Shovel

Abstract

The invention provides a shovel which enables the weight of an object moving to a predetermined place to be calculated more accurately. A shovel (100) for moving an object to a predetermined location by repeating a series of operations including an excavating operation and a dumping operation is provided with: a lower traveling body (1); an upper rotating body (3) rotatably mounted on the lower traveling body (1); an attachment device (AT) attached to the upper rotating body (3); a sensor attached to the upper rotating body (3); and a controller (30) that calculates, on the basis of the output of the sensor, a digging reaction force generated by the digging operation and a digging weight, which is the weight of an object taken into the bucket (6) and moved to a prescribed location. The controller (30) sets, on the basis of the relationship between the excavation reaction force calculated during one or more first excavation operations and the excavation weight, a target value relating to the excavation reaction force during one or more second excavation operations performed thereafter.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2023-218209 filed on December 25, 2023. The entire contents of the Japanese application are incorporated herein by reference.

[0002] The present invention relates to an excavator. Background Art

[0003] Conventionally, there has been known an excavator that calculates the weight of sand and soil loaded into a bucket lifted into the air based on the measured value of a boom bottom pressure sensor (see Patent Document 1).

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-165260

[0005] However, in the case where the detection value of the boom bottom pressure sensor deviates due to external interference generated in a state where the bucket is lifted into the air, the above-described excavator may not be able to appropriately calculate the weight of an object such as sand and soil loaded into the bucket. At this time, the excavator may not be able to accurately calculate the weight of an object that has been moved (loaded) to a specified place such as the carriage of a dump truck by an excavation attachment.

[0006] Therefore, it is desired to be able to calculate more accurately the weight of an object that has been moved to a specified place. Summary of the Invention

[0007] An excavator according to an embodiment of the present invention moves an object to a specified place by repeating a series of operations including an excavation operation and a dumping operation, and the excavator includes: a lower traveling body; an upper revolving body rotatably mounted on the lower traveling body; an attachment mounted on the upper revolving body; a sensor mounted on the upper revolving body; and a control device that calculates, based on an output of the sensor, a digging reaction force generated by the excavation operation and the weight of an object taken into the bucket and moved to the place, that is, a digging weight, and the control device sets a target value related to the digging reaction force at one or more subsequent second excavation operations based on a relationship between the digging reaction force and the digging weight calculated at one or more first excavation operations.

[0008] Advantages of the Invention

[0009] The above-described excavator can calculate more accurately the weight of an object that has been moved to a specified place. Brief Description of the Drawings

[0010] Figure 1 is a side view of the excavator.

[0011] Figure 2 is a diagram schematically showing a structural example of a control system of the excavator.

[0012] Figure 3 It is a diagram schematically showing a structural example of the hydraulic system of an excavator.

[0013] Figure 4A It is a diagram of a part of the hydraulic system related to the operation of the arm cylinder.

[0014] Figure 4B It is a diagram of a part of the hydraulic system related to the operation of the boom cylinder.

[0015] Figure 4C It is a diagram of a part of the hydraulic system related to the operation of the bucket cylinder.

[0016] Figure 4D It is a diagram of a part of the hydraulic system related to the operation of the swing hydraulic motor.

[0017] Figure 4E It is a diagram of a part of the hydraulic system related to the operation of the left travel hydraulic motor.

[0018] Figure 4F It is a diagram of a part of the hydraulic system related to the operation of the right travel hydraulic motor.

[0019] Figure 5 It is a diagram explaining the process of the loading operation of the excavator.

[0020] Figure 6 It is a flowchart showing an example of the process of the setting process.

[0021] Figure 7 It is a flowchart showing an example of the support process flow.

[0022] Figure 8 It is a flowchart showing another example of the process of the setting process.

[0023] Figure 9 It is a diagram of an excavator for an excavation trench.

[0024] Figure 10 It is a flowchart showing yet another example of the process of the setting process.

[0025] Figure 11 It is a top view of an excavator loading sand into a dump truck.

[0026] In the figure: 1 - Lower traveling body, 2 - Slewing mechanism, 2A - Slewing hydraulic motor, 2M - Traveling hydraulic motor, 2ML - Left traveling hydraulic motor, 2MR - Right traveling hydraulic motor, 3 - Upper slewing body, 4 - Boom, 5 - Arm, 6 - Bucket, 7 - Boom cylinder, 8 - Arm cylinder, 9 - Bucket cylinder, 10 - Cab, 11 - Engine, 13 - Regulator, 14 - Main pump, 15 - Pilot pump, 17 - Control valve unit, 18L - Left throttle, 18R - Right throttle, 19L - Left control pressure sensor, 19R - Right control pressure sensor, 26 - Operating device, 26D - Traveling operating device, 26DL - Left traveling lever, 26DR - Right traveling lever, 26L - Left operating lever, 26R - Right operating lever, 28 - Discharge pressure sensor, 29, 29DL, 29DR, 29LA, 29LB, 29RA, 29RB - Operating sensors, 30 - Controller, 31, 31AL to 31FL, 31AR to 31FR - Solenoid valves, 40 - Display device, 42 - Input device, 42a - Mode switch, 43 - Sound output device, 47 - Storage device, 50 - Equipment guiding section, 51 - Position calculation section, 52 - Distance calculation section, 53 - Information transmission section, 54 - Automatic control section, 55 - Excavation reaction force calculation section, 56 - Target setting section, 57 - Excavation support section, 100 - Excavator, 171 to 176 - Control valves, 200 - Dump truck, AT - Attachment, CB - Carriage, DP - Depth, DS, DS1, DS2, DS3 - Sandy soil, GR - Trough, LS - Sandy soil, Q1 - Position measuring device, S1 - Boom angle sensor, S2 - Arm angle sensor, S3 - Bucket angle sensor, S4 - Machine body tilt sensor, S5 - Slewing state sensor, S6 - Imaging device, S6B, S6F, S6L, S6R - Cameras, S7B - Boom bottom pressure sensor, S7R - Boom rod pressure sensor, S8B - Arm bottom pressure sensor, S8R - Arm rod pressure sensor, S9B - Bucket bottom pressure sensor, S9R - Bucket rod pressure sensor, SW, SW1, SW2 - Switches, T1 - Communication device. Detailed implementation manners

[0027] Hereinafter, with reference to the drawings, the excavator 100 according to the embodiments of the present invention will be described. First, with reference to Figure 1 , an overview of the excavator 100 will be described. Figure 1 FIG. is a side view of the excavator 100.

