Hydraulic excavator

Abstract

To provide a hydraulic excavator that can load materials evenly into the loading area without requiring sensors or other devices to be installed on the loading side. [Solution] The hydraulic excavator identifies the bucket's position based on the detection results of position sensors and attitude sensors. It divides the loading area indicated by the identified bucket's position into multiple sub-regions. When it is determined that the loaded material has been discharged from the bucket within the loading area, it adds the measured weight of the loaded material to the sub-region overlapping the identified bucket's position and displays the weight of the loaded material in each of the sub-regions on the display.

Description

Technical Field

[0001] The present invention relates to a hydraulic excavator for measuring the weight of a loaded material.

Background Art

[0007] To achieve the above objective, the present invention provides a working device comprising a lower traveling body, an upper rotating body rotatably supported on the lower traveling body, a boom rotatably supported on the upper rotating body, an arm rotatably supported at the tip of the boom, a bucket rotatably supported at the tip of the arm, and a hydraulic cylinder for rotating the boom, a posture sensor for detecting the posture of the working device, a pressure sensor for detecting the pressure of the hydraulic fluid in the hydraulic cylinder, a display for displaying information, and based on the posture of the working device detected by the posture sensor and the pressure of the hydraulic fluid detected by the pressure sensor, the bucket... A hydraulic excavator comprising a controller for measuring the weight of a load contained in a bucket is further provided with a position sensor for detecting the position of the hydraulic excavator, wherein the controller identifies the position of the bucket based on the detection results of the position sensor and the attitude sensor, divides the loading area indicated by the identified bucket position into a plurality of sub-regions, and when it is determined that a load has been discharged from the bucket within the loading area, adds the measured weight of the load to the sub-region that overlaps with the identified bucket position, and displays the weight of the load in each of the plurality of sub-regions on the display. [Effects of the Invention]

[0008] According to the present invention, it is possible to obtain a hydraulic excavator that can load materials into the loading area in a balanced manner without having to attach sensors or the like to the side where the materials are loaded. Other problems, configurations, and effects will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of a hydraulic excavator. [Figure 2] This is a hardware configuration diagram for a hydraulic excavator. [Figure 3] This is a functional block diagram of the controller. [Figure 4] This diagram shows the relationship between the posture of the front work implement and the detection results of various sensors. [Figure 5] This is a flowchart for the loading area identification process. [Figure 6] This is an example of the loading area identification screen. [Figure 7] This is a flowchart for the loading status notification process. [Figure 8] This is an example of the loading status notification screen. [Figure 9] This is a flowchart for the leveling status notification process. [Figure 10] This is an example of the display screen showing the leveling status before the leveling operation is performed. [Figure 11] This is an example of the display screen showing the leveling status after the leveling operation has been performed. [Figure 12] This is a diagram illustrating a modified example of step S39. [Modes for carrying out the invention]

[0010] [Configuration of Hydraulic Excavator 1] An embodiment of the hydraulic excavator 1 according to the present invention will be described with reference to the drawings. In this specification, unless otherwise specified, the front, back, left, and right directions are based on the viewpoint of the operator riding and operating the hydraulic excavator 1.

[0011] Figure 1 is a side view of a hydraulic excavator 1. As shown in Figure 1, the hydraulic excavator 1 comprises a lower traveling body 2 and an upper rotating body 3 supported by the lower traveling body 2. The lower traveling body 2 and the upper rotating body 3 are examples of the machine body.

[0012] The lower vehicle 2 is equipped with a pair of crawlers 4 on the left and right sides, which are continuous tracks. Driven by the travel motor 5, the pair of crawlers 4 rotate independently. As a result, the hydraulic excavator 1 moves. However, the lower vehicle 2 may be wheeled instead of having crawlers 4.

[0013] The upper revolving body 3 is supported by the lower traveling body 2 so as to be rotatable. Then, when the swing motor 6 rotates, the upper revolving body 3 rotates with respect to the lower traveling body 2. The upper revolving body 3 mainly includes a revolving frame 7 serving as a base, a cab (driver's seat) 8 disposed on the front left side of the revolving frame 7, a counterweight 9 disposed at the rear of the revolving frame 7, and a front working machine 10 (working device) vertically rotatably attached to the front center of the revolving frame 7.

[0014] The cab 8 is disposed adjacent to the front working machine 10 in the left - right direction (width direction of the vehicle body). More specifically, the cab 8 is disposed on the left side (one side in the left - right direction) of the front working machine 10. However, the arrangement of the cab 8 is not limited to the above example, and the cab 8 may be disposed on one side of the front working machine 10 in the left - right direction.

[0015] A space for an operator to board and operate the hydraulic excavator 1 is formed in the cab 8. Inside the cab 8, a seat on which the operator sits and an operating device 33 (see FIG. 2) operated by the operator sitting on the seat are disposed. The operating device 33 receives the operation of the operator for operating the hydraulic excavator 1. When the operating device 33 is operated by the operator, the lower traveling body 2 travels, the upper revolving body 3 rotates, and the front working machine 10 operates. Specific examples of the operating device 33 include a lever, a steering wheel, a pedal, a switch, etc.

[0016] The front work implement 10 includes a boom 11 supported on the upper slewing body 3 so as to be rotatable around a pivot center X1 (see Figure 4), an arm 12 supported at the tip of the boom 11 so as to be rotatable around a pivot center X2 (see Figure 4), a bucket 13 (attachment) supported at the tip of the arm 12 so as to be rotatable around a pivot center X3 (see Figure 4), a boom cylinder 14 for rotating the boom 11 relative to the upper slewing body 3, an arm cylinder 15 for rotating the arm 12 relative to the boom 11, and a bucket cylinder 16 for rotating the bucket 13 relative to the arm 12. The counterweight 9 is for balancing the weight with the front work implement 10 and is a heavy object with an arc shape when viewed from above.

