JP2005227270A - Method and apparatus for measuring loading weight of dump truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure loading weight of a dump truck in each operation state. <P>SOLUTION: The loading weight of a dump truck 11 is computed and stored at every prescribed time. It is determined whether the dump truck 11 has shifted into a transporting state or not (S31-S33). In the case that it has shifted into a transporting state (S31:YES, S32:YES, and S33:YES), a transporting weight G1 at the completion of loading immediately before the shift into a transporting state is computed and stored (S34). A transporting weight G2 during a period in the transporting state is also computed and stored (S35). In the case of the presence of a shift from a transporting state to an earth removal state (S36:YES), a transporting weight G3 before earth removal is computed and stored (S37). A selected transporting weight is read from among the transporting weights G1-G3 and outputted to a display device etc. (S38 and S39). It is thereby possible to measure the transporting weight at a plurality of previously set measuring timings. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dump truck load weight measuring method and a load weight apparatus.

Conventionally, a method of measuring the weight of a load by detecting the loads applied to the front and rear wheels of the dump truck and correcting each detected load based on the inclination angle of the vehicle body and the position of the center of gravity of the vehicle body. More known (Patent Document 1).
JP 61-34425 A

According to the prior art described in the above document, it is possible to determine the weight of the load only by detecting the loads applied to the front wheels and the rear wheels. However, in this prior art, the timing for measuring the load weight is not considered, and the measurement timing is fixed.
The dump truck is repeatedly used to transport loads such as earth and sand, for example, at a construction site or a mining site. The load loaded on the dump truck at the loading site is transported to a predetermined place by the dump truck and is lowered there. When the dump truck finishes unloading, it returns to the loading site and loads the load again.

The dump truck repeats such a work cycle. In order to grasp the progress of work and the operation efficiency of the dump truck, it is necessary to measure the weight (transport weight) of the load carried by the dump truck in each work cycle. Here, in this specification, when the weight of the load carried by the dump truck is distinguished from the load weight which is an instantaneous measurement value, it is referred to as a carry weight.
In order to properly grasp the progress of work, it is desirable to measure the transport weight under certain conditions every day. And at the time of the conveyance which the dump truck is drive | working, compared with other cases, a conveyance weight can be measured comparatively stably. Therefore, conventionally, the transport weight is measured only while the dump truck is traveling (transporting the load).

However, there is no guarantee that the state during transportation is always stable, and depending on the work site, it may be necessary to travel on a rough road with severe road surface irregularities. When traveling on such a rough road, the vehicle body shakes greatly, making it difficult to accurately measure the transported weight.
In particular, articulated dump trucks in which the front and rear vehicle bodies are connected in a refractive manner are often used in places with rough ground such as mines, and therefore, shaking during traveling is severe. Therefore, there are cases where the transported weight cannot be accurately measured during traveling.

  The present invention has been made paying attention to the above-mentioned problem, and one object thereof is a dump truck loading weight measuring method and a loading truck capable of measuring the loading weight in each of a plurality of preset work states. The object is to provide a weight measuring device. One of the objects of the present invention is to measure the load weight in each of a plurality of preset work states, and to output the load weight in the selected work state, and to measure the load weight of the dump truck and the load weight measurement. To provide an apparatus. One of the objects of the present invention is to provide a dump truck load weight measuring method and a load weight measuring apparatus capable of measuring each load weight in a plurality of work states at low cost. Further objects of the present invention will become clear from the description of the embodiments described later.

  In order to solve the above problems, a dump truck load weight measuring method according to the present invention includes a first step of detecting a plurality of work states of the dump truck, and a plurality of dump truck load weights for calculating the dump truck load weight. A second step for detecting basic information; and a second step for determining each loaded weight of the dump truck in a plurality of predetermined work states among the work states detected in the first step. A third step of calculating each based on the basic information detected in step 4, a fourth step of storing the calculated load weights, respectively, and outputting all or part of the stored load weights. And a fifth step.

The fifth step may be configured to output only the loaded weight in the selected predetermined work state among the loaded weights stored in the fourth step.
The predetermined plurality of work states include a specific work state among the respective work states detected in the first step, a state when shifting from a certain work state to the specific work state, and the specific The state at the time of shifting from one work state to another work state can be included.
For example, in the first step, it is possible to detect whether the dump truck is in an empty state, a loading state, a transporting state, or an unloading state. The third step includes a first loading weight when the dump truck is in a loading end state when the dump truck transitions from the loading state to the transportation state, and the dump truck is in the transportation state. The second loading weight and the third loading weight when the dump truck is in a state before discharging when the dump truck shifts from the transporting state to the discharging state. Each can be calculated based on the basic information.

In an embodiment of the present invention, the dump truck is supported by a pair of equalizer bars provided on the left and right sides of the vehicle body, respectively, and one side of each of the equalizer bars via a first suspension device. A first wheel, a second wheel supported on the other side of each equalizer bar via a second suspension device, a left wheel of the vehicle body spaced apart from each equalizer bar, and a third suspension respectively. And a third wheel supported via the device. The second step includes a second A step of detecting a first load applied to one of the first suspension device and the second suspension device as one of the basic information, and the third suspension device. 2B step of detecting the second load applied to the vehicle as one of the basic information, 2C step of detecting the tilt angle of the vehicle body as one of the basic information, and the second A and 2B2 steps. A second D step of calculating the loaded weight based on the first and second loads and the inclination angle detected by the second C step.
Further, the second D step is based on a ratio of distances from the rotation center of the equalizer bar to the first and second suspension devices and the first load detected in the first step. From the second D1 step for calculating the total load applied to each of the first and second suspension devices, the total load calculated in the second D1 step and the second load detected in the second step, A second D2 step for calculating a load in the vertical direction based on the inclination angle detected in three steps, a vertical component of the first load calculated in the second D2 step, and a vertical direction of the second load A second D3 step of calculating the loading weight by adding the components.

  A dump truck load weight measuring apparatus according to another aspect of the present invention includes a load weight calculating means for calculating a load weight of the dump truck, a work state detecting means for detecting each of a plurality of work states of the dump truck, and the load Storage means for storing each loaded weight when a plurality of predetermined work states are detected by the work state detection means among the plurality of load weights respectively calculated by the weight calculation means, and each of the predetermined plurality of load weights Output selection means for reading out the loaded weight in the selected predetermined work state from the storage means from the storage means and outputting it can be provided.

According to the present invention, the weight of the load loaded on the dump truck can be measured in each of a plurality of work states. By measuring the load weight in each work state, the operation status of the dump truck, the progress status of the work, etc. can be considered from various aspects, and the usability is improved.
According to the present invention, it is possible to select which of the loaded weights measured in each work state is to be adopted according to the work environment of the dump truck. Thereby, an appropriate timing can be selected according to the work environment of the dump truck, and the loaded weight can be measured more accurately.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, as described below, the vehicle body (24, 25), the vessel (21) provided on the vehicle body (25), and the left and right sides of the vehicle body (25) are provided so as to be rotatable. A pair of equalizer bars (30), a first wheel (18) supported on one side of each of the equalizer bars (30) via a first suspension device (31), and other equalizer bars (30) A second wheel (19) supported on each side via a second suspension device (16), and provided on the left and right sides of the vehicle body (24) apart from each equalizer bar (30). A dump truck (11) comprising a third wheel (17) supported via (14) is disclosed.