[0028] The excavator 100 includes a lower traveling body 1, an upper slewing body 3 that is rotatably mounted on the lower traveling body 1 via a slewing mechanism 2, a boom 4, an arm 5, and a bucket 6 that constitute an example of an attachment AT, i.e., an excavation attachment, and a cab 10.

[0029] The lower walking body 1 is driven by a walking hydraulic motor 2M (reference Figure 2 ) is hydraulically driven to make the shovel 100 travel. The travel hydraulic motor 2M includes a left travel hydraulic motor 2ML and a right travel hydraulic motor 2MR. That is, the left travel hydraulic motor 2ML and the right travel hydraulic motor 2MR drive the lower travel body 1 (crawler) as a driven part.

[0030] The upper rotating body 3 is driven by a rotating hydraulic motor 2A (reference Figure 2 ) is driven to rotate relative to the lower traveling body 1. That is, the rotary hydraulic motor 2A is a rotary driving part that drives the upper rotary body 3 as a driven part, and can change the direction of the upper rotary body 3.

[0031] In addition, the upper revolving body 3 may be electrically driven by a revolving electric motor as an electric actuator instead of the revolving hydraulic motor 2A. That is, like the revolving hydraulic motor 2A, the revolving electric motor is a revolving driving part that drives the upper revolving body 3 as a driven part, and can change the direction of the upper revolving body 3.

[0032] The boom 4 is rotatably mounted at the front center of the upper slewing body 3, a dipper arm 5 is rotatably mounted at the front end of the boom 4, and a bucket 6 as an end attachment is rotatably mounted at the front end of the dipper arm 5. The boom 4, dipper arm 5 and bucket 6 are hydraulically driven by a boom cylinder 7, an dipper arm cylinder 8 and a bucket cylinder 9 as hydraulic actuators, respectively.

[0033] The bucket 6 is an example of an end attachment, and other end attachments such as a slope bucket, a dredging bucket, or a crusher may be mounted on the tip of the arm 5 instead of the bucket 6 depending on the work content.

[0034] The cab 10 is a cabin in which an operator rides, and is provided on the front left side of the upper revolving body 3 .

[0035] Then, except Figure 1 In addition, refer to Figure 2 , the specific structure of the excavator 100 is described. Figure 2 1 is a diagram schematically showing a configuration example of a control system of the shovel 100. Figure 2 In the figure, the mechanical power transmission line, the working oil line, the pilot line and the electrical signal line are represented by double lines, solid lines, dashed lines and dotted lines, respectively.

[0036] The drive system of the excavator 100 includes an engine 11, a regulator 13, a main pump 14, and a control valve unit 17. Moreover, the hydraulic drive system of the excavator 100 includes hydraulic actuators such as a travel hydraulic motor 2M, a swing hydraulic motor 2A, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 that hydraulically drive the lower travel body 1, the upper swing body 3, the boom 4, the arm 5, and the bucket 6, respectively.

[0037] The engine 11 is a power source in the hydraulic drive system and is mounted, for example, at the rear of the upper swing body 3. Specifically, the engine 11 rotates constantly at a preset target speed under the direct or indirect control of the controller 30 and drives the main pump 14 and the pilot pump 15. The engine 11 is, for example, a diesel engine.

[0038] The regulator 13 controls the discharge volume of the main pump 14. For example, the regulator 13 adjusts the angle (deflection angle) of the swash plate of the main pump 14 according to a control instruction from the controller 30. The regulator 13 includes, for example, a left regulator 13L and a right regulator 13R (refer to Figure 3 ).

[0039] The main pump 14 is mounted, for example, at the rear of the upper swing body 3 and supplies working oil to the control valve unit 17 through a working oil pipeline. The main pump 14 is driven by the engine 11. The main pump 14 is, for example, a variable-capacity hydraulic pump. Under the control of the controller 30, the stroke length of the piston is adjusted by regulating the deflection angle of the swash plate by the regulator 13, and the discharge flow rate (displacement) is controlled. The main pump 14 includes, for example, a left main pump 14L and a right main pump 14R (refer to Figure 3 ).

[0040] The control valve unit 17 is, for example, mounted at the center of the upper swing body 3 and is a hydraulic control device that controls the hydraulic drive system according to the operation of the operator on the operating device 26. The control valve unit 17 is connected to the main pump 14 through a working oil pipeline and selectively supplies the working oil supplied from the main pump 14 to a plurality of hydraulic actuators (travel hydraulic motor 2M, swing hydraulic motor 2A, boom cylinder 7, arm cylinder 8, and bucket cylinder 9) according to the operation state of the operating device 26. Specifically, the control valve unit 17 includes control valves 171 to 176 that control the flow rate and flow direction of the working oil supplied from the main pump 14 to each hydraulic actuator. More specifically, the control valve 171 corresponds to the left travel hydraulic motor 2ML, the control valve 172 corresponds to the right travel hydraulic motor 2MR, and the control valve 173 corresponds to the swing hydraulic motor 2A. Moreover, the control valve 174 corresponds to the bucket cylinder 9, the control valve 175 corresponds to the boom cylinder 7, and the control valve 176 corresponds to the arm cylinder 8. The control valve 175 includes, for example, a control valve 175L and a control valve 175R, and the control valve 176 includes, for example, a control valve 176L and 176R (refer to Figure 3 ).

[0041] The operating system of the excavator 100 includes a pilot pump 15 and an operating device 26. Moreover, the operating system of the excavator 100 includes a solenoid valve 31 as a structure related to the equipment control function based on the controller 30.

[0042] The pilot pump 15 is mounted, for example, at the rear of the upper swing body 3 and supplies pilot pressure to the pilot ports of the control valves 171 to 176 via pilot pipes. The pilot pump 15 is, for example, a fixed-displacement hydraulic pump and is driven by the engine 11.