[0017] The boom cylinder 14, as shown in Figure 4, is an example of a hydraulic cylinder comprising a cylinder tube 14a, a piston (not shown), and a cylinder rod 14b. The cylinder tube 14a is a cylindrical member with one end closed and the other end open. The piston is configured to move within the cylinder tube 14a. The piston also divides the internal space of the cylinder tube 14a into a bottom chamber and a rod chamber. One end of the cylinder rod 14b is connected to the piston, and the other end protrudes from the open end of the cylinder tube 14a. The configurations of the arm cylinder 15 and the bucket cylinder 16 are similar.

[0018] In the internal space of the cylinder tube 14a, which is partitioned by a piston, the space opposite the cylinder rod 14b is referred to as the "bottom chamber," and the space on the cylinder rod 14b side is referred to as the "rod chamber." The closed end of the cylinder tube 14a is rotatably supported by the upper slewing body 3, and the tip of the cylinder rod 14b is rotatably supported by the boom 11. When hydraulic fluid is supplied to the bottom chamber and discharged from the rod chamber, the boom cylinder 14 extends (i.e., the boom 11 rises). Conversely, when hydraulic fluid is discharged from the bottom chamber and supplied to the rod chamber, the boom cylinder 14 retracts (i.e., the boom 11 collapses).

[0019] The bucket 13 has a space that can accommodate the material to be loaded (for example, soil, gravel). The bucket 13 can then rotate at the tip of the arm 12 to scoop up the material (so-called clouding action) and discharge the scooped material (so-called dumping action). Hereafter, the material scooped up by the bucket 13 will be referred to as "soil."

[0020] [Hardware configuration of hydraulic excavator 1] Figure 2 is a hardware configuration diagram of the hydraulic excavator 1. As shown in Figure 2, the hydraulic excavator 1 includes a controller 30 having a CPU 31 (Central Processing Unit) and memory 32. The memory 32 is composed of, for example, ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), or a combination thereof. The controller 30 performs the processing described later by having the CPU 31 read and execute the program code stored in the memory 32.

[0021] However, the specific configuration of the controller 30 is not limited to this and may be implemented using hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array).

[0022] The controller 30 controls the operation of the entire hydraulic excavator 1. Based on various signals output from the operating device 33, vertex designation switch 34, GPS antennas 35a, 35b, pressure sensors 36b, 36r, and angle sensors 37, 38, 39, the controller 30 controls the operation of hydraulic actuators (e.g., travel motor 5, slewing motor 6, boom cylinder 14, arm cylinder 15, bucket cylinder 16) through the hydraulic circuit 40 and displays various information on the display 41.

[0023] The operating device 33 receives an operation from an operator to instruct the operation of the hydraulic actuator and outputs an operation signal corresponding to the operator's operation to the controller 30. The controller 30 operates the hydraulic actuator by controlling the hydraulic circuit 40 according to the operation signal output from the operating device 33.

[0024] The vertex designation switch 34 accepts operator input and outputs a vertex signal to the controller 30. The controller 30 stores the position of the bucket 13 at the time the vertex signal is output from the vertex designation switch 34 as the vertex position of the loading area 50 (described later) in the memory 32. This process will be described later with reference to Figure 5.

[0025] The GPS (Global Positioning System) antennas 35a and 35b receive signals from GPS satellites and output a position signal indicating the current position of the hydraulic excavator 1 to the controller 30. The GPS antennas 35a and 35b are examples of position sensors that detect the current position of the hydraulic excavator 1. The position signal includes, for example, the latitude and longitude of the positions of the GPS antennas 35a and 35b. The GPS antennas 35a and 35b are positioned at a distance from each other when the upper rotating body 3 is viewed from above in a plan view. That is, the current position detected by the GPS antennas 35a and 35b is shifted by the distance between the GPS antennas 35a and 35b.

[0026] The controller 30 determines the position of the hydraulic excavator 1 based on the position signals output from the GPS antennas 35a and 35b. The controller 30 also determines the orientation of the hydraulic excavator 1 (more specifically, the upper rotating body 3) based on the difference in current positions detected by the GPS antennas 35a and 35b. However, the method for detecting the orientation of the hydraulic excavator 1 is not limited to the example described above; any configuration is acceptable as long as the position and orientation of the hydraulic excavator 1 can be determined, such as combining the GPS antenna 35a with a rotation angle sensor that detects the rotation angle of the upper rotating body 3.

[0027] Pressure sensor 36b detects the hydraulic fluid pressure Pb in the bottom chamber of the boom cylinder 14 and outputs a pressure signal indicating the detected pressure Pb to the controller 30. Pressure sensor 36r detects the hydraulic fluid pressure Pr in the rod chamber of the boom cylinder 14 and outputs a pressure signal indicating the detected pressure Pr to the controller 30.

[0028] Angle sensor 37 detects the angle of the boom 11 with respect to the upper slewing body 3 (in other words, the mounting surface of the hydraulic excavator 1) (boom angle α) and outputs an angle signal indicating the detected boom angle α to the controller 30. Angle sensor 38 detects the angle of the arm 12 with respect to the boom 11 (arm angle β) and outputs an angle signal indicating the detected arm angle β to the controller 30. Angle sensor 39 detects the angle of the bucket 13 with respect to the arm 12 (bucket angle γ) and outputs an angle signal indicating the detected bucket angle γ to the controller 30. Angle sensors 37 to 39 are examples of attitude sensors that detect the attitude of the front work implement 10.