  The dump truck (11) includes first load detection means (23, 230) for detecting a first load applied to one of the first suspension device (31) and the second suspension device (16). The second load detecting means (22, 220) for detecting the second load applied to the third suspension device (14), the tilt angle detecting means (20) for detecting the tilt angle of the vehicle body (25), and the first Based on the second load and the inclination angle, the control means (47) for calculating the load weight of the vessel (21) and the output means (48, 47B) for outputting the load weight calculated by the control means (47). 114).

  Although details will be described later, in the present embodiment, a plurality of work states of the dump truck (11) are respectively detected, and whether or not a predetermined work state set in advance is reached is monitored. In this embodiment, when a predetermined work state is detected, the loaded weight in the work state is stored in a storage unit such as a memory. The storage means stores measurement values in a plurality of predetermined work states. A dump truck manager or the like can select a measurement value to be employed according to the working environment of the dump truck (11).

First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view of an articulated dump truck 11.
As shown in FIG. 1, the dump truck 11 includes a front vehicle body 24 located on the front side and a rear vehicle body 25 located on the rear side. The front vehicle body 24 is supported by a front frame 27, and the rear vehicle body 25 is supported by a rear frame 28. The rear frame 28 is coupled to the front frame 27 so as to be able to bend and swing. A cab 36 is mounted on the front frame 27.

  A pair of left and right steering cylinders 35, 35 are bridged between the front frame 27 and the rear frame 28. By expanding and contracting each of the steering cylinders 35 and 35, the rear frame 28 can be refracted with respect to the front frame 27, and the steering operation can be performed.

  Above the rear frame 28, for example, a vessel 21 for loading a load such as earth and sand is provided. A pair of lift cylinders 26, 26 are provided between the left and right sides of the front portion of the vessel 21 and the rear frame 28. The rear lower side of the vessel 21 is attached to the rear frame 28 by a vessel pin 37 so as to be rotatable. As the lift cylinders 26 and 26 expand and contract, the vessel 21 rotates in the vertical direction around the vessel pin 37. The operation of raising the vessel 21 is called dumping up, and the operation of lowering the vessel 21 is called dumping down. FIG. 1 shows a state where the vessel 21 is fully lowered and seated on the rear frame 28.

The front frame 27 is provided with a V-shaped front arm 12 so as to be rotatable in a plan view. The front end 12A (V-shaped apex side) of the front arm 12 is supported by the lower part of the front arm 27 so as to be rotatable in the vertical direction.
A pair of left and right front wheels 17, 17 are attached to both side surfaces of the rear end portion 12B of the front arm 12. Each of these front wheels corresponds to an example of a “third wheel”. The upper portion of the rear end portion 12B is supported by the front frame 27 via the front suspension cylinder 14 which is an example of a “third suspension device”.

Here, FIG. 2 is a plan view of the rear frame 28 shown with the vessel 21 and the like removed. As shown in FIGS. 1 and 2, a pair of left and right equalizer bars 30, 30 are rotatably provided on both side surfaces of the rear frame 28. The substantially central portions of the equalizer bars 30 and 30 are rotatably attached to the rear frame 28 by pins 29 and 29.
A center arm 13 and a rear arm 15 are rotatably provided at the lower portion of the rear frame 28. As with the front arm 12, the center arm 13 and the rear arm 15 are each formed in a V shape in plan view.

  The front end portion 13A of the center arm 13 is supported on the lower front side of the rear frame 28 so as to be rotatable in the vertical direction. A pair of left and right middle wheels 18, 18 are attached to both side surfaces of the rear end portion 13 </ b> B of the center arm 13. Each of the middle wheels 18 and 18 corresponds to an example of a “first wheel”. The upper portion of the rear end portion 13B is supported on the lower side of the front end portions of the equalizer bars 30 and 30 via springs 31 and 31 which are examples of the “first suspension device”.

  The front end 15A of the rear arm 15 is supported on the lower rear side of the rear frame 28 so as to be rotatable in the vertical direction. A pair of left and right rear wheels 19, 19 are attached to both side surfaces of the rear end portion 15B of the rear arm 15. Each of the rear wheels 19 and 19 corresponds to an example of a “second wheel”. The upper portion of the rear end portion 15B is supported on the lower side of the rear end portion of the equalizer bar 30 via a rear suspension cylinder 16 which is an example of a “second suspension device”.

  FIG. 3 is a side view showing the equalizer bar 30 partially enlarged. As shown in FIG. 3, stoppers 51, 51 are provided on both side surfaces of the rear frame 28 so as to correspond to the front end portion and the rear end portion of the equalizer bar 30, respectively. The stoppers 51 and 51 are provided so as to slightly protrude from the side surface of the rear frame 28 toward the equalizer bar 30.

  Bases 52 and 52 are provided on the side surfaces of the equalizer bar 30 so as to correspond to the stoppers 51 and 51, respectively. The bases 52 and 52 are provided so as to slightly protrude toward the equalizer bar 30 side. When the equalizer bar 30 tries to rotate more than a predetermined angle, the bases 52 and 52 come into contact with the stoppers 51 and 51, so that further rotation is restricted.

Returning to FIG. A controller 47 for measuring the loaded weight is installed in the cab 36 of the dump truck 11. The controller 47 is an example of “control means”.
An external display lamp set 48 is provided on the roof of the cab 36. The external display lamp set 48 is for displaying the ratio of the load weight to the rated load weight to the outside. The external display lamp set 48 can be configured to include, for example, a plurality of lamps 48A, 48B, and 48C having different lighting colors. For example, the lamp 48A is lit green, the lamp 48B is orange, and the lamp 48C is red.

  The controller 47 controls lighting and extinguishing of the lamps 48 </ b> A to 48 </ b> C according to the weight of the load loaded on the vessel 21. For example, when the loaded weight is 50% or less of the rated loaded weight, the controller 47 does not light any lamp. When the loaded weight is 50 to 89% of the rated loaded weight, the controller 47 turns on the green lamp 48A. When the loaded weight is 90 to 100% of the rated loaded weight, the controller 47 turns on the orange lamp 48B. When the loaded weight is 100% or more of the rated loaded weight, the controller 47 turns on the red lamp 48C.

  In consideration of the measurement error of the load weight, when the load weight is within 90 to 104% of the rated load weight, the orange lamp 48B is turned on. Similarly, the load weight is 105% or more of the rated load weight. In this case, the red lamp 48C may be turned on. The lamp lighting color and the load weight rank (50% or less, 50 to 89%, 90 to 100%, 100% or more) are merely examples, and various modifications can be made.

  The loading operator who loads the load on the vessel 21 of the dump truck 11 performs the loading operation while looking at the display on the external display lamp set 48. The loading operator loads the load on the vessel 21 so that the loaded weight is about 100% of the rated loaded weight.

  The rear frame 28 is provided with an inclination sensor 20 which is an example of “inclination angle detection means”. The inclination sensor 20 measures the inclination of the vehicle body in the front-rear direction and outputs a detection signal to the controller 47.

  A seating sensor 46 is provided between the rear frame 28 and the vessel 21. The seating sensor 46 is for determining whether or not the vessel 21 is seated on the rear frame 28. When the vessel 46 is seated on the rear frame 28, the seating sensor 46 detects this seating state and outputs it to the controller 47.

  A vehicle speed sensor 49 is provided on the output shaft of the transmission (not shown). The vehicle speed sensor 49 detects the rotation speed (vehicle speed) of the output shaft and outputs it to the controller 47.