[0043] The operating device 26 is provided near the driver's seat in the cab 10 and is an operation input mechanism for an operator to perform operations of various motion components (the lower traveling body 1, the upper swing body 3, the boom 4, the arm 5, the bucket 6, etc.). In other words, the operating device 26 is an operation input mechanism for an operator to perform operations of hydraulic actuators (the traveling hydraulic motor 2M, the swing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, etc.) that drive the respective motion components. Pilot pressures corresponding to the operation contents (operation direction and operation amount) of the operating device 26 are input to the pilot ports of the control valves 171 to 176. In the illustrated example, the operating device 26 includes a lever device for operating the upper swing body 3 (swing hydraulic motor 2A) and the arm 5 (arm cylinder 8), i.e., a left operating lever 26L (refer to Figure 4A ), a lever device for operating the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9), i.e., a right operating lever 26R (refer to Figure 4B ), and a traveling operation device 26D for operating the crawlers of the lower traveling body 1 (traveling hydraulic motor 2M) (refer to Figure 4E ). The traveling operation device 26D includes a left traveling lever 26DL for operating the left crawler (left traveling hydraulic motor 2ML) (refer to Figure 4E ), and a right traveling lever 26DR for operating the right crawler (right traveling hydraulic motor 2MR) (refer to Figure 4F ). The traveling operation device 26D may include a left traveling pedal for operating the left crawler (left traveling hydraulic motor 2ML) and a right traveling pedal for operating the right crawler (right traveling hydraulic motor 2MR).

[0044] In the illustrated example, the operating device 26 is an electric operating device that outputs an electric signal. The electric signal from the operating device 26 is input to the controller 30. The controller 30 controls the pilot pressure applied to the pilot ports of the control valves 171 to 176 based on the input electric signal, thereby realizing the operations of various hydraulic actuators corresponding to the operation content of the operating device 26. Specifically, solenoid valves 31 that operate according to an electric signal from the controller 30 are arranged between the pilot pump 15 and the pilot ports of the control valves 171 to 176 respectively. Moreover, when the operating device 26 is operated, the controller 30 controls the solenoid valves 31 through an electric signal corresponding to the operation amount (for example, lever operation amount) to increase or decrease the pilot pressure, thereby enabling each of the control valves 171 to 176 to operate corresponding to the operation content of the operating device 26. In addition, the control valves 171 to 176 may be solenoid-operated spool valves that are driven according to an instruction from the controller 30.

[0045] The control system of the excavator 100 includes a controller 30, a discharge pressure sensor 28, an operation sensor 29, solenoid valves 31, a display device 40, an input device 42, a sound output device 43, a storage device 47, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a body tilt sensor S4, a swing state sensor S5, a camera device S6, a positioning device Q1, and a communication device T1.

[0046] The controller 30 (an example of a control device) is configured to be provided in the cab 10 and perform drive control of the excavator 100. The functions of the controller 30 can be realized by any hardware, software, or a combination thereof. In the illustrated example, the controller 30 is mainly configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile auxiliary storage device, various input / output interfaces, etc. The controller 30 realizes various functions, for example, by executing various programs stored in the ROM or the non-volatile auxiliary storage device on the CPU.

[0047] In the illustrated example, the controller 30 sets a target rotational speed according to a work mode or the like preset by a prescribed operation by an operator or the like, and performs drive control to make the engine 11 rotate at a constant speed. The controller 30 can output a control instruction to the regulator 13 as needed to change the discharge amount of the main pump 14.

[0048] The controller 30 can be configured to perform control related to a device guidance function for guiding an operator to manually operate the excavator 100 through the operating device 26. Further, the controller 30 can be configured to perform control related to a device control function for automatically assisting the operator to manually operate the excavator 100 through the operating device 26. At this time, the controller 30 can include a device guidance unit 50 as a functional unit related to the device guidance function and the device control function.

[0049] In addition, a part of the functions of the controller 30 can be implemented by other controllers (control devices). That is, the functions of the controller 30 can also be implemented in a distributed manner by multiple controllers. For example, the device guidance function and the device control function can also be implemented by dedicated controllers (control devices).

[0050] The discharge pressure sensor 28 detects the discharge pressure of the main pump 14. A detection signal corresponding to the discharge pressure detected by the discharge pressure sensor 28 is input to the controller 30. The discharge pressure sensor 28 includes, for example, a left discharge pressure sensor 28L and a right discharge pressure sensor 28R (refer to Figure 3 ).

[0051] The operation sensor 29 detects the operation content (operation direction and operation amount) of the operating device 26. The detection signal of the operation sensor 29 is input to the controller 30. The operation sensor 29 includes, for example, an operation sensor 29LA that detects the operation content in the front-rear direction (arm operation direction) of the left operation lever 26L (refer to Figure 4A ), an operation sensor 29RA that detects the operation content in the front-rear direction (boom operation direction) of the right operation lever 26R (refer to Figure 4B ), an operation sensor 29RB that detects the operation content in the left-right direction (bucket operation direction) of the right operation lever 26R (refer to Figure 4C ), an operation sensor 29LB that detects the operation content in the left-right direction (slewing operation direction) of the left operation lever 26L (refer to Figure 4D ), an operation sensor 29DL that detects the operation content of the left travel lever 26DL (refer to Figure 4E ), and an operation sensor 29DR that detects the operation content of the right travel lever 26DR (refer to Figure 4F ).

[0052] In the illustrated example, the operation sensor 29 is an inclination sensor that can detect the operation amount (tilt amount) or tilt direction of the operating device 26, but it can also be any sensor such as an encoder or a potentiometer.

[0053] The solenoid valve 31 is configured to be provided in the pilot pipe line connecting the pilot pump 15 and the pilot ports of the control valves 171 to 176, and capable of changing its flow path area (the cross-sectional area through which the working oil can flow). The solenoid valve 31 operates according to the control command input from the controller 30. Thus, even when the operating device 26 is not operated by the operator, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the pilot ports of the control valves 171 to 176 via the solenoid valve 31. In the illustrated example, as Figures 4A - 4F shown, the solenoid valve 31 includes solenoid valves 31AL to 31FL and solenoid valves 31AR to 31FR.

[0054] The display device 40 is provided at a place where it is easily visually recognizable by the operator sitting on the driver's seat in the cab 10, and displays various information under the control of the controller 30. The display device 40 can be connected to the controller 30 via the in-vehicle communication network, or can be connected to the controller 30 via a one-to-one dedicated line.

[0055] The input device 42 is provided within the reach of the hand of the operator sitting on the driver's seat in the cab 10, receives various operation inputs from the operator, and outputs a signal corresponding to the operation input to the controller 30. The input device 42 is, for example, a touch panel installed on the screen of the display device 40 that displays various information, a rotary switch provided at the front end of the lever portion of the lever device, a push button switch provided around the display device 40, a lever, a toggle switch, or a rotary dial, etc. A signal corresponding to the operation of the input device 42 is input to the controller 30.