[0029] The hydraulic circuit 40 is a circuit that operates a hydraulic actuator (more specifically, supplies and discharges hydraulic fluid to the hydraulic actuator) according to the control of the controller 30. The hydraulic circuit 40 includes, for example, a hydraulic fluid tank for storing hydraulic fluid, a hydraulic pump for discharging the hydraulic fluid stored in the hydraulic fluid tank, a directional control valve for controlling the amount and direction of supply of hydraulic fluid discharged from the hydraulic pump to the hydraulic actuator, and a relief valve for discharging hydraulic fluid to the hydraulic fluid tank when the pressure of the hydraulic fluid supplied to the hydraulic actuator reaches a threshold. The configuration of the hydraulic circuit 40 is well known, so a detailed explanation is omitted.

[0030] Display 41 is an example of a display device that shows information to the operator in the cab 8. Display 41 may show, for example, the loading area determination screen shown in Figure 6, the loading status notification screen shown in Figure 8, and the leveling status notification screen shown in Figures 10 and 11.

[0031] [Functional blocks of controller 30] Figure 3 is a functional block diagram of the controller 30. Figure 4 is a diagram showing the relationship between the posture of the front work machine 10 and the detection results of various sensors. As shown in Figure 3, the controller 30 includes a posture detection unit 51, a weight measurement unit 52, a bucket position identification unit 53, a loading area identification unit 54, a weight addition unit 55, a leveling area identification unit 56, and a weight update unit 57. The controller 30 functions as the posture detection unit 51, weight measurement unit 52, bucket position identification unit 53, loading area identification unit 54, weight addition unit 55, leveling area identification unit 56, and weight update unit 57 by the CPU 31 executing a program stored in the memory 32.

[0032] The posture detection unit 51 detects the posture of the front work implement 10 based on the angles α, β, and γ detected by the angle sensors 37-38 and the various dimensions of the front work implement 10 (boom 11, arm 12, bucket 13). More specifically, as shown in Figure 4, the posture detection unit 51 detects the horizontal length lbm from the pivot center X1 to the center position of the bucket 13 (in other words, the center of gravity of the soil contained in the bucket 13), the length hbm of the perpendicular line passing through the pivot center X1 to the boom 11, and the horizontal length l1 from the pivot center X1 to the center of gravity of the front work implement 10 excluding the boom cylinder 14. The posture detection unit 51 detects the various lengths lbm, hbm, and l1 [m] by inputting the angles α, β, and γ [degrees] into a predetermined mathematical formula, for example. However, the specific method for detecting the various lengths lbm, hbm, and l1 is not limited to the example described above.

[0033] The weight measurement unit 52 measures the weight W [kgf] of the soil contained in the bucket 13 based on the posture (lbm, hbm, l1) of the front work implement 10 detected by the posture detection unit 51 and the pressures Pb and Pr [Pa] detected by the pressure sensors 36b and 36r. The weight measurement unit 52 measures the weight W of the soil using, for example, the following equations 1 to 3 and displays the measured weight W on the display 41. The weight measurement unit 52 measures the weight W when the static friction force R, which will be described later, is as close to 0 as possible. In addition to being displayed on the display 41, the weight W measured by the weight measurement unit 52 can also be used for the loading status notification process (Figure 7) and leveling status notification process (Figure 9), which will be described later. Fbm=Pb×Ab-Pr×Ar-R (Formula 1) Fbm×hbm=W×lbm+W1×l1 (Formula 2) W=(Fbm×hbm-W1×l1) / lbm (Formula 3)

[0034] Fbm[kgf] is the thrust in the direction of extending the boom cylinder 14, Ab[m 2 ] is the pressure-receiving area on the bottom chamber side of the piston, Ar[m 2 ] is the pressure-receiving area on the rod chamber side of the piston, R[kgf] is the static friction force of the boom cylinder 14, and W1[kgf] is the weight of the front work implement 10. The pressure-receiving areas Ab, Ar and the weight W1 are stored in memory 32 beforehand. Equation 1 is the formula for calculating the thrust Fbm of the boom cylinder 14 based on the pressures Pb and Pr detected by the pressure sensors 36b and 36r. Equation 2 is the formula showing the balance of moments around the front work implement 10. Equation 3 is the formula obtained by solving Equation 2 for weight W.

[0035] The bucket positioning unit 53 uses the position signals output from GPS antennas 35a and 35b, the attitude of the front work implement 10 detected by the attitude detection unit 51 (e.g., length in lbm), and various dimensions of the hydraulic excavator 1 (e.g., the horizontal distance from the installation position of GPS antenna 35a to the rotation center X1) to determine the position of the bucket 13 (a combination of latitude and longitude of the bucket 13's position). Alternatively, the bucket positioning unit 53 may determine the position of the bucket 13 using the angle signals output from angle sensors 37-39 and various dimensions of the front work implement 10 instead of the detection result of the attitude detection unit 51. The bucket positioning unit 53 can, for example, determine the position of the bucket 13 by substituting the position signals and angle signals into a predetermined mathematical formula.