The front suspension cylinder 14 is provided with a front pressure sensor 22 as an example of “second load detecting means”. The front pressure sensor 22 detects the oil pressure in the front suspension cylinder 14 and outputs it to the controller 47.
Similarly, the rear suspension cylinder 16 is provided with a rear pressure sensor 23 as an example of “first load detection means”. The rear pressure sensor 23 detects the pressure of oil in the rear suspension cylinder 16 and outputs it to the controller 47.

  The pressure sensors 22 and 23, the inclination sensor 20, the seating sensor 46, and the vehicle speed sensor 49 are electrically connected to the controller 47, respectively. As will be described later, the controller 47 can receive signals from these sensors.

FIG. 4 shows a cross-sectional view of the suspension cylinder. Here, the front suspension cylinder 14 will be described as an example, but the rear suspension cylinder 16 has substantially the same configuration.
As shown in FIG. 4, the front suspension cylinder 14 includes a piston 38 and a cylinder 39 to which the piston 38 is slidably attached. The piston 38 is composed of, for example, a bottomed cylindrical piston main body 38A and a cylindrical ring member 38B provided on the upper outer peripheral side of the piston main body 38A.
Oil 40 is sealed in the piston main body 38A. A nitrogen gas 41 is sealed in the space between the piston 38 and the cylinder 39.

  Between the piston body 38A and the cylinder 39, an annular cavity 42 is provided below the ring member 38B. The piston main body 38A is provided with a predetermined number of first orifices 43 spaced apart in the circumferential direction at predetermined positions in the longitudinal direction. Each first orifice 43 is formed so as to communicate the internal space of the piston main body 38 </ b> A and the cavity 42. In addition, a predetermined number of second orifices 44 are provided at positions different from the first orifice 43 in the longitudinal direction and spaced apart in the circumferential direction. A check ball 45 is provided outside each of the second orifices 44.

  For example, when the front wheel 17 rides on a projection or the like on the road surface, the piston 38 moves upward and enters the cylinder 39 because the front wheel 17 is lifted by the projection. That is, the front suspension cylinder 14 contracts. As a result, when the piston 38 enters the cylinder 39, the volume of the space defined between the upper portion of the piston 38 and the cylinder 39 decreases, so that the nitrogen gas 41 is compressed. As the front suspension cylinder 14 is reduced, the pressure of the oil 40 enclosed in the piston main body 38A also increases. Thereby, the oil 40 in the piston main body 38 </ b> A flows into the cavity 42 through the first orifices 43 and the second orifices 44, respectively.

  On the other hand, when the front wheel 17 gets over the protrusion, the piston 38 moves downward and the front suspension cylinder 14 extends. As the piston 38 moves backward in the cylinder 39, the pressure in the piston main body 38A decreases. Since each second orifice 44 is blocked by the check ball 45, the oil 40 in the cavity 42 passes only through each first orifice 43 and returns to the piston body 38A.

  On the upper side of the cylinder 39, a pressure measurement hole 39A for measuring the pressure of the nitrogen gas 41 is formed. One end side of the pressure measurement hole 39 </ b> A communicates with the space between the cylinder 39 and the piston 38, and the other end side opens from above the cylinder 39 to the outside. A front pressure sensor 22 is provided on the other end side of the pressure measurement hole 39A.

  The pressure of nitrogen 41 sealed between the cylinder 39 and the piston 38 is guided to the front pressure sensor 22 through the pressure measurement hole 39A. The front pressure sensor 22 converts the pressure of the nitrogen gas 41 into an electrical signal and outputs it to the controller 47. By measuring the pressure of the nitrogen gas 41, the load applied to the front suspension cylinder 14 (corresponding to the example of “second load”) can be measured. Thereby, it is possible to obtain the load applied to the front wheel 17 to which the front suspension cylinder 14 is attached.

  FIG. 5 is a block diagram showing a schematic configuration of the controller 47. The controller 47 corresponds to an example of a “dump truck load weight measuring device”. The controller 47 can be configured as a microcomputer system.

  The controller 47 includes, for example, a CPU (Central Processing Unit) 110, a ROM (Read Only Memory) 111, a RAM (Random Access Memory) 112, a display driving circuit 113, a communication interface 114, an input interface 115, and an output. An interface 116 and a bus 117 for connecting these units to each other can be provided.

  CPU 110 reads and executes the microcode stored in ROM 111. Thereby, each process mentioned later is performed. The RAM 112 is used as a work area for temporarily storing results during the calculation. The RAM 112 can also store control flag information and the like.

  The display drive circuit 113 drives a display device 47C provided in the cab 36. This display device 47C can appropriately display information on the loaded weight. The communication interface 114 can be provided, for example, when data communication is performed with a management server (not shown) installed in a management center or the like. If the display device 47C is not used, the display drive circuit 113 is not necessary. Further, when the controller 47 does not perform data communication or the like with an external device, the communication interface 114 is unnecessary.

  The input interface 115 is a circuit for receiving signals from various sensors. For example, a manual switch 47A, a seating sensor 46, a vehicle speed sensor 49, a tilt sensor 20, a front pressure sensor 22, and a rear pressure sensor 23 can be connected to the input interface 115, respectively. The manual switch 47A is, for example, a switch for instructing the controller 47 to start calibration processing, turn on the power, etc., and can be provided in the cab 36. The manual switch 47A is operated by the operator of the dump truck 11.

  The output interface 116 is a circuit for outputting a control signal from the controller 47 to the outside. For example, an external display lamp set 48 or a printer 47B as an example of an external output device can be connected to the output interface 116. The external output device is not limited to the printer 47B, and may be various storage devices such as a flexible disk device, an optical disk device, a hard disk device, and a semiconductor memory device. By recording the loaded weight measured by the controller 47 on a recording medium together with the measurement date and time, the operation rate of the dump truck 11 can be analyzed.

  The configuration shown in FIG. 5 is an example, and the present invention is not limited to this. For example, the controller 47 can be configured as a hardware circuit from a logic LSI (Large Scale Integration) or the like.

  FIG. 6 is a block diagram that focuses on the functional configuration of the controller 47. The controller 47 can include, for example, a calculation unit 210, a front side load detection unit 220, a rear side load detection unit 230, a work state detection unit 240, a storage unit 250, and an output selection unit 260. First, after describing the peripheral functions of the calculation unit 210, details of the calculation unit 210 will be described.

  The front side load detection unit 220 detects a load (“second load”) applied to the front suspension cylinder 14 based on a detection signal from the front pressure sensor 22. Similarly, the rear load detection unit 230 detects a load (“first load”) applied to the rear suspension cylinder 16 based on a detection signal from the rear pressure sensor 23. Each of these load detection units 220 and 230 can be realized by the CPU 110 reading and executing the microcode stored in the ROM 111, for example. The load detection units 220 and 230 do not need to be provided in the controller 47, and may be provided in the pressure sensors 22 and 23. That is, each of the pressure sensors 22 and 23 can be configured as an intelligent pressure sensor including a signal processing LSI or the like.

The work state detection unit 240 is an example of a “work state detection unit”. For example, as described in conjunction with FIG. 10, the work state detection unit 240 detects each work state (an empty state, a loading state, a traveling state, and a soil removal state) of the dump truck 11.
The work state detection unit 240 is a state when shifting from the respective work state to the running state (loading end state) and a state when shifting from the running state to another work state (before the earth is dumped). State).
For example, signals from a manual switch 47A, a seating sensor 46, and a vehicle speed sensor 49 are input to the work state detection unit 240, respectively. The work state detection unit 240 also receives the loaded weight calculated by the calculation unit 210. The work state detection unit 240 detects each work state of the dump truck 11 based on these signals and the loaded weight. The work state detection unit 240 can be realized, for example, when the CPU 110 reads and executes the microcode stored in the ROM 111.

