. 5D shows a load measurement value measured from the pressure of the suspension.

  In the work determination processing S2, the processing device 10 calculates the dump truck from the load value calculated in the load measurement processing, the vehicle body speed signal 5, the shift gear position signal 6, the state signal of the body operation lever 8 that is the body being lifted and lowered. Judgment of work is performed.

  Here, the work determination in the work determination process S2 and its transition will be described with reference to FIG. 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.

  Here, for convenience of explanation, it is assumed that the process starts from the empty load movement S21. 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. During loading, the processing device 10 always displays the current loading amount on the display device 20 mounted inside the cab or outside the vehicle.

  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. Here, the path | route at the time of earthing to the hopper 30 by the dump truck 1 is demonstrated using FIG.

  The dump truck 1 travels along the route (1), and the back surface is directed toward the hopper 30. Next, as shown in the route (2), the body 2 is brought close to the hopper 30 to release the earth. And it leaves | separates from the position of the hopper 30 by a path | route (3). These route patterns are the same as long as the dump truck's release location is not changed, and in particular, it is common that reverse travel is required on route (2).

  Therefore, the transition from the load movement S23 to the earth release S24 can be performed when the vehicle is moved backward.

  In FIG. 3, even after the transition to the state of earth release S24, if the vehicle advances forward more than a certain distance without earth release, the processing device 10 determines that it was not backward for earth release, and the load The state returns to the state of movement S23.

  In the state of the earthing S24, the processing device 10 performs a load log when the vehicle body is moving backward at a predetermined interval, and when the earthing is finished, the processing device 10 calculates the load load by analyzing the log. Do. It should be noted that the time required for reverse movement is shorter than that of normal load traveling, and even if the load measurement value during this time is recorded as time series data, the amount of use of the memory 16 of the control device can be reduced, so that time series data is saved. However, the load may be calculated by analyzing vibration and bias from the time-series data after releasing.

  Here, the load measurement at the time of earthing will be described with reference to FIGS. 4 and 5. Times t0 to t2 in FIG. 5 indicate various states during traveling on the route (1) in FIG. As shown in FIG. 5 (A), the transmission gear maintains the second speed. As shown in FIG. 5B, the body operation lever is not operated. Then, as shown in FIG. 5C, the vehicle body speed is decelerated, and at time t1, the vehicle body speed becomes zero because the route (1) is switched to the route (2).

  At time t2, as shown in FIG. 5A, when the transmission gear is in the reverse drive position, load measurement is started from time t2. Then, load measurement is continued at predetermined time intervals until time t3 when the reverse position is held.

  Thereafter, at time t3, as shown in FIG. 5 (A), the transmission gear is set to neutral (neutral), and then, as shown in FIG. 5 (B), the body operation lever is operated to wake up the body. Perform earthing. Assuming that earth release is completed at time t5, the body is lowered as shown in FIG. 5 (B) while moving forward with the transmission gear as the first speed as shown in FIG. 5 (A).

  Finally, in FIG. 3, when it is determined that the earthing has been completed, the state is changed from the earthing S24 to the empty load movement S21 again.

  The load amount storage process S3 stores the load measurement value calculated by the work determination process S2 in the RAM memory 16. As load measurement values, load measurement values at the completion of loading, load measurement values in an unloaded state, and load measurement values during reverse travel before earth release are stored. The start time and end time of a series of operations from unloading to unloading are simultaneously saved as a clock time stamp, and the distance and time of unloading and the distance and time of unloading are recorded in the same way. Is also good.

  As described above, in this embodiment, the state of the earthing S24, that is, the load log when the vehicle body is moving backward is performed at a predetermined interval, and the log is analyzed when the earthing is finished. Thus, the load capacity is calculated. Here, as an analysis of the log, for example, in the load measurement values shown in FIG. 5D, the average of the load measurement values from time t2 to t3 is obtained, and the empty load is calculated from the average value. Pull to determine the load capacity. In addition, as shown between times t2 and t3 in FIG. 5D, even in the reverse state, the load value to be measured may not be stable because the time immediately after time t2 is immediately after the start of reverse movement. Since the vehicle is decelerated by the brake for stopping just before time t3, the measured load value may not be stable, so except for the values immediately after time t2 and immediately before time t3. It is also possible to take an average value.