[0056] In addition, the input device 42 has a mode switch 42a. The mode switch 42a is a switch for switching the operation mode of the excavator 100. The operation mode refers to the operation category of the excavator 100, and includes, for example, a crane mode and a normal mode, etc. In addition, the mode switch 42a can be a software switch displayed on the screen of the display device 40, can be a hardware switch provided around the display device 40, or can be a switch provided at other positions in the cab 10.

[0057] The sound output device 43 is provided, for example, in the cab 10, is connected to the controller 30, and outputs sound under the control of the controller 30. The sound output device 43 is, for example, a speaker or a buzzer, etc. The sound output device 43 outputs various information in an audible manner according to the sound output command from the controller 30.

[0058] The storage device 47 is provided, for example, in the cab 10 and stores various information under the control of the controller 30. The storage device 47 is, for example, a non-volatile storage medium such as a semiconductor memory. The storage device 47 can store the information output by various devices during the operation of the excavator 100, and can also store the information acquired via various devices before the start of the operation of the excavator 100. The storage device 47 can store, for example, data related to the target point acquired via the communication device T1 or the like, or set via the input device 42 or the like. The target point is, for example, a point on the target construction surface. The data related to the target point can be set (saved) by the operator of the excavator 100 or by a construction manager or the like.

[0059] The boom angle sensor S1 is installed on the boom 4 and detects the rotation angle of the boom 4 relative to the upper swing body 3 (hereinafter, "boom angle"). For example, when viewed from the side, it is the angle formed by the straight line connecting the two end points (center points of the connecting pins) of the boom 4 and the rotation plane of the upper swing body 3 (a plane perpendicular to the rotation axis). The boom angle sensor S1 is, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an IMU (Inertial Measurement Unit), or a combination thereof. And the boom angle sensor S1 can be composed of a potentiometer using a variable resistor, a cylinder sensor that detects the stroke amount of the hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, etc. The same applies to the arm angle sensor S2 and the bucket angle sensor S3. The detection signal corresponding to the boom angle based on the boom angle sensor S1 is input to the controller 30.

[0060] The arm angle sensor S2 is installed on the arm 5 and detects the rotation angle of the arm 5 relative to the boom 4 (hereinafter, "arm angle"). For example, it detects the angle formed by the straight line connecting the two end points (center points of the connecting pins) of the arm 5 and the straight line connecting the two end points (center points of the connecting pins) of the boom 4 when viewed from the side. The detection signal corresponding to the arm angle based on the arm angle sensor S2 is input to the controller 30.

[0061] The bucket angle sensor S3 is installed on the bucket 6 and detects the rotation angle of the bucket 6 relative to the arm 5 (hereinafter, "bucket angle"). For example, it detects the angle formed by the straight line connecting the fulcrum (center point of the connecting pin) and the front end (bucket tip) of the bucket 6 and the straight line connecting the two end points (center points of the connecting pins) of the arm 5 when viewed from the side. The detection signal corresponding to the bucket angle based on the bucket angle sensor S3 is input to the controller 30. Additionally, the bucket angle sensor S3 can be omitted. In this case, the controller 30 can infer the bucket angle based on the output of the operation sensor 29RB.

[0062] The machine body tilt sensor S4 detects the tilt state of the machine body (the upper slewing body 3 or the lower traveling body 1) relative to the horizontal plane. The machine body tilt sensor S4 is installed, for example, on the upper slewing body 3, and detects the tilt angles (hereinafter, "front-back tilt angle" and "left-right tilt angle") of the excavator 100 (i.e., the upper slewing body 3) around two axes in the front-back direction and the left-right direction. The machine body tilt sensor S4 is, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an IMU, or a combination thereof. The detection signals corresponding to the tilt angles (front-back tilt angle and left-right tilt angle) based on the machine body tilt sensor S4 are input to the controller 30.

[0063] The slewing state sensor S5 outputs information related to the slewing state of the upper slewing body 3. The slewing state sensor S5 detects, for example, the slewing angular velocity of the upper slewing body 3. The slewing state sensor S5 may also detect the slewing angle. The slewing state sensor S5 is, for example, a gyro sensor, a resolver, or a rotary encoder. The detection signal corresponding to the slewing angular velocity of the upper slewing body 3 based on the slewing state sensor S5 is input to the controller 30.

[0064] The imaging device S6 as a space recognition device captures the surroundings of the excavator 100. In the illustrated example, the imaging device S6 includes a camera S6F that captures the front of the excavator 100, a camera S6L that captures the left side of the excavator 100, a camera S6R that captures the right side of the excavator 100, and a camera S6B that captures the rear of the excavator 100. In addition, the imaging device S6 can be directly communicatively connected to the controller 30.

[0065] In the illustrated example, the camera S6F is installed on the ceiling of the cab 10, that is, inside the cab 10. The camera S6F can also be installed outside the cab 10, such as on the roof of the cab 10 or the side of the boom 4. The camera S6L is installed at the left end of the upper surface of the upper slewing body 3, the camera S6R is installed at the right end of the upper surface of the upper slewing body 3, and the camera S6B is installed at the rear end of the upper surface of the upper slewing body 3.

[0066] The imaging device S6 (the camera S6F, the camera S6B, the camera S6L, and the camera S6R) is respectively, for example, a monocular wide-angle camera with a wide viewing angle. The imaging device S6 can respectively be a stereo camera or a distance image camera. The captured images based on each imaging device S6 are input to the controller 30 via the display device 40.

[0067] The imaging device S6 as a space recognition device can function as an object detection device. At this time, the imaging device S6 can detect objects existing around the excavator 100. Among the objects to be detected, for example, it can include people, animals, vehicles, construction machinery, buildings, and pits, etc. The imaging device S6 as an object detection device can also calculate the distance from the imaging device S6 or the excavator 100 to the identified object. The imaging device S6 as an object detection device can be a stereo camera or a distance image sensor, etc. Specifically, the imaging device S6 is a monocular camera having an imaging element such as a CCD or a CMOS, and outputs the captured image to the display device 40.

[0068] In the excavator 100, in addition to the imaging device S6, other object detection devices such as an ultrasonic sensor, a millimeter wave radar, a LIDAR, and an infrared sensor can be provided as space recognition devices. The millimeter wave radar, ultrasonic sensor, or lidar, etc. as space recognition devices can emit a plurality of signals (such as laser) toward the object and receive the reflected signal, and thereby detect the distance and direction of the object based on the reflected signal.