The storage unit 250 is an example of a “storage unit”, and can be realized by the RAM 112, for example. The storage unit 250 can store, for example, a load weight calculated by the calculation unit 210, an initial load in an empty state, control information, signal values from each sensor, and the like.
In addition, the storage unit 250 stores each loaded weight in a plurality of predetermined work states detected by the work state detection unit 240 among the plurality of load weights calculated by the calculation unit 210. For example, the storage unit 250 stores a transport weight G1 at the end of loading, a transport weight G2 during travel, and a transport weight G3 before discharging.
These transport weights G1 to G3 are stored for each work cycle. That is, the storage unit 250 stores, for example, storage date / time (measurement date / time), information for identifying the work state, and transported weight in association with each other.

The output selection unit 260 is an example of an “output selection unit”. For example, the storage unit 250 and the manual switch 47A are input to the input side of the output selection unit 260, respectively. For example, an external display lamp set 48, a printer 47B, and a display device 47C are connected to the output side of the output selection unit 260, respectively.
For example, based on the selection signal input from the manual switch 47A, the output selection unit 260 selects the transport weight in the selected work state among the transport weights G1 to G3 in each work state stored in the storage unit 250. It is to be output to the outside. The output selection unit 260 can be realized, for example, when the CPU 110 reads and executes the microcode stored in the ROM 111.
Various methods can be adopted as a method for selecting the carrying weight. For example, the traveling weight G2 during traveling is selected as an initial value in advance from G1 to G3 of each traveling weight, and in the normal case, the traveling weight G2 is read from the storage unit 250 and output to the outside. When an explicit switching instruction is input, the other transport weights G1 and G3 can be read from the storage unit 250 and output to the outside instead of the travel weight G2.
Or the output selection part 260 can also read each conveyance weight G1-G3 in order from the memory | storage part 250 in a predetermined order (for example, progress order of a work cycle), and can also output each outside.
An instruction as to which of the transport weights G1 to G3 is to be output can be given from the manual switch 47A to the controller 47, or from the management device or the like existing outside the dump truck 11 to the controller 47. Can also be given.

The calculation unit 210 performs calculation processing. The calculation unit 210 can include, for example, a front load vertical direction component calculation unit 211, a total load vertical direction calculation unit 212, a total load calculation unit 213, and a total load calculation unit 214.
Note that these units 211 to 214 are realized, for example, by the CPU 110 reading and executing microcode. That is, each of the units 211 to 214 is a function and does not mean a physical circuit configuration. However, at least one of each of the units 211 to 214 can be configured as a physical circuit.

  The front load vertical component calculation unit 211 calculates the vertical component of the front load based on the front load detected by the front load detector 220 and the vehicle body inclination angle detected by the inclination sensor 20. calculate.

  The total load calculation unit 213 calculates the total load applied to the spring 31 and the rear suspension cylinder 16 based on the rear side load detected by the rear side load detection unit 230 and the mechanical setting values of the equalizer bar 30 and the like. . That is, the total value of the loads applied to the middle wheel 18 and the rear wheel 19 is calculated.

  As will be described later, when the middle wheel 18 and the rear wheel 19 are balanced by the equalizer bar 30 as shown in FIG. 3, the moment on the middle wheel 18 (center moment) and the moment on the rear wheel 19 (rear) Is equal to (moment). The center moment is obtained as a product (F1 · D1) of the center load F1 and the distance D1 from the pin 29 to the center of the spring 31. The rear moment is obtained as a product (F2 · D2) of the rear load F2 and the distance D2 from the pin 29 to the center of the rear suspension cylinder 16.

  Therefore, F1 = (F2 · D2) / D1 can be obtained from (F1 · D1) = (F2 · D2). As shown by this equation, the center load F1 can be obtained only from the rear load F2 and the mechanical setting values (D1, D2) of the equalizer bar 30. By performing such calculation, the total load calculation unit 213 can calculate the total value of the loads applied to the center side and the rear side.

  The total load vertical direction component calculation unit 212 calculates the vertical component of the total load based on the total load detected by the total load detection unit 213 and the vehicle body inclination angle detected by the inclination sensor 20.

  The total load calculation unit 214 adds the calculation result of the front load vertical direction component calculation unit 211 and the calculation result of the total load vertical direction component calculation unit 212 to calculate the total load. The total load calculated in the empty state is the initial load. If the initial load is subtracted from the total load calculated in the loaded state, the current loaded weight can be obtained.

  Then, lighting of the external display lamp set 48 is controlled based on the rank of the loaded weight calculated by the total load calculation unit 214. The calculated load weight is stored in the storage unit 250 or printed on the printer 47B. Furthermore, for example, information such as the calculated loading weight, measurement date and time, and identification information of the dump truck 11 can be transmitted to an external management device via the communication interface 114.

  Hereinafter, the procedure for measuring the loaded weight will be described. When detecting the loaded weight, first, all loads applied to the front wheel 17, the middle wheel 18 and the rear wheel 19 are measured in an empty state in which no load is loaded on the vessel 21. That is, the initial load before loading is measured. This measurement of the initial load is referred to as calibration in this specification. The initial load when the vessel 21 is empty is the sprung weight of the dump truck 11 in the empty state. The initial load can also be called, for example, “empty load”. After measuring the initial load, the total load when the load is loaded on the vessel 21 is measured, and the initial load is subtracted from the total load to calculate the load weight of the load.

  FIG. 7 is a flowchart showing an outline of the calibration process. In the following description, the suspension cylinder and pressure sensor on one side among the suspension cylinders and pressure sensors respectively provided on the left and right sides of the vehicle body will be described, but in practice, the same calculation is performed on the other side. And take the average of the values obtained on both sides. “Step” is abbreviated as “S”.

  When executing the calibration process, the dump truck 11 is made to travel straight on a relatively flat ground at a predetermined substantially constant speed for a predetermined time t1 (for example, 30 seconds) or more with the vessel 21 empty. This is called calibration running. Therefore, in this process, first, it is determined whether or not calibration running has been started (S10). Whether or not the calibration travel has started can be determined based on signals from the vehicle speed sensor 49 and the seating sensor 46, for example.

When the calibration running is started (S10: YES), the controller 47 starts a timer for measuring the predetermined time t1 (S11).
Further, the controller 47 detects a load applied to the front suspension cylinder 14 based on a signal from the front pressure sensor 22 provided in the front suspension cylinder 14 (S12). The load applied to the front suspension cylinder 14 detected in S12 is referred to as a front side load.

Next, the controller 47 detects a load (hereinafter referred to as a rear load) applied to the rear suspension cylinder 16 based on a signal from the rear pressure sensor 23 provided in the rear suspension cylinder 16 (S13).
The controller 47 doubles the detected rear load (S14). Thereby, the sum of the rear load and the load applied to the spring 31 (hereinafter referred to as the center load) is obtained. This is the total load.

  Here, S14 will be described in detail. As shown in FIG. 3, the middle wheel 18 and the rear wheel 19 are supported on both ends of a rotatable equalizer bar 30 via a spring 31 and a rear suspension cylinder 16. When the rotatable equalizer bar 30 is not rotating, the moment applied to the front end portion of the equalizer bar 30 is equal to the moment applied to the rear end portion of the equalizer bar 30.