[0036] The loading area identification unit 54 identifies the loading area 60 (see Figure 8) where the soil contained in the bucket 13 will be loaded, based on the position of the bucket 13 identified by the bucket position identification unit 53 and the vertex signal output from the vertex designation switch. The loading area 60 is, for example, the area of ​​the cargo bed when the dump truck is viewed from above in a plan view. In addition, the loading area 60 in this embodiment is assumed to be rectangular (for example, a rectangle), but the shape of the loading area 60 is not particularly limited.

[0037] Furthermore, the loading area identification unit 54 divides the identified loading area 60 into a plurality of sub-regions 60a to 60l (see Figure 8). The area of ​​each sub-region 60a to 60l is set to be, for example, equivalent to or slightly larger than the area of ​​the bucket 13 viewed from above in plan. The sub-regions 60a to 60l are set to be, for example, identical in shape and area (i.e., contiguous). The loading area identification unit 54 divides the loading area 60 into sub-regions 60a to 60l such that, among contiguous shapes that are larger than or equal to the area of ​​the bucket 13 viewed from above, the area is the smallest. However, the specific method of dividing the loading area 60 into sub-regions 60a to 60l is not limited to the example described above.

[0038] When soil is discharged from the bucket 13 within the loading area 60 (i.e., a dump operation is performed), the weight addition unit 55 adds the weight W measured by the weight measurement unit 52 to the small areas 60a to 60l that overlap with the position of the bucket 13 identified by the bucket position identification unit 53. In other words, as the hydraulic excavator 1 repeatedly performs dump operations, the weight addition unit 55 individually accumulates the weight W of the soil discharged into the loading area 60 for each of the small areas 60a to 60l. Furthermore, as shown in Figure 8, for example, the weight addition unit 55 displays the individually accumulated weights of each of the small areas 60a to 60l on the display 41.

[0039] For example, the weight addition unit 55 may determine that a dump operation has been performed when the bucket angle γ detected by the angle sensor 39 reaches a predetermined angle. As another example, the weight addition unit 55 may determine that a dump operation has been performed when the weight W measured by the weight measurement unit 52 decreases from a positive value to a predetermined value or less (typically 0). The specific method for determining that a dump operation has been performed is not limited to the examples described above.

[0040] The leveling area identification unit 56 determines that a leveling operation has been performed based on the weight W measured by the weight measurement unit 52 and the position of the bucket 13 identified by the bucket position identification unit 53, and identifies the multiple small areas 60c, 60d, 60e, 60j, and 60k (see Figure 11) that the bucket 13 passed through during the leveling operation. The leveling operation is the operation of leveling the soil and sand loaded into the small areas 60a to 60l with the bucket 13. In other words, the leveling operation is the operation of moving the bucket 13 within the loading area 60 while pressing the bucket 13 against the soil and sand within the loading area 60. For example, the leveling area identification unit 56 determines that a leveling operation has been performed when the weight measured by the weight measurement unit 52 is a negative value and the bucket 13 identified by the bucket position identification unit 53 is moving within the loading area 60.

[0041] The weight update unit 57, for example, averages the weights Wc, Wd, We, Wj, and Wk of the soil in the small areas 60c, 60d, 60e, 60j, and 60k identified by the leveling area identification unit 56, from the weight accumulated in each small area 60a to 60l by the weight addition unit 55, and redistributes them to the small areas 60c, 60d, 60e, 60j, and 60k. In this embodiment, the weight update unit 57 simply averages the weights Wc, Wd, We, Wj, and Wk accumulated in the small areas 60c, 60d, 60e, 60j, and 60k and redistributes them to the small areas 60c, 60d, 60e, 60j, and 60k. However, the weight update method by the weight update unit 57 is not limited to the example described above. Other examples of weight update methods will be explained in the following modified examples 1 and 2.

[0042] [Loading area identification process] Figure 5 is a flowchart of the loading area identification process. Figure 6 is an example of the loading area identification screen display. The loading area identification process is the process of identifying the loading area 60 into which the soil contained in the bucket 13 will be loaded. More specifically, the loading area identification process is the process of identifying the outline of the loading area 60 by having the operator specify the position of the vertex of the loading area 60 with the tip of the bucket 13. The controller 30 executes the loading area identification process when instructed by the operator via the operating device 33. At the start of the loading area identification process, it is assumed that the dump truck is parked in a position where the hydraulic excavator 1 can load soil onto the truck bed with the bucket 13.

[0043] First, the loading area identification unit 54 displays the loading area identification screen shown in Figure 6 on the display 41. The loading area identification screen includes a schematic diagram of the dump truck viewed from above, the vertices A, B, C, and D of the dump truck's cargo bed, and an arrow 61 indicating the position of the next vertex to be designated (vertex A in the example in Figure 8). In this embodiment, the loading area 60 is assumed to be a rectangle having four vertices A, B, C, and D. Also, from the perspective of the hydraulic excavator 1, vertex A is located in the back left corner, vertex B in the back right corner, vertex C in the front left corner, and vertex D in the front right corner.

[0044] The operator in cab 8 operates the control device 33 to position the bucket 13 in the left rear corner of the loading platform, corresponding to vertex A indicated by arrow 61. Then, with the bucket 13 positioned directly above the left rear corner of the loading platform, the operator operates the vertex designation switch 34. At the moment the vertex signal is output from the vertex designation switch 34 (S11: Yes), the loading area identification unit 54 stores the position of the bucket 13, identified by the bucket position identification unit 53, in memory 32 as the position of vertex A (XA, YA) indicated by arrow 61 (S12).