[0069] A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are installed on the boom cylinder 7. A stick rod pressure sensor S8R and a stick bottom pressure sensor S8B are installed on the stick cylinder 8. A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B are installed on the bucket cylinder 9. At least one of the boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the stick rod pressure sensor S8R, the stick bottom pressure sensor S8B, the bucket rod pressure sensor S9R, and the bucket bottom pressure sensor S9B is also collectively referred to as a "cylinder pressure sensor".

[0070] The boom rod pressure sensor S7R detects the pressure of the rod side oil chamber of the boom cylinder 7 (hereinafter, referred to as "boom rod pressure"). The boom bottom pressure sensor S7B detects the pressure of the bottom side oil chamber of the boom cylinder 7 (hereinafter, referred to as "boom bottom pressure"). The stick rod pressure sensor S8R detects the pressure of the rod side oil chamber of the stick cylinder 8 (hereinafter, referred to as "stick rod pressure"). The stick bottom pressure sensor S8B detects the pressure of the bottom side oil chamber of the stick cylinder 8 (hereinafter, referred to as "stick bottom pressure"). The bucket rod pressure sensor S9R detects the pressure of the rod side oil chamber of the bucket cylinder 9 (hereinafter, referred to as "bucket rod pressure"). The bucket bottom pressure sensor S9B detects the pressure of the bottom side oil chamber of the bucket cylinder 9 (hereinafter, referred to as "bucket bottom pressure").

[0071] The positioning device Q1 is configured to measure the position of the upper rotating body 3. In the illustrated example, the positioning device Q1 is a GNSS (Global Navigation Satellite System) compass that detects the position and orientation of the upper rotating body 3, and a detection signal corresponding to the position and orientation of the upper rotating body 3 is input to the controller 30. Additionally, the orientation of the upper rotating body 3 can also be detected by other devices such as an azimuth sensor installed on the upper rotating body 3.

[0072] The communication device T1 is configured to communicate with an external device through any communication network including a mobile communication network, a satellite communication network, or the Internet, etc. Specifically, the communication device T1 can be composed of a mobile communication module corresponding to mobile communication standards such as LTE (Long Term Evolution), 4G (4th Generation), or 5G (5th Generation), or a satellite communication module for connecting to a satellite communication network, etc.

[0073] The equipment guidance unit 50 is configured to execute an equipment guidance function. In the illustrated example, the equipment guidance unit 50 transmits operation information such as the distance between a target point and a control point (e.g., the working part of the termination accessory) to the operator through the display device 40 or the sound output device 43, etc. Data related to the target point is pre-stored in the storage device 47. The data related to the target point is represented in a reference coordinate system. The reference coordinate system is, for example, the World Geodetic System. The World Geodetic System is a three-dimensional orthogonal XYZ coordinate system with the origin placed at the center of gravity of the Earth, the X-axis set as the direction of the intersection of the Greenwich meridian and the equator, the Y-axis set as the direction of 90 degrees east longitude, and the Z-axis set as the direction of the North Pole. The operator can set the relative position relationship between the reference point determined arbitrarily at the construction site and the target point based on the input device 42. The working part of the termination accessory is, for example, the tip of the bucket 6 or the back of the bucket 6, etc. The equipment guidance unit 50 notifies the operator of the operation information through the display device 40 or the sound output device 43, etc., and guides the operator to operate the excavator 100 through the operation device 26.

[0074] Furthermore, the equipment guidance unit 50 can be configured to execute an equipment control function. For example, when the operator operates manually, the equipment guidance unit 50 can cause at least one of the swing hydraulic motor 2A, the travel hydraulic motor 2M, the boom 4, the arm 5, and the bucket 6 to act automatically so that the target point coincides with the control point (a point on the working part of the termination accessory).

[0075] In the illustrated example, the equipment guidance unit 50 obtains information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the body tilt sensor S4, the slewing state sensor S5, the imaging device S6, the positioning device Q1, the communication device T1, the input device 42, and the like. Moreover, the equipment guidance unit 50 calculates the distance between the target point and the control point based on the acquired information, and notifies the operator of the magnitude of the distance between the target point and the control point through the sound from the sound output device 43 and the image displayed on the display device 40, or automatically controls the operation of the actuator so that the control point coincides with the target point. The equipment guidance unit 50 includes a position calculation unit 51, a distance calculation unit 52, an information transmission unit 53, an automatic control unit 54, an excavation reaction force calculation unit 55, a target setting unit 56, and an excavation support unit 57 as functional components related to the equipment guidance function and the equipment control function.

[0076] The position calculation unit 51 calculates the position of a specified positioning object. For example, the position calculation unit 51 calculates the coordinates of the control point in the reference coordinate system. Specifically, the position calculation unit 51 calculates the coordinates of the control point based on the traveling distance of the lower traveling body 1, the slewing angle of the upper slewing body 3, and the respective rotation angles (boom angle, arm angle, and bucket angle) of the boom 4, the arm 5, and the bucket 6.

[0077] The distance calculation unit 52 is configured to calculate the distance between two positioning objects. In the illustrated example, the distance calculation unit 52 calculates the distance between the control point and the target point. For example, the distance calculation unit 52 calculates the distance between the control point on the tip of the bucket 6 and the point on the target construction surface.

[0078] The information transmission unit 53 transmits (notifies) various information to the operator of the excavator 100 through a notification mechanism such as the display device 40 or the sound output device 43. The information transmission unit 53 can notify the operator of the magnitude of various distances calculated by the distance calculation unit 52. For example, the information transmission unit 53 can transmit the magnitude of the distance between the control point and the target point to the operator using at least one of the visual information based on the display device 40 and the auditory information based on the sound output device 43.

[0079] Specifically, the information transmission unit 53 can use the intermittent sound of the sound output device 43 to transmit the magnitude of the distance between the control point and the target point to the operator. At this time, the information transmission unit 53 can perform the following operations: the smaller the distance becomes, the shorter the interval of the intermittent sound; the larger the distance becomes, the longer the interval of the intermittent sound. Also, the information transmission unit 53 can use continuous sound and can also indicate the difference in the magnitude of the distance while changing the pitch or intensity of the sound, etc. And when the control point at the front end of the bucket 6 is at a position lower than the target construction surface, that is, when it exceeds the target construction surface, the information transmission unit 53 can issue an alarm through the sound output device 43. This alarm is, for example, a continuous sound significantly louder than the intermittent sound.

[0080] Also, the information transmission unit 53 can display the magnitude of the distance between the control point and the target point, etc. as operation information on the display device 40. Under the control of the controller 30, the display device 40 can display the operation information received from the information transmission unit 53 together with the image data received from the imaging device S6. The information transmission unit 53 can use an image of an analog meter or an image of a bar graph indicator, etc. to transmit the magnitude of this distance to the operator.