  That is, as described above, the product (F1 · D1) of the center load F1 and the distance D1 from the pin 29 to the center of the spring 31 is the distance from the rear load F2 to the center of the rear suspension cylinder 16 from the pin 29. It is equal to the product (F2 · D2) with D2. Therefore, as described above, F1 = (F2 · D2) / D1 can be obtained. From this equation, it can be seen that the center side load F1 can be obtained by multiplying the rear side load F2 by (1 + D2 / D1) (F1 = F2 × (1 + D2 / D1)).

  In the present embodiment, a pin 29 is provided at a substantially central portion of the equalizer bar 30, and the values of D1 and D2 are substantially matched (D1 = D2). Since the distance from the pin 29 serving as a fulcrum becomes equal, the rear load F2 and the center load F1 are substantially equal (F1 = F2). Therefore, the total load (F1 + F2) can be obtained only by doubling the rear load F2.

  Next, the controller 47 detects the tilt angle in the front-rear direction of the dump truck 11 based on the signal from the tilt sensor 20 (S15). Based on the inclination angle, the controller 47 corrects the front side load and the total load of the center load and the rear load to loads that are respective vertical components (S16). Thereby, the correction value of the front side load applied to the front wheel 17 and the correction value of the total load applied to the middle wheel 18 and the rear wheel 19 are respectively obtained.

The controller 47 adds the correction value of the front load and the correction value of the total load to calculate a total value (S17). The controller 47 stores the grand total value in the storage unit 250 and repeats S12 to S17 until the predetermined time t1 elapses (S18).
When the predetermined time has elapsed (S18: YES), the controller 47 obtains an average value of a plurality of grand total values stored in the storage unit 250 (S19). This average value is the initial load of the dump truck 11. The controller 47 stores the calculated initial load in the storage unit 250 and ends this process.

FIG. 8 is a flowchart showing an outline of a process for measuring a load weight when a load is loaded on the vessel 21. This process can be performed in a procedure substantially similar to the procedure shown in S10 to S19 in FIG.
First, the controller 47 determines whether or not to start the processing for measuring the loaded weight (S10A). For example, if the manual switch 47A includes a “measurement start switch”, the operator operates this switch to start the load weight measurement process (S10A: YES).

  Here, for example, when the start date and time of the load weight measurement process is compared with the registration date and time of the initial load stored in the storage unit 250, when a predetermined period or more has elapsed from the registration date and time of the initial load, It is also possible to prompt the operator to re-register the initial load via the external display lamp set 48 or the display device 47C. Alternatively, when the measurement result of the load weight measurement process is output, the value of the initial load that is the basis of the calculation and the registration date and time may be output together.

When the measurement process is started, the controller 47 starts a timer for measuring the second predetermined time t2 (S11A). This timer t2 is used for measuring the load weight a plurality of times.
As described in the calibration process, the controller 47 detects the front side load and the rear side load (S12A, S13A), and doubles the rear load to obtain the total load (S14A). Subsequently, the controller 47 detects the tilt angle (S15A), and corrects the front side load and the total load based on the tilt angle (S16A).

The controller 47 adds the vertical component of the front side load and the vertical component of the total load to calculate the total load (S17A). The controller 47 stores the calculated total load in the storage unit 250, and repeats S12A to S17A until a predetermined time t2 has elapsed (S18A).
When the predetermined time t2 has elapsed (S18A: YES), the controller 47 calculates the average of a plurality of total loads stored in the storage unit 250, and subtracts the initial load from the average value to calculate the loaded weight ( S19A).

As described above, according to the present embodiment, the middle wheel 18 and the equalizer bar 30 are supported by the spring 31, and the rear wheel 19 and the equalizer bar 30 are supported by the front suspension cylinder 14.
Then, a rear load is obtained by a rear pressure sensor 23 provided in the rear suspension cylinder 16, and this is doubled to obtain a total load of the center load and the rear load. In this embodiment, it is sufficient to directly detect only the rear side load, and it is not necessary to directly detect the load applied to the spring 31 supporting the middle wheel 18. Therefore, there is no need to provide a sensor for detecting the amount of expansion / contraction of the spring 31.
Further, in this embodiment, it is not necessary to replace the spring 31 with a suspension cylinder in order to support the middle wheel 18 or to provide a pressure sensor in order to obtain a load applied to the suspension cylinder.
Thus, in this embodiment, the load weight can be accurately measured with a small number of sensors, and the load weight measurement performance of the dump truck 11 can be improved without significantly increasing the manufacturing cost.

  Note that it is also conceivable that the oil 40 in the suspension cylinders 14 and 16 decreases due to aging, and the outputs of the pressure sensors 22 and 23 fluctuate. In order to calibrate this, it is desirable to perform calibration periodically to measure the initial load.

  Next, a method of measuring the loaded weight for each of a plurality of predetermined work states will be described with reference to FIGS. In the present embodiment, the load weight is calculated for each work state included in one work cycle of the dump truck 11, and the load weight (transported weight) in a predetermined work state is stored.

  First, a general work procedure of the dump truck 11 will be described. FIG. 9 shows the work procedure of the dump truck 11. The dump truck 11 has an empty vessel 21 seated on the rear frame 28 and is stopped at the loading site (S21). The loading operator loads a load such as earth and sand on the vessel 21 using a hydraulic excavator, a wheel loader, or the like (S22).

When the loaded weight G is equal to or greater than the predetermined value GM (S23: YES), the dump truck 11 starts traveling and transports the loaded material to a predetermined dump site (S24). The dump truck 11 arriving at the dumping site dumps up the vessel 21 and dumps the load (S25).
After dumping is completed, the dump truck 11 dumps the empty vessel 21 and returns to the loading field to resume loading (S26).
The dump truck 11 sets S21 to S25 as one work cycle and repeats the work cycle a plurality of times.

  Next, a method for measuring and outputting the transported weight of the load transported by the dump truck 11 from the loading site to the dumping site at a desired timing will be described. In the following description, it is assumed that calibration has already been completed.

The controller 47 detects the vehicle speed V from the signal from the vehicle speed sensor 49 and determines whether or not the vessel 21 is seated from the signal from the seating sensor 46. Further, the controller 47 calculates the loaded weight based on the signals from the pressure sensors 22 and 23 and the tilt sensor 20 (S10A to S19A).
The controller 47 causes the storage unit 250 to store the values of the signals output by the sensors 20, 22, 23, 46, and 49 together with the loaded weights detected at the respective measurement timings.

Hereinafter, it demonstrates in detail along the work cycle (S21-S25) mentioned above. FIG. 10 is a timing chart showing how the vehicle speed V, the seating state of the vessel 21, and the loaded weight G change in one work cycle.
The upper part of FIG. 10 shows how the vehicle speed V of the dump truck 11 changes during the progress of the work cycle. The vertical axis represents the vehicle speed V, and the horizontal axis represents the passage of time.
The middle stage in FIG. 10 shows how the seating state (sitting or non-sitting) of the vessel 21 changes during the progress of the work cycle. The vertical axis represents the state of the vessel 21, and the horizontal axis represents the passage of time.
The lower part of FIG. 10 shows how the loading weight G of the dump truck 11 changes during the progress of the work cycle. The vertical axis represents the loading weight G, and the horizontal axis represents the passage of time.