[0045] Next, the bucket position identification unit 53 determines whether or not the operator has specified all vertices A, B, C, and D of the loading area 60 (S13). If the bucket position identification unit 53 determines that not all vertices have been specified (S13: No), it moves the arrow 61 on the loading area identification screen to the next vertex B and executes the process from step S11 onwards again. That is, the bucket position identification unit 53 causes the operator to sequentially specify the positions of vertex A (XA, YA), vertex B (XB, YB), vertex C (XC, YC), and vertex D (XD, YD) using the bucket 13.

[0046] Next, if the bucket position identification unit 53 determines that all vertices A, B, C, and D have been specified (S13: Yes), it identifies the area enclosed by the specified vertices A, B, C, and D as the loading area 60. That is, the bucket position identification unit 53 uses the bucket 13 to teach the operator the loading area 60. Next, the bucket position identification unit 53 divides the identified loading area 60 into a plurality of sub-regions 60a to 60l (S14). Then, the bucket position identification unit 53 stores the positions of each vertex in the plurality of sub-regions 60a to 60l in the memory 32.

[0047] [Loading status notification processing] Figure 7 is a flowchart of the loading status notification process. Figure 8 is an example of the loading status notification screen display. The loading status notification process is a process that notifies the operator of the state of the soil loaded onto the dump truck bed (i.e., the loading area 60) (more specifically, the weight balance of the loading area 60). The controller 30 repeatedly executes the loading status notification process at predetermined control cycles when instructed by the operator via the control device 33. It is assumed that the loading area identification process has already been completed at the start of the first loading status notification process.

[0048] First, the weight addition unit 55 displays the loading status notification screen shown in Figure 8 on the display 41. The loading status notification screen includes the loading area 60, which has been divided into multiple sub-regions 60a to 60l by the loading area identification process; a marker 62 (in the example of Figure 8, "+") indicating the position of the bucket 13 identified by the bucket position identification unit 53; the weight W of the soil contained in the bucket 13 (for example, 80 kg); the total weight of soil that can be loaded onto a dump truck parked near the hydraulic excavator 1 (for example, 5 t); and the current weight of soil loaded onto the truck bed at this time (for example, 750 kg).

[0049] Vertices A, B, C, and D on the loading status notification screen are assigned the positions (XA, YA), (XB, YB), (XC, YC), and (XD, YD) identified in the loading area identification process. In addition, the marker 62 on the loading status notification screen is placed at the position of the bucket 13 identified in step S23. That is, the loading status notification screen displays the positional relationship of the actual dump truck bed and bucket 13 as viewed from above, but scaled down (typically reduced). The marker 62 may also be sized to correspond to the area of ​​the bucket 13 as viewed from above (the actual area scaled down to match the size of the loading area 60).

[0050] The weight W (=80kg) is a value measured in step S21 and may move along with the marker 62. The total weight (=5t) may be obtained, for example, by communication with the dump truck, or it may be entered by an operator who has visually confirmed the dump truck through the control device 33. The current weight (=750kg) is the sum of the weights of the soil loaded into the loading area 60 during the repeatedly executed loading status notification process, and is 0 at the start of the first loading status notification process.

[0051] Furthermore, the weights Wa to Wl of the soil loaded into each of the small areas 60a to 60l are stored in memory 32 and are 0 at the start of the initial loading status notification process. In addition, in the loading status notification screen shown in Figure 8, the weights Wa to Wl of the soil stored in memory 32 are represented by the intensity of the color of each cell representing the small areas 60a to 60l. That is, in Figure 8, the darker the color of the small areas 60b and 60c, the larger the weights Wb and Wc, and the lighter the color of the small areas 60f and 60l, the lighter the weights Wf and Wl. However, the weight addition unit 55 may display the weights Wa to Wl as numerical values ​​in each cell instead of representing them by the intensity of the color of each cell.

[0052] Next, the weight measurement unit 52 measures the weight W of the soil contained in the bucket 13 (S21). The weight addition unit 55 determines that the bucket 13 contains soil if the weight W measured by the weight measurement unit 52 is equal to or greater than a threshold (S22: Yes), and executes the processing from step S23 onwards. On the other hand, the weight addition unit 55 determines that the bucket 13 does not contain soil if the measured weight W is less than the threshold (S22: No), and terminates the loading status notification process without executing the processing from step S23 onwards.

[0053] Next, the bucket position identification unit 53 identifies the position of the bucket 13 (S23). The bucket position identification unit 53 also moves the marker 62 on the loading status notification screen in accordance with the position of the bucket 13 identified in step S23. Furthermore, the weight addition unit 55 executes the processing from step S25 onwards if the position of the bucket 13 identified by the bucket position identification unit 53 is within the loading area 60 (S24: Yes). On the other hand, if the position of the bucket 13 identified by the bucket position identification unit 53 is outside the loading area 60 (S24: No), the weight addition unit 55 terminates the loading status notification processing without executing the processing from step S25 onwards.

[0054] Next, the weight addition unit 55 detects the state of the bucket 13 (S25). If the weight addition unit 55 determines that the dumping operation has not been performed (S26: No), it terminates the loading status notification process without executing the process in step S27. On the other hand, if the weight addition unit 55 determines that the dumping operation has been performed (S26: Yes), it determines that the soil contained in the bucket 13 has been discharged into the loading area 60 and executes the process in step S27.

[0055] In other words, in step S27, the weight addition unit 55 determines that soil has been discharged into a small area (for example, small area 60c) that overlaps with the position of the bucket 13 identified in step S23. The weight addition unit 55 also adds the weight W measured in step S21 to the weight Wc stored in memory 32. The weight addition unit 55 also changes the color of the square in small area 60c on the loading status notification screen to match the updated weight Wc. Furthermore, the weight addition unit 55 adds the weight W measured in step S21 to the current weight on the loading status notification screen.