[0081] The automatic control unit 54 automatically supports the operator's manual operation of the excavator 100 through the operation device 26 by automatically operating the actuator. Specifically, the automatic control unit 54 can separately and automatically adjust the pilot pressure acting on the pilot port of the control valve corresponding to each of the plurality of hydraulic actuators. Thereby, the automatic control unit 54 can make each hydraulic actuator operate automatically. The control related to the equipment control function of the automatic control unit 54 can be executed, for example, when a specified switch included in the input device 42 is pressed. The specified switch is, for example, an equipment control switch (hereinafter, "MC (Machine Control) switch") and can be configured as a rotary switch at the front end of the grip portion of the operation device 26 (for example, the boom operation lever, which is a lever device used in the operation of the boom 5). The following describes the equipment control function executed when the MC switch is pressed.

[0082] For example, when the MC switch or the like is pressed, in order to support the excavation operation, the automatic control unit 54 automatically expands and contracts at least one of the boom cylinder 7 and the bucket cylinder 9 corresponding to the movement of the boom cylinder 8 corresponding to the operation of the boom operation lever. Specifically, when the operator manually performs the closing operation of the boom 5 (hereinafter, "boom closing operation"), the automatic control unit 54 automatically expands and contracts at least one of the boom cylinder 7 and the bucket cylinder 9 so that the target point on the target construction surface coincides with the control point on the working part such as the tip or the back surface of the bucket 6. At this time, for example, the operator can make the tip of the bucket 6 coincide with the target construction surface while closing the boom 5 only by operating the boom operation lever in the boom closing direction.

[0083] The digging reaction force calculation unit 55 is configured to derive the digging reaction force. The digging reaction force is the reaction force of the digging force, and is a force having the same magnitude as the digging force and in the opposite direction to the digging force. In the illustrated example, the digging reaction force calculation unit 55 derives the digging reaction force based on the posture of the digging attachment and the load acting on the digging attachment. The posture of the digging attachment is detected by a posture sensor. The posture sensor includes at least one of an arm angle sensor S1, a boom angle sensor S2, and a bucket angle sensor S3. The load acting on the digging attachment is detected by a cylinder pressure sensor. The cylinder pressure sensor includes at least one of a boom rod pressure sensor S7R, a boom bottom pressure sensor S7B, a boom rod pressure sensor S8R, a boom bottom pressure sensor S8B, a bucket rod pressure sensor S9R, and a bucket bottom pressure sensor S9B.

[0084] Specifically, the digging reaction force calculation unit 55 repeatedly derives the digging reaction force at a prescribed operation cycle using a prescribed calculation formula. The digging reaction force calculation unit 55 derives the digging reaction force as follows: the deeper the digging depth, that is, the greater the vertical distance between the ground contact surface of the excavator 100 and the tip of the bucket 6, the greater the digging reaction force becomes. And, the digging reaction force calculation unit 55 derives the digging reaction force as follows: the greater the depth of the tip of the bucket 6 with respect to the ground to be dug, that is, the ground penetration depth, the greater the digging reaction force becomes. And, the digging reaction force calculation unit 55 can derive the digging reaction force in consideration of sand characteristics such as sand density. The sand characteristics can be a value input by the operator through the input device 42 or the like, or can be a value automatically calculated based on the outputs of various sensors such as the cylinder pressure sensor. And, the digging reaction force calculation unit 55 can be configured to calculate at least one of the horizontal component and the vertical component of the digging reaction force.

[0085] The target setting unit 56 is configured to set a target value related to the digging operation. In the illustrated example, the target setting unit 56 is configured to determine whether a prescribed digging operation suitable for calculating the target value has been performed based on information related to the digging operation of the attachment device AT on the work object (ground to be dug) in the work site, and to set the target value based on the digging reaction force calculated during the digging operation determined to be the prescribed digging operation. In addition, the target setting unit 56 can determine that the prescribed digging operation has been performed when only a prescribed number of prescribed digging operations have been performed. That is, even if the prescribed digging operation has been performed, the target setting unit 56 can determine that the prescribed digging operation has not been performed if the number of times is less than the prescribed number. And, hereinafter, the digging operation performed before setting the target value is sometimes referred to as the "first digging operation", and the digging operation performed after setting the target value is sometimes referred to as the "second digging operation".

[0086] Information related to the excavation operation is, for example, information related to the excavation volume such as the amount of sandy soil taken into the bucket 6. The amount of sandy soil taken into the bucket 6 is typically the volume of the sandy soil contained in the bucket 6 in the air after the excavation operation and before the dumping operation. The volume of the sandy soil can be calculated, for example, based on an image of the bucket 6 in the air captured by the camera S6F. Alternatively, the amount of sandy soil taken into the bucket 6 can be inferred based on an image of the ground (the ground above the bucket 6 underground) captured by the camera S6F. Specifically, the amount of sandy soil can be inferred based on the state of the ground bulged due to the movement of the bucket 6 in the latter half of the excavation operation (the movement of the bucket 6 lifted from underground by the boom raising operation). Alternatively, the amount of sandy soil taken into the bucket 6 can be inferred based on the ground image before the excavation operation and the ground image after the excavation operation captured by the camera S6F. Specifically, the amount of sandy soil can be inferred based on the change in the ground shape before and after the excavation operation. Alternatively, the amount of sandy soil taken into the bucket 6 can be the weight of the sandy soil contained in the bucket 6. The weight of the sandy soil can be calculated, for example, based on the output of the posture sensor and the output of the cylinder pressure sensor.

[0087] When the amount of sandy soil taken into the bucket 6 is obtained, when it can be recognized that the bucket 6 is filled with sandy soil, or when it can be recognized that the amount of sandy soil taken into the bucket 6 reaches 80% or 90% of the accommodation capacity of the bucket 6, etc., when it can be recognized that the amount of sandy soil taken into the bucket 6 (volume or weight) is more than the specified amount (specified volume or specified weight), the target setting unit 56 determines that a specified excavation operation suitable for calculating the target value has been performed.

[0088] In addition, the information related to the excavation operation can be information input by the operator of the excavator 100. The information input by the operator of the excavator 100 is, for example, information for transmitting the situation where the operator determines that a specified excavation operation has been performed to the controller 30. The operator of the excavator 100 can transmit the situation where the operator determines that a specified excavation operation has been performed to the controller 30, for example, by pressing a specified button which is one of the input devices 42.