At a certain time t0, the dump truck 11 is stopped at the loading place, and nothing is loaded on the vessel 21. That is, at time t0, the empty dump truck 11 is stopped at the loading place.
At time t1, loading of the load on the vessel 21 is started by a work machine such as an excavator or a wheel loader. As the loading operation progresses, the loading weight G increases step by step. Eventually, at time t2, the load weight G of the vessel 21 reaches a predetermined weight threshold Gth set in advance. This threshold Gth can be set to about half of the rated load weight, for example.

The period (t0-t2) until the loaded weight G reaches the threshold value Gth is an empty state. When the loaded weight G reaches the threshold value Gth, the loading state is entered.
The loading operation is continued even after the loaded weight G exceeds the threshold value Gth. At time t3, the loaded weight G reaches a predetermined upper limit value GM. This upper limit value GM can be set to about 100% of the rated load weight, for example.

When the loaded weight G reaches the upper limit value GM, the dump truck 11 starts traveling. Thereby, conveyance of a load is started (t4). That is, the dump truck 11 starts to shift from the loading state to the transporting state.
As the vehicle travels, the vehicle speed V increases, and exceeds the travel detection threshold VL at time t5. This completes the transition from the loading state to the carrying state. Further, at time t6, the vehicle speed V exceeds the threshold value VH for average detection (VH> VL), and continues to increase thereafter, eventually reaching a substantially constant value.

As the dump truck 11 approaches, the dump truck 11 gradually decreases the vehicle speed V. At time t7, the vehicle speed V falls below the average detection threshold value VH, and at time t8, the dump truck 11 stops at the dump site.
The dump truck 11 stopped at the dumping site extends the lift cylinder 26 at time t9. Thereby, the vessel 21 is dumped up, and the load is lowered from the vessel 21 to the outside (soil removal). The loading weight G decreases by the start of the earth removal work. When the vessel 21 dumps up, the vessel 21 moves away from the rear frame 28 and changes from the seated state to the non-seat state. At time t9, the dump truck 11 shifts from the carrying state to the soil removal state.
When the unloading is completed, the dump truck 11 dumps down the vessel 21 and returns to the loading site. When the vessel 21 is dumped down, the vessel 21 is seated again on the rear frame 28 and returns from the non-sitting state to the sitting state. The dump truck 11 arrives at the loading place at time t10, and a new loading operation is started (t11).

  In such a work cycle (time t0 to t10), from time t0 to time t2 when the loaded weight exceeds the weight threshold Gth is referred to as an empty state in this specification. Similarly, a period from time t2 to time t5 when the dump truck 11 exceeds a predetermined travel detection threshold VL is referred to as a loading state. The period from time t5 to time t9 when the dump truck 11 starts discharging is referred to as a transporting state. A period from time t9 to time t10 when the dump truck 11 returns to the loading place and stops is called a soil removal state.

  During the work cycle, the controller 47 calculates the loaded weight at that time and displays it on the display device 47C in real time, and calculates the transport weight at each of the following measurement timings by calculation. The controller 47 stores the transport weight calculated at each measurement timing in the storage unit 250 together with information such as the measurement date and time.

Examples of the measurement timing include completion of loading (immediately before the start of transportation), transportation, and before soil removal (after completion of transportation).
The transporting weight G1 at the end of loading is a loading weight immediately before the dump truck 11 loaded with a load starts transporting at time t5.
The transporting weight G2 during the traveling of the vehicle is an average value of the loading weight during the period (t6 to t7) in which the dump truck 11 transports the load to the dump site.
The transport weight G3 immediately before dumping is the loaded weight immediately before the dump truck 11 arrives at the dumping site, dumps up the vessel 21 at time t9, and performs dumping.

  Then, the controller 47 can output to the outside together with information on which type of transport weight the at least one of the three types of transport weights G1, G2, G3 belongs.

For example, the controller 47 can output all of the three types of transport weights G1, G2, and G3, or the controller 47 can select any one selected by the manual switch 47A after the end of the work cycle. Only one or a plurality of transport weights can be output to the outside.
In addition, it may be configured such that which type of transport weight is output first and only the transport weight is output. The transported weight that has not been output may be stored in the storage unit 250 so that it can be output later, or may be immediately deleted.

FIG. 11 is a flowchart showing a process for measuring and outputting the transport weight in each work state of the work cycle.
When the work cycle is started, the controller 47 confirms that the dump truck 11 is in an empty state (S31).
For example, based on each signal from each sensor 20, 22, 23, 46, 49, the controller can determine that it is in an empty state when all of the following two conditions are satisfied. That is, if the first condition that the vessel 21 is seated and the second condition that the loaded weight G is less than the threshold value Gth are satisfied, the controller 47 indicates that the dump truck 11 is in an empty state. Can be determined. These two conditions can be called, for example, “predetermined empty state detection conditions”.

When it is determined that the dump truck 11 is in an empty state (S31: YES), the controller 47 waits until the dump truck 11 shifts to a loading state (S32).
For example, when the controller 47 satisfies all of the following three conditions based on the signals from the sensors 20, 22, 23, 46, and 49, the dump truck 11 shifts from an empty state to a loading state. Can be determined. That is, the first is that the vessel 21 is seated, the second is that the loaded weight G is greater than or equal to the threshold Gth, and the third is that the vehicle speed V is less than the threshold VL for detecting travel. This is the case when the condition is satisfied. These three conditions can be called, for example, “predetermined loading state detection conditions”.

When the transition to the loading state is detected (S32: YES), the controller 47 waits until the state shifts from the loading state to the transporting state (S33).
For example, when the controller 47 satisfies all of the following three conditions based on signals from the sensors 20, 22, 23, 46, and 49, the dump truck 11 has shifted from the loading state to the carrying state. Can be determined. That is, the first is that the vessel 21 is seated, the second is that the loaded weight G is greater than or equal to the threshold Gth, and the third is that the vehicle speed V is greater than or equal to the threshold VL for detecting travel. This is the case when the condition is satisfied. These three conditions can be called, for example, “predetermined transportation state detection conditions”.

When it is detected that the dump truck 11 has shifted to the carrying state (S33: YES), the controller 47 calculates the carrying weight G1 at the end of loading, and stores this in the storage unit 250 (S34). The carrying weight G1 at the end of loading is a carrying weight when the dump truck 11 shifts from the loading state to the carrying state.
The carrying weight G1 at the end of loading can be calculated as follows. For example, the controller 47 reads out the values of the respective loaded weights measured at predetermined times (for example, about 2 seconds) before the time t5 when the vehicle speed V exceeds the threshold value VL, respectively, and averages these values. Is calculated. The controller 47 measures the loaded weight G in real time every predetermined short period, and this measurement data is stored in the storage unit 250. The controller 47 calculates the transport weight G1 at the end of loading by averaging the loaded weights within a predetermined time immediately before the loading operation is completed and the traveling is started.

Subsequently, the controller 47 calculates a transport weight G2 during transport (S35).
For example, the controller 47 reads data of each loaded weight measured during the period (t6 to t7) during which the vehicle speed V exceeds the average detection threshold value VH from the storage unit 250, and calculates the average value thereof. By carrying out the calculation, the carrying weight G2 during carrying is calculated.
In the transportation period from time t6 to time t7, when the vehicle speed V falls below the threshold value VH, for example, the dump truck 11 often performs acceleration / deceleration or travels on rough terrain. It is done. Since the load weight measured in such a situation is considered to be low in measurement accuracy, it may be excluded when calculating the transport weight G2 during transport.
For example, if the vehicle speed V falls below the threshold value VH during the transportation period, the data measured at that time is marked and stored in the storage unit 250, and when the transportation weight G2 is calculated, the marked data is stored. It is possible not to read from the storage unit 250.