  The work of dump trucks operating at mines and quarry sites is 1) transporting by empty load to the loading site, 2) loading of earth and sand by the loader, and 3) loading of the loaded earth and sand to the discharge site. 4) It can be divided into 4 types: earth and sand release at a release place with a hopper. Here, the load load needs to be measured after the earth and sand are loaded and before the earth and sand are released. Moreover, since errors are likely to occur due to the influence of the static frictional resistance of the cylinder during stoppage, it is necessary to measure during running. Furthermore, the measurement accuracy is improved in a place where the road surface is not inclined, is flat, and the road surface is less uneven.

  Under such conditions, the earth of the truck has a structure in which earth and sand are released rearward, so that the body is usually lifted and released after being positioned on the hopper in reverse. Since the reverse speed is low, the body does not sway and fluctuations in the cylinder pressure of the suspension are small. Therefore, in the present embodiment, the loading load of the dump truck is calculated from the cylinder pressure during reverse travel in the earth. In addition, since the place where the earth is released is limited, the state of the traveling path of the dump truck is constant, and even if there is an influence caused by the inclination of the vehicle body, the correction is easy.

  In the above description, load measurement is performed by calculating the load when performing reverse travel during earth release. However, the present invention is not limited to backward travel during earth release, but the vehicle body shake and cylinder The load load may be calculated by measuring the load when the dump truck is in a working state in which the influence of the frictional resistance can be reduced. More specifically, such a working state of the dump truck is a state in which a load is loaded and moved, and a load measurement value is recorded while the load is being moved to obtain a load load. . As such a working state, it is possible to provide a predetermined measurement section not only when the earth is released but also when moving forward at the earthing place. In the example shown in FIG. 4, the route (2) is a route that moves backward at the time of earthing, but the route (1) is in a state of moving forward at the earthing location. The dumping place is suitable for stable measurement because the condition of the traveling path of the dump truck is constant. For example, in the route (1), a predetermined forward low speed constant speed traveling section is provided, and the traveling speed is below a predetermined speed. It may be determined that the vehicle is traveling forward for a predetermined time or more, the load is measured, and the load is calculated.

  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 may be read out by an external management device, and the load load may be calculated using the data of the empty load registered in advance.

  As described above, according to the present embodiment, it is possible to perform load measurement at the time of reverse travel before releasing the earth, in which it is desired to reduce the vibration of the vehicle body and the frictional resistance of the cylinder in the work of the dump truck. The accuracy of the value can be improved.

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 route explanatory drawing at the time of earthmoving by a dump truck. It is a timing chart at the time of earthmoving by a dump truck.

Explanation of symbols

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

Claims (3)

A pressure measuring means for measuring the pressure of a plurality of suspension cylinders for supporting a body for loading a load and a vehicle body of a construction machine;
In the load measuring device of the construction machine that calculates the load of the load from the pressure value measured by the pressure detecting means,
Based on an operation signal for operating the vehicle body and a speed signal for measuring the speed of the vehicle body, the determination means includes a determination unit that determines a working state of the construction machine that can reduce the influence of the vibration of the vehicle body and the frictional resistance of the cylinder,
A load measuring device for a construction machine, which records a load measurement value at a stable point of vehicle operation. In the load measuring device of the construction machine according to claim 1,
The working state of the construction machine is a state in which a load is loaded and moved, and a load measurement value is recorded while the load is being moved. In the load measuring device of the construction machine according to claim 1,
A construction characterized by determining a state of earthing as a working state of a dump truck capable of reducing the influence of the body vibration and the frictional resistance of the cylinder, and recording a load measurement value during reverse traveling performed at the time of earthing Machine load measuring device.

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