[0056] The controller 30 then repeatedly performs loading status notification processing at predetermined control cycles until the loading of the soil is instructed to be completed via the operating device 33. That is, the weight addition unit 55 accumulates the weight W of the soil loaded from the bucket 13 into the loading area 60 for each of the multiple small areas 60a to 60l. The weight addition unit 55 also notifies the weight balance of the small areas 60a to 60l through the loading status notification screen. Therefore, the operator in the cab 8 only needs to determine the position on the loading area 60 from which the soil from the bucket 13 should be discharged (for example, small areas 60f and 60l in the example in Figure 8) while looking at either or both the actual dump truck and the loading status notification screen, so as to equalize the weight balance of the cargo bed.

[0057] Even if the loading of soil is performed while monitoring the loading status notification screen, as shown in Figure 8, an imbalance in the weight distribution of the soil may occur in the small area 60a to 60l. Therefore, the operator of the hydraulic excavator 1 may perform a leveling operation after the loading of soil onto the dump truck is complete to retrospectively equalize the weight distribution of the soil within the loading area 60.

[0058] [Leveling status notification processing] Figure 9 is a flowchart of the leveling status notification process. Figure 10 is an example of the leveling status notification screen display before the leveling operation is performed. Figure 11 is an example of the leveling status notification screen display after the leveling operation is performed. The leveling status notification process is a process that notifies the operator that the weights Wa to Wl of the small area 60a to 60l have been leveled by the leveling operation. The controller 30 repeatedly executes the leveling status notification process at predetermined control cycles when instructed by the operator through the operating device 33.

[0059] It is assumed that the loading area identification process and the loading status notification process have already been completed at the start of the initial leveling status notification process. Furthermore, memory 32 stores a leveling operation flag indicating whether or not a leveling operation has been performed. The leveling operation flag is set to either a first value "OFF" indicating that the leveling operation has not been performed, or a second value "ON" indicating that the leveling operation has been performed. Additionally, it is assumed that the leveling operation flag is initially set to the value "OFF" at the start of the initial leveling status notification process.

[0060] First, the leveling area identification unit 56 displays the leveling status notification screen shown in Figure 10 on the display 41. The leveling status notification screen includes the loading area 60, which has been divided into multiple sub-regions 60a to 60l by the loading area identification process, the weights Wa to Wl for each sub-region 60a to 60l accumulated by the loading status notification process, and a marker 63 indicating the position of the bucket 13 identified by the bucket position identification unit 53. The weights Wa to Wl are the values ​​at the end of the repeatedly executed loading status notification process and are represented by the intensity of each cell in the sub-regions 60a to 60l.

[0061] Vertices A, B, C, and D on the leveling status notification screen are assigned the positions (XA, YA), (XB, YB), (XC, YC), and (XD, YD) identified in the loading area identification process. Marker 63 on the leveling status notification screen is placed at the position of the bucket 13 identified in step S31. In other words, the leveling status notification screen displays the positional relationship of the actual dump truck bed and bucket 13 as viewed from above, but scaled down (typically reduced). Marker 63 is an "I" shape, for example, corresponding to the length of the bucket 13 in the left-right direction when viewed from above (the actual length is scaled down to match the size of the loading area 60).

[0062] Next, the bucket position identification unit 53 identifies the position of the bucket 13 (S31). Next, the weight measurement unit 52 measures the weight W of the soil contained in the bucket 13 (S32). Next, the leveling area identification unit 56 determines whether the position of the bucket 13 identified in step S31 is within the loading area 60 (S33). If the leveling area identification unit 56 determines that the position of the bucket 13 is outside the loading area 60 (S33: No), it terminates the leveling status notification process without executing the process in step S34.

[0063] On the other hand, the leveling area identification unit 56 determines whether the weight W measured in step S32 is less than 0 (i.e., a negative value) if it determines that the position of the bucket 13 is within the loading area 60 (S33:Yes). Note that the case where the position of the bucket 13 is within the loading area 60 and the weight W is less than 0 (S33:Yes & S34:Yes) refers to a state in which the bucket 13 is pressed against the soil loaded in the loading area 60.

[0064] Next, the leveling area identification unit 56 determines that the bucket 13 is located within the loading area 60 and that its weight W is less than 0 (S33:Yes & S34:Yes), sets the leveling operation flag to the second value "ON" (S35), and stores the position of the bucket 13 identified in step S31 in the memory 32 as the position that the bucket 13 has passed through during the leveling operation (S36). The leveling area identification unit 56 also moves the marker 63 on the leveling status notification screen in accordance with the position of the bucket 13 identified in step S31.

[0065] The operator operates the control device 33 while viewing either the actual dump truck or the leveling status notification screen, or both, to ensure that the bucket 13 passes through small areas with a large weight of soil (in the example in Figure 10, small areas 60b and 60c). The leveling area identification unit 56 repeatedly executes steps S31 to S36 until the weight W becomes 0 or greater (S34: No). As a result, the memory 32 stores the positions that the bucket 13 has passed through during the leveling operation in chronological order. The position stored in step S36 may be, for example, the center position in the front-to-back direction of the marker 63.

[0066] Next, the leveling area identification unit 56 determines if the bucket 13 is located within the loading area 60 and its weight W is 0 or greater (S33: Yes & S34: No), and determines the setting value of the leveling operation flag (S37). Then, if the leveling area identification unit 56 determines that the leveling operation flag is set to the first value "OFF" (S37: No), it terminates the leveling status notification process without executing the processes from step S38 onwards.