Subsequently, the controller 47 waits until the dump truck 11 shifts from the carrying state to the soiling state (S36).
For example, when the controller 47 detects a non-sitting state of the vessel 21 (a state where the vessel 21 is separated from the rear frame 28) based on a signal from the seating sensor 46, the controller 47 determines that the state has shifted to the soil removal state. Can do. Alternatively, the controller 47 determines that the state has shifted to the soil discharge state based on the operation of the lift cylinder 26 when the operator operates the soil discharge lever (not shown) to instruct the extension of the lift cylinder 26. You can also.

When the controller 47 detects that the dump truck 11 has shifted from the carrying state to the soil removal state (S36: YES), the controller 47 calculates the pre-soil weight G3 and stores it in the storage unit 250 (S37).
For example, the controller 47 reads each load weight data measured within a predetermined time (for example, 2 seconds) before the transition time t9 to the soil removal state from the storage unit 250 and calculates an average value thereof. Thus, the weight before discharging is set as G3.

When the work cycle ends, the controller 47 determines whether or not to output the transported weight based on, for example, an output instruction input from the outside (S38).
When the transport weight is output (S38: YES), the controller 47 selects at least one of the three transport weights (the transport weight G1 at the end of loading, the transport weight G2 during transport, and the transport weight G3 before discharging). One or more types of transport weights are output to the outside (S39).

  Then, the controller 47 determines whether or not all of the work has been completed (S40). If not completed (S40: NO), the controller 47 returns to S31 and repeats the above steps. Accordingly, the transport weights G1 to G3 are measured and stored in the storage unit 250 for the new work cycle. If all of the work has been completed (S40: YES), the controller 47 ends this process.

As described above, in the present embodiment, the controller 47 detects the current working state of the dump truck 11 based on the signals from the sensors 20, 22, 23, 46, and 49, respectively. be able to.
Then, the controller 47 calculates the transport weights G <b> 1 to G <b> 3 in a predetermined predetermined work state, and stores them in the storage unit 250. Moreover, the controller 47 outputs the selected transport weight among the transport weights G1 to G3 in each work state stored in the storage unit 250 to the outside.
Therefore, according to the present embodiment, an appropriate transport weight can be used according to the work environment of the dump truck 11, and the operation rate of the dump truck and the progress of work can be more appropriately managed. .

Note that the transported weight to be measured and stored is not limited to the transported weights G1, G2, and G3. In addition to this, it is possible to calculate, store and output the transport weight at any desired measurement timing.
The storage unit 250 can also store information that can be used to grasp not only the transport weight but also the progress of work. For example, when the dump truck 11 is in the loading state, each loaded weight in the loading state can be measured and stored in the storage unit 250, and can be output. Thereby, for example, work management information such as how many loads are loaded at a time by a work machine such as a wheel loader can be obtained, which can be used to improve work efficiency.

In addition, the above-mentioned process can also be expressed as follows, for example.
A dump truck 11 load weight measuring device capable of calculating the load weight of the dump truck 11 every predetermined time and storing the dump truck 11 in the storage unit 250, wherein the dump truck 11 is set in a predetermined working state (transportation state). If it is determined that the dump truck 11 has shifted to the predetermined work state (S31: YES, S32: YES, and S33: YES) Based on each loaded weight measured within a predetermined period (predetermined time before time t5) stored in the storage unit 250, the transported weight G1 before the transition immediately before the transition to the working state (at the end of loading). Step S34 in which the calculated transported weight G1 before transition is stored in the storage unit 250, and during the period when the dump truck 11 is transitioning to the predetermined working state (time t6-t7). Step S35 of calculating the transiting transport weight G2 based on each loaded weight stored in the storage unit 250, and storing the calculated transiting transport weight G2 in the storage unit 250, and the predetermined work state Step S36 for determining whether or not the state has shifted to another work state following the work state, and if it is determined that the state has shifted to another work state (S36: YES), immediately after the end of the predetermined work state The carrying weight G3 (before earthing) is calculated based on each loaded weight measured within a predetermined period (predetermined time before time t9) stored in the storage unit 250, and this carrying weight at the end. Step S37 for storing G3 in the storage unit 250, and a step for determining whether or not to output any one or more selected transported weights among the transported weights G1 to G3 stored in the storage unit 250. S38, when outputting the selected transported weight (S38: YES), reading the selected transported weight from the storage unit 250 and outputting it, and whether all the operations of the dump truck 11 have been completed The load weight measuring device for the dump truck 11 includes the step S40 for determining whether or not the above-described steps S31 to S39 are repeated until it is determined that all the operations are completed (S40: YES).

Next, a second embodiment will be described based on FIG. In the present embodiment, a limit switch 50 is provided to detect whether the equalizer bar 30 is in contact with the stopper 51.
FIG. 12 is an enlarged side view showing the vicinity of the equalizer bar. In this embodiment, a limit switch 50 is provided for detecting whether or not the equalizer bar 30 has come into contact with the stopper 51. The limit switch 50 can be provided on each stopper 51 side, for example. Alternatively, the limit switch 50 may be provided on each base 52 side. A signal from the limit switch 50 is input to the controller 47.

  The limit switch 50 can be configured as, for example, a mechanical limit switch that operates a built-in switch by expansion and contraction of a plunger. Alternatively, for example, it can be configured as a proximity switch that detects the approach of an object based on a change in a high-frequency magnetic field. Furthermore, for example, a reflective photoelectric switch or the like may be used as the limit switch. Further, instead of the limit switch 50, a strain gauge may be attached to at least one of the stopper 51 and the equalizer bar 30, and based on a signal from the strain gauge, it can be detected whether or not the contact is made.

In the following description, the term “contact” is used to include both the case where the base 52 of the equalizer bar 30 contacts the stopper 51 and the case where the base 52 approaches the stopper 51.
For example, the controller 47 can monitor whether or not the equalizer bar 30 has come into contact with the stopper 51 by checking a signal from the limit switch 50 every predetermined short time. Alternatively, a signal from the limit switch 50 can be connected to the interrupt input terminal of the controller 47, and the contact state can be detected by the generation of the interrupt input.

  When it is detected by the limit switch 50 that the equalizer bar 30 is in contact with the stopper 51, the controller 47 sets, for example, a contact determination flag stored in the storage unit 250 to “1”. Each process executed by the controller 47 refers to the contact determination flag as necessary or forcibly. Alternatively, when the contact determination flag is abolished and the contact state between the equalizer bar 30 and the stopper 51 is detected, an interrupt may be immediately applied to each program being executed.

  Then, for example, the controller 47 displays a predetermined warning message on the display device 47C or sounds a buzzer to notify the operator that the equalizer bar 30 has come into contact with the stopper 51. The controller 47 can also notify an external loading operator via the external display lamp set 48.

  When displaying the measured value of the loaded weight on the display device 47C, the controller 47 can display the fact that the equalizer bar 30 and the stopper 51 are in contact with each other. For example, the numerical value of the loaded weight measured in the contact state can be easily distinguished from other measured values measured in the normal state by displaying in red or blinking.

  In addition, when the measured value of the loaded weight is output from the printer 47B, the controller 47, for example, specifies a specific character in the vicinity of the measured value of the loaded weight measured in a state where the equalizer bar 30 and the stopper 51 are in contact with each other. And symbols (for example, * mark) can be printed. In the case of a color printer, the measured value measured in the contact state can be printed in red or the like.