[0089] The specified excavation operation is an excavation operation suitable for calculating the target value, for example, an excavation operation when the bucket 6 can be filled with sandy soil, or an excavation operation when the amount of sandy soil can be taken into 80% or 90% of the accommodation capacity of the bucket 6, etc.

[0090] The target value is a value used to reproduce a specified excavation operation, for example, the maximum value of the excavation reaction force (maximum excavation reaction force) that is calculated and recorded when a specified excavation operation is performed. Additionally, it can also be a value calculated based on the maximum value of the excavation reaction force. For example, the target value can be a value obtained by adding a specified value to the maximum value of the excavation reaction force, or a value obtained by subtracting a specified value from the maximum value of the excavation reaction force. Also, the target value can be the maximum value of the horizontal component of the excavation reaction force or the maximum value of the vertical component of the excavation reaction force. Moreover, the target value can be a value calculated based on the change in the excavation reaction force that is calculated and recorded when a specified excavation operation is performed.

[0091] Furthermore, the target value can be the average value of the maximum values of the excavation reaction forces in each excavation operation of multiple specified excavation operations, that is, the average value of multiple maximum excavation reaction forces (maximum average excavation reaction force). Also, the target value can be the median value or the mode value, etc., of multiple maximum excavation reaction forces.

[0092] Moreover, the target setting unit 56 can set the excavation reaction force corresponding to the desired excavation amount as the target value based on the correlation between the maximum value of the excavation reaction force and the excavation amount in each excavation operation of one or more excavation operations. At this time, the desired excavation amount, such as 80% or 90% of the capacity of the bucket 6, can be a pre-set excavation amount or an excavation amount input through the input device 42. Additionally, the correlation can be stored as a calculation formula such as a linear equation or a quadratic equation, or can be stored as a reference table.

[0093] The excavation support unit 57 is configured to support the excavation operation performed by the operator of the excavator 100. In the illustrated example, the excavation support unit 57 is configured to support each excavation operation after the target value is set by the target setting unit 56. Specifically, when the value of the excavation reaction force repeatedly calculated during the excavation operation reaches the target value, the excavation support unit 57 notifies the operator of the excavator 100 of the situation where the value of the excavation reaction force has reached the target value through a notification mechanism such as the display device 40 or the sound output device 43. At this time, the operator performs a boom raising operation to lift at least a part of the bucket 6 located underground into the air, thereby enabling the excavation operation to end with the bucket 6 filled with sand and soil.

[0094] When the excavation reaction force reaches the target value, the excavation support unit 57 can cause one or more actuators to operate automatically. Causing the actuators to operate automatically means causing the actuators to operate regardless of the operation of the operating device 26. In the illustrated example, the actuators are at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9. In the illustrated example, when the excavation reaction force reaches the target value, the excavation support unit 57 automatically extends the boom cylinder 7 to raise the boom 4, and lifts the bucket 6 at least partially located underground into the air, so that the excavation operation can end with the bucket 6 filled with sand. Also, when the excavation reaction force reaches the target value, even when the operator operates the operating device 26, the excavation support unit 57 can stop the excavation operation of the excavation attachment. After the excavation operation stops, the operator performs a boom raising operation to raise the boom 4, and lifts the bucket 6 at least partially located underground into the air, so that the excavation operation can end with the bucket 6 filled with sand.

[0095] The excavation support unit 57 can be configured to support the excavation operation performed by the operator of the excavator 100 even when the value of the excavation reaction force repeatedly calculated during the excavation operation does not reach the target value after the target value is set by the target setting unit 56. For example, the excavation support unit 57 can cause one or more actuators to operate automatically so that the working part of the end attachment (the tip of the bucket 6) moves linearly until the value of the excavation reaction force reaches the target value. Specifically, the excavation support unit 57 can cause at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 to operate automatically so that the tip of the bucket 6 moves linearly along the ground contact surface, the horizontal plane, or the target construction surface, etc. during the excavation operation. At this time, the operator of the excavator 100 can, for example, only perform an arm closing operation to move the tip of the bucket 6 located underground linearly along the ground contact surface, the horizontal plane, or the target construction surface, etc. until the value of the excavation reaction force reaches the target value, and when the value of the excavation reaction force reaches the target value, can lift the bucket 6 at least partially located underground into the air and end the excavation operation with the bucket 6 filled with sand. This structure is effective, for example, when excavating a groove with a constant depth.

[0096] Next, referring to Figure 3 , the hydraulic system of the excavator 100 will be described. Figure 3 is a diagram schematically showing a structural example of the hydraulic system of the excavator 100. In addition, in Figure 3 , similar to the case of Figure 2 etc., the mechanical power transmission line, the working oil line, the pilot line, and the electrical signal line are represented by double lines, solid lines, dotted lines, and dashed lines, respectively.

[0097] The hydraulic system circulates the working oil from the left main pump 14L driven by the engine 11 to the working oil tank via the left center bypass oil passage C1L and the left parallel oil passage C2L, and circulates the working oil from the right main pump 14R driven by the engine 11 to the working oil tank via the right center bypass oil passage C1R and the right parallel oil passage C2R.

[0098] The left center bypass oil passage C1L starts from the left main pump 14L and sequentially passes through the control valves 171, 173, 175L, and 176L arranged in the control valve unit 17, and reaches the working oil tank.

[0099] The right center bypass oil passage C1R starts from the right main pump 14R and sequentially passes through the control valves 172, 174, 175R, and 176R arranged in the control valve unit 17, and reaches the working oil tank.

[0100] The control valve 171 is a spool valve that supplies the working oil discharged from the left main pump 14L to the left travel hydraulic motor 2ML and discharges the working oil discharged from the left travel hydraulic motor 2ML to the working oil tank.

[0101] The control valve 172 is a spool valve that supplies the working oil discharged from the right main pump 14R to the right travel hydraulic motor 2MR and discharges the working oil discharged from the right travel hydraulic motor 2MR to the working oil tank.

[0102] The control valve 173 is a spool valve that supplies the working oil discharged from the left main pump 14L to the swing hydraulic motor 2A and discharges the working oil discharged from the swing hydraulic motor 2A to the working oil tank.

[0103] The control valve 174 is a spool valve that supplies the working oil discharged from the right main pump 14R to the bucket cylinder 9 and discharges the working oil in the bucket cylinder 9 to the working oil tank.