[0067] On the other hand, the leveling area identification unit 56 determines that the weight W is 0 or greater and the leveling operation flag is set to the second value "ON" (S34: No & S37: Yes), and identifies the small areas (in the example of Figure 11, small areas 60c, 60d, 60e, 60j, 60k) that the bucket 13 has passed through during the leveling operation, based on the position of the bucket 13 stored in memory in the repeatedly executed step S36 (S38). The condition that the weight W is 0 or greater and the leveling operation flag is set to the second value "ON" (S34: No & S37: Yes) refers to the state in which the bucket 13 has separated from the soil in the loading area 60 and the leveling operation has been completed.

[0068] The leveling area identification unit 56 extends the position of the bucket 13 stored in the memory 32 in step S36 in the front-rear direction to correspond to the size of the bucket 13, as shown by the marker 63 in Figure 10. The leveling area identification unit 56 then performs this process for all positions stored in the memory 32, thereby identifying the area shown by the dashed line in Figure 11. The leveling area identification unit 56 then identifies the small areas 60c, 60d, 60e, 60j, and 60k that overlap the area shown by the dashed line in Figure 11 as the small areas that the bucket 13 passed through during the leveling operation (i.e., the areas where the soil has been leveled).

[0069] Next, the weight update unit 57 averages the weights Wc, Wd, We, Wj, and Wk of the sub-regions 60c, 60d, 60e, 60j, and 60k identified in step S38, as shown in Equation 4 below (S39). In Equation 4, n refers to the number of sub-regions identified in step S38. The weight update unit 57 also updates the weights Wc, Wd, We, Wj, and Wk of the sub-regions 60c, 60d, 60e, 60j, and 60k identified in step S38 to the average value W' (S40). W'=(W1+W2+...+Wn) / n...(Formula 4)

[0070] In other words, the weight update unit 57 averages the weights Wc, Wd, We, Wj, and Wk of the sub-regions 60c, 60d, 60e, 60j, and 60k identified in step S38 and reallocates them to the sub-regions 60c, 60d, 60e, 60j, and 60k. As a result, the weights Wc, Wd, We, Wj, and Wk after step S38 become the same value (=W'). Also, as shown in Figure 11, the weight update unit 57 changes the display pattern of the cells in the sub-regions 60c, 60d, 60e, 60j, and 60k to match the updated weights Wc, Wd, We, Wj, and Wk.

[0071] Furthermore, the weight update unit 57 sets the leveling operation flag to the first value "OFF" (S41), deletes the position of the bucket 13 stored in the memory 32 in step S36 (S42), and terminates the leveling status notification process.

[0072] [Effects of the Embodiment] According to the above embodiment, the loading area 60, as instructed by the bucket 13, is divided into multiple sub-areas 60a to 60l. The weight W of the soil loaded into the loading area 60 by the dumping operation is accumulated for each sub-area 60a to 60l, and the accumulated result is displayed on the display 41. As a result, by operating the hydraulic excavator 1 while viewing the loading status notification screen, soil can be loaded into the loading area 60 in a balanced manner without the need to attach sensors or the like to the dump truck.

[0073] Furthermore, according to the above embodiment, when the soil in the loading area 60 is leveled by the leveling operation, the weights Wc, Wd, We, Wj, and Wk of the small areas 60c, 60d, 60e, 60j, and 60k that the bucket 13 has passed through are averaged and redistributed. This allows the operator to confirm the results of the leveling operation, enabling them to load the soil into the loading area 60 in a more balanced manner.

[0074] [Example of step S39] Figure 12 is a diagram illustrating a modified example of step S39. Detailed explanations of the similarities with the above embodiment will be omitted, and the focus will be on the differences. In this modified example, the calculation method in step S39 differs from that of the above embodiment, while other aspects are the same as those of the above embodiment.

[0075] The weight update unit 57 in the modified example identifies the percentages Rc, Rd, Re, Rj, and Rk of the area passed by the bucket 13 for each of the small regions 60c, 60d, 60e, 60j, and 60k that the bucket 13 passed through during the leveling operation. That is, the weight update unit 57 identifies the percentages Rc, Rd, Re, Rj, and Rk of the overlapping areas of the dashed lines identified in step S38 for each of the small regions 60c, 60d, 60e, 60j, and 60k. In the example in Figure 12, the following process is explained assuming Rc=80%, Rd=85%, Re=70%, Rj=2%, and Rk=3%.

[0076] In Modification 1, the weight update unit 57 averages the weights Wc, Wd, and We of only the sub-regions 60c, 60d, and 60e where the proportion of the area Rc, Rd, Re, Rj, Rk passed by the bucket 13 is greater than or equal to a threshold (for example, 10%), and redistributes them to the sub-regions 60c, 60d, and 60e. In other words, in Modification 1, of the sub-regions 60c, 60d, and 60e passed by the bucket 13, only the soil in sub-regions 60c, 60d, and 60e is considered to be leveled, while the soil in sub-regions 60j and 60k is considered not to be leveled.