  When the average value is obtained by measuring the load weight a plurality of times, the controller 47 may exclude the numerical value measured in a state where the equalizer bar 30 and the stopper 51 are in contact with each other so as not to be used in the average value calculation processing. it can. Alternatively, when the average value is calculated using a numerical value that is measured in a contact state and that may include a measurement error, the controller 47 indicates information indicating the reliability of the average value (for example, a symbol such as #). Can be output in association with this average value.

  Thus, in this embodiment, since the limit switch 50 for detecting whether or not the equalizer bar 30 has come into contact with the stopper 51 is provided, not only when the dump truck 11 is stopped at an empty load, Whether loading can be performed on the vessel 11, the dump truck 11 is traveling, or the load is being discharged from the vessel 21, it can be easily determined whether or not the load weight can be accurately measured. Usability is improved. That is, even when the dump truck 11 is in various working states (empty state, loading state, carrying state, soiling state), the reliability of the measured loaded weight can be easily determined.

In addition, this invention is not limited to each Example mentioned above. A person skilled in the art can make various additions and changes within the scope of the present invention. For example, the measurement timing of conveyance weight is not limited to G1-G3.
Moreover, although the case where one pressure sensor is provided for each suspension cylinder has been described, the present invention is not limited to this, and a plurality of pressure sensors may be provided for each suspension cylinder.
In addition, the case where the middle wheel is supported by a spring and the rear wheel is supported by a rear suspension cylinder is taken as an example, but conversely, the middle wheel is supported by a suspension cylinder and the rear wheel is supported by a spring. The present invention also applies. Furthermore, a configuration in which both the middle wheel and the rear wheel are supported by the suspension cylinder may be employed.
The articulated dump truck has been described as an example. However, the present invention is not limited to this, and the present invention is not limited to this, and is particularly applicable to other dump trucks, particularly dump trucks having a plurality of wheels supported by equalizer bars. Can be applied.
Further, the present invention can be applied not only to a configuration in which the middle wheel and the rear wheel are connected by the equalizer bar but also to a configuration in which the front wheel and the middle wheel are connected by the equalizer bar. Furthermore, the present invention can also be applied to a dump truck provided with a plurality of wheels connected by equalizer bars before and after the vehicle body.

It is a side view of the dump truck concerning the embodiment of the present invention. It is a top view which expands and shows a rear frame. It is a side view which expands and shows the equalizer bar vicinity. It is sectional drawing of a suspension cylinder. It is a block diagram which shows the circuit structure of a controller. It is a block diagram which shows the function structure of a controller. It is a flowchart which shows a calibration process. It is a flowchart which shows a loading weight measurement process. It is a flowchart which shows the work procedure of a dump truck. It is a timing chart which shows each operation state of a dump truck. It is a flowchart which shows the process which measures conveyance weight at the preset measurement timing, and memorize | stores it and outputs it. FIG. 10 is a side view of the vicinity of an equalizer bar according to the second embodiment.

Explanation of symbols

  11: Dump truck, 12: Front arm, 13: Center arm, 14: Front suspension cylinder, 15: Rear arm, 16: Rear suspension cylinder, 17: Front wheel, 18: Middle wheel, 19: Rear wheel, 20: Tilt sensor, 21: Vessel, 22: Front pressure sensor, 23: Rear pressure sensor, 24: Front car body, 25: Rear car body, 26: Lift cylinder, 27: Front frame, 28: Rear frame, 29: Pin, 30: Equalizer bar , 31: spring, 35: steering cylinder, 36: cab, 37: vessel pin, 38: piston, 39: cylinder, 39A: pressure measurement hole, 40: oil, 41: nitrogen, 42: cavity, 43: first Orifice, 44: second orifice, 45: check ball, 46: seating sensor, 4 : Controller, 47A: Manual switch, 47B: Printer, 47C: Display device, 48: External display lamp, 49: Vehicle speed sensor, 50: Limit switch, 51: Stopper, 52: Base, 110: CPU, 111: ROM, 112 : RAM, 113: Display drive circuit, 114: Communication interface, 115: Input interface, 116: Output interface, 117: Bus, 210: Calculation unit, 211: Front side load vertical direction component calculation unit, 212: Total load vertical direction Calculation unit, 213: total load calculation unit, 214: total load calculation unit, 220: front side load detection unit, 230: rear side load detection unit, 240: work state detection unit, 250: storage unit, 260: output selection unit

Claims (7)

A first step of detecting each of a plurality of work states of the dump truck;
A second step of detecting a plurality of pieces of basic information for calculating the load weight of the dump truck,
Based on the basic information detected in the second step, the loading weight of the dump truck in a predetermined plurality of predetermined working states among the respective working states detected in the first step. A third step of calculating each,
A fourth step of storing each of the calculated loading weights;
A fifth step of outputting all or part of each stored load weight;
Dump truck loading weight measurement method including   The dump truck load weight measuring method according to claim 1, wherein the fifth step outputs only the load weight in the selected predetermined work state among the load weights stored in the fourth step.   The predetermined plurality of work states include a specific work state among the respective work states detected in the first step, a state when shifting from a certain work state to the specific work state, and the specific The dump truck load weight measuring method according to claim 1, further comprising: a state when shifting from one work state to another work state. The first step detects whether the dump truck is in an empty state, a loading state, a transporting state, or an unloading state,
The third step includes a first loading weight when the dump truck is in a loading end state when the dump truck transitions from the loading state to the transportation state, and a first loading weight when the dump truck is in the transportation state. Each of the basic information detected in the second step, the two loaded weights and the third loaded weight when the dump truck is in a state before unloading when the dump truck shifts from the transported state to the unloaded state. The method for measuring the weight of a dump truck according to claim 1, wherein the weight is calculated based on each. The dump truck includes a pair of equalizer bars rotatably provided on the left and right sides of the vehicle body, first wheels supported on one side of each equalizer bar via a first suspension device, A second wheel supported on the other side of the equalizer bar via the second suspension device, and provided on the left and right sides of the vehicle body apart from the equalizer bars, respectively, and supported via the third suspension device, respectively. With a third wheel,
The second step includes
A second A step of detecting a first load applied to either one of the first suspension device or the second suspension device as one of the basic information;
A second B step of detecting a second load applied to the third suspension device as one of the basic information;
A second C step of detecting an inclination angle of the vehicle body as one of the basic information;
A second D step of calculating the loaded weight based on the first and second loads detected by the second A and second B2 steps and the inclination angle detected by the second C step; and
The method for measuring the load weight of the dump truck according to claim 1. The second D step includes
Each of the first and second suspensions is based on a ratio of a distance from each pivot center of the equalizer bar to each of the first and second suspension devices and the first load detected in the first step. A second D1 step for calculating a total load applied to the device;
A vertical load is calculated from the total load calculated in the second step D1 and the second load detected in the second step based on the tilt angle detected in the third step. A second D2 step;
A second D3 step of calculating the loaded weight by adding the vertical component of the first load and the vertical component of the second load calculated in the second D2 step;
The method for measuring the load weight of the dump truck according to claim 5. A load weight calculating means for calculating the load weight of the dump truck;
Working state detecting means for detecting each of a plurality of working states of the dump truck;
Storage means for storing each loaded weight when a plurality of predetermined work states are detected by the work state detection means among the plurality of load weights respectively calculated by the load weight calculation means;
An output selection means for reading out and outputting a load weight in a predetermined work state selected from the plurality of predetermined work states;
Dump truck loading weight measuring device equipped with.

Images