[0077] Furthermore, the weight update unit 57 in the modified example 2 redistributes the weights Wc, Wd, We, Wj, and Wk of the multiple small regions 60c, 60d, 60e, 60j, and 60k that the bucket 13 has passed through during the leveling operation, weighted and averaged according to the proportion of the area that the bucket 13 has passed through, as shown in equations 5 and 6 below. That is, in the example above, the weights Wc, Wd, We, Wj, and Wk are substituted for W1, W2, ..., Wn in equation 5, and the proportions of the areas Rc, Rd, Re, Rj, and Rk are substituted for R1, R2, ..., Rn. Also, equation 6 is applied to all small regions 60c, 60d, 60e, 60j, and 60k that the bucket 13 has passed through during the leveling operation. In other words, in modified example 2, of the soil in each of the small areas 60c, 60d, 60e, 60j, and 60k, only the portion Rc, Rd, Re, Rj, and Rk of the area that passed through bucket 13 is considered to have been leveled, while the other portions are considered not to have been leveled. W'=(W1×R1+W2×R2+...+Wn×Rn) / n...(Formula 5) Wn'=Wn×(1-Rn)+W'×Rn (Formula 6)

[0078] According to variations 1 and 2, the weight balance of the soil in the loading area 60 after the leveling operation can be recognized by the operator with even greater accuracy.

[0079] [Other variations] The loading area identification process does not limit the input to the four corners A, B, C, and D of the rectangular loading area 60 using the bucket 13. As another example, the input may specify two diagonal vertices A and D (or vertices B and C) of the rectangular loading area 60. Furthermore, the loading area 60 is not limited to a rectangle, but may be any shape that represents a closed area, such as a triangle or a circle (perfect circle, ellipse). In addition, the input to the loading area identification process using the bucket 13 is set appropriately according to the shape of the loading area (for example, three vertices for a triangle, or the center and one point on the circumference for a perfect circle). Moreover, the loading area identification process may have a function to reset the vertex positions stored in memory 32 if an operator notices an alignment error.

[0080] Furthermore, the size and shape of the small regions 60a to 60l are not limited to the examples of the embodiments described above. As another example, the small regions 60a to 60l may be smaller than the area of ​​the bucket 13 as viewed from above.

[0081] Furthermore, if the weight addition unit 55 determines that a dumping operation has been performed with the bucket 13 overlapping multiple small areas (for example, small areas 60c, 60d), it may distribute and add the weight W of the soil contained in the bucket 13 to the multiple small areas 60c, 60d that the bucket 13 overlaps. The method of distribution is not particularly limited, but for example, the weight W may be divided equally, or it may be distributed proportionally considering the proportion of the overlapping area of ​​the bucket 13.

[0082] The embodiments described above are illustrative for explaining the present invention and are not intended to limit the scope of the invention to those embodiments only. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the invention. [Explanation of Symbols]

[0083] 1: Hydraulic excavator 2: Lower running body 3: Upper rotating body 4: Crawler 5: Driving motor 6: Swivel motor 7: Swivel Frame 8: Cab 9: Counterweight 10: Front work machine 11: Boom 12: Arm 13: Bucket 14: Boom Cylinder 14a: Cylinder tube 14b: Cylinder rod 15: Arm Cylinder 16: Bucket Cylinder 30: Controller 31: CPU 32: Memory 33: Operating device 34: Vertex selection switch 35a, 35b: GPS antenna 36b, 36r: Pressure sensors 37, 38, 39: Angle sensors 40: Hydraulic Circuit 41: Display 51: Attitude detection unit 52: Weight measurement unit 53: Bucket position identification unit 54:Loading area identification part 55: Weight addition section 56: Leveling area identification unit 57: Weight update section 60:Loading area 60a~60l: Small area 61: Arrow 62, 63: Landmark X1, X2, X3: Center of rotation

Claims

1. Lower running body and An upper slewing body is rotatably supported on the lower traveling body, A working device comprising a boom rotatably supported on the upper rotating body, an arm rotatably supported at the tip of the boom, a bucket rotatably supported at the tip of the arm, and a hydraulic cylinder for rotating the boom, A posture sensor for detecting the posture of the work device, A pressure sensor for detecting the pressure of the hydraulic fluid in the hydraulic cylinder, A display that shows information, A hydraulic excavator comprising a controller that measures the weight of the load contained in the bucket based on the posture of the work device detected by the posture sensor and the pressure of the hydraulic fluid detected by the pressure sensor, The hydraulic excavator is equipped with a position sensor that detects its position, The aforementioned controller, Based on the detection results of the position sensor and the attitude sensor, the position of the bucket is determined. The loading area, as indicated by the identified bucket location, is divided into multiple sub-regions. When it is determined that the loaded material has been discharged from the bucket within the loading area, the measured weight of the loaded material is added to the small area that overlaps with the identified bucket location. A hydraulic excavator characterized by displaying the weight of the load in each of the multiple sub-regions on the display.

2. In the hydraulic excavator according to claim 1, The aforementioned controller, When it is determined that a leveling operation has been performed to level the loads placed in multiple of the aforementioned small areas using the bucket, the multiple aforementioned small areas that the bucket passed through during the leveling operation are identified. A hydraulic excavator characterized by averaging the weight of the loads in a plurality of specified small areas and redistributing them to those small areas.

3. In the hydraulic excavator according to claim 2, The controller is characterized in that, among the multiple small regions that the bucket has passed through in the leveling operation, it averages the weight of only the small regions where the proportion of the area passed through by the bucket is equal to or greater than a threshold, and redistributes the weight to those small regions.

4. In the hydraulic excavator according to claim 2, The controller is characterized by redistributing the weight of the multiple small areas that the bucket has passed through in the leveling operation, weighted and averaged according to the proportion of the area that the bucket has passed through, to the small areas.

5. In the hydraulic excavator according to claim 2, The hydraulic excavator is characterized in that the controller determines that the leveling operation is being performed when the bucket is moving within the loading area while the measured weight is a negative value.

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