[0104] The control valve 175 includes the control valve 175L and the control valve 175R. The control valve 175L is a spool valve that supplies the working oil discharged from the left main pump 14L to the boom cylinder 7 and discharges the working oil in the boom cylinder 7 to the working oil tank. The control valve 175R is a spool valve that supplies the working oil discharged from the right main pump 14R to the boom cylinder 7 and discharges the working oil in the boom cylinder 7 to the working oil tank.

[0105] The control valve 176 includes the control valve 176L and the control valve 176R. The control valve 176L is a spool valve that supplies the working oil discharged from the left main pump 14L to the arm cylinder 8 and discharges the working oil in the arm cylinder 8 to the working oil tank. The control valve 176R is a spool valve that supplies the working oil discharged from the right main pump 14R to the arm cylinder 8 and discharges the working oil in the arm cylinder 8 to the working oil tank.

[0106] The control valves 171 to 176 respectively adjust the flow rate of the working oil supplied to the hydraulic actuator or switch the flow direction according to the pilot pressure acting on the pilot ports.

[0107] The left parallel oil passage C2L is configured to be arranged in parallel with the left center bypass oil passage C1L and can supply the working oil discharged from the left main pump 14L to the control valves 173, the control valve 175L, and the control valve 176L respectively. Thus, when the flow of the working oil through the left center bypass oil passage C1L is restricted or blocked by any one of the control valves 171, the control valve 173, or the control valve 175L, the left parallel oil passage C2L can supply the working oil to the control valve further downstream.

[0108] The right parallel oil passage C2R is configured to be arranged in parallel with the right center bypass oil passage C1R and can supply the working oil discharged from the right main pump 14R to the control valves 174, the control valve 175R, and the control valve 176R respectively. Thus, when the flow of the working oil through the right center bypass oil passage C1R is restricted or blocked by any one of the control valves 172, the control valve 174, or the control valve 175R, the right parallel oil passage C2R can supply the working oil to the control valve further downstream.

[0109] The left regulator 13L is configured to be able to adjust the discharge amount of the left main pump 14L by adjusting the deflection angle of the swash plate of the left main pump 14L under the control of the controller 30. The right regulator 13R is configured to be able to adjust the discharge amount of the right main pump 14R by adjusting the deflection angle of the swash plate of the right main pump 14R under the control of the controller 30.

[0110] The left discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L, and a detection signal corresponding to the detected discharge pressure is input to the controller 30. The same applies to the right discharge pressure sensor 28R. Thus, the controller 30 can control the left regulator 13L according to the discharge pressure of the left main pump 14L and can control the right regulator 13R according to the discharge pressure of the right main pump 14R.

[0111] In the left center bypass oil passage C1L, a left throttle 18L is provided between the control valve 176L located at the most downstream and the working oil tank. Thus, the flow of the working oil discharged from the left main pump 14L is restricted by the left throttle 18L. Moreover, the left throttle 18L generates a left control pressure for controlling the left regulator 13L. In the right center bypass oil passage C1R, a right throttle 18R is provided between the control valve 176R located at the most downstream and the working oil tank. Thus, the flow of the working oil discharged from the right main pump 14R is restricted by the right throttle 18R. Moreover, the right throttle 18R generates a right control pressure for controlling the right regulator 13R.

[0112] The left control pressure sensor 19L detects the left control pressure, and a detection signal corresponding to the detected left control pressure is input to the controller 30. The right control pressure sensor 19R detects the right control pressure, and a detection signal corresponding to the detected right control pressure is input to the controller 30.

[0113] The controller 30 can control the left regulator 13L according to the discharge pressure of the left main pump 14L detected by the left discharge pressure sensor 28L, and adjust the discharge amount of the left main pump 14L. For example, the controller 30 can control the left regulator 13L according to the increase in the discharge pressure of the left main pump 14L, and adjust the swash plate deflection angle of the left main pump 14L, thereby reducing the discharge amount of the left main pump 14L. The same applies to the right regulator 13R. Thus, the controller 30 can perform the total horsepower control of the main pump 14 so that the absorbed horsepower of the main pump 14 represented by the product of the discharge pressure and the discharge amount does not exceed the output horsepower of the engine 11.

[0114] Moreover, the controller 30 can control the left regulator 13L according to the left control pressure detected by the left control pressure sensor 19L, thereby adjusting the discharge amount of the left main pump 14L. For example, the controller 30 reduces the discharge amount of the left main pump 14L more when the left control pressure is larger, and increases the discharge amount of the left main pump 14L more when the left control pressure is smaller. The same applies to the discharge amount of the right main pump 14R.

[0115] Specifically, in the standby state where none of the hydraulic actuators in the excavator 100 are operated ( Figure 3 the state shown), the working oil discharged from the left main pump 14L reaches the left throttle 18L through the left center bypass oil passage C1L. Moreover, the flow of the working oil discharged from the left main pump 14L increases the left control pressure generated upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the allowable minimum discharge amount, and suppresses the pressure loss (suction loss) when the working oil discharged from the left main pump 14L passes through the left center bypass oil passage C1L. The same applies to the pressure loss (suction loss) when the working oil discharged from the right main pump 14R passes through the right center bypass oil passage C1R.

[0116] On the other hand, when any one of the hydraulic actuators is operated by the operation device 26, the working oil discharged from the left main pump 14L flows into the hydraulic actuator to be operated through the control valve corresponding to the hydraulic actuator to be operated. Moreover, the flow of the working oil discharged from the left main pump 14L reduces or eliminates the amount reaching the left throttle 18L, and reduces the left control pressure generated upstream of the left throttle 18L. As a result, the controller 30 can increase the discharge amount of the left main pump 14L, circulate sufficient working oil in the hydraulic actuator to be operated, and reliably drive the hydraulic actuator to be operated. The same applies to the working oil discharged from the right main pump 14R.

[0117] Next, referring to Figures 4A - 4F , the structure of the controller 30 for operating the actuator will be described. Figures 4A - 4F This is a diagram showing a part of the hydraulic system. Specifically, Figure 4A this is a diagram showing a part of the hydraulic system related to the operation of the arm cylinder 8, Figure 4B this is a diagram showing a part of the hydraulic system related to the operation of the boom cylinder 7. Figure 4C This is a diagram showing a part of the hydraulic system related to the operation of the bucket cylinder 9, Figure 4D this is a diagram showing a part of the hydraulic system related to the operation of the swing hydraulic motor 2A. Figure 4E This is a diagram showing a part of the hydraulic system related to the operation of the left travel hydraulic motor 2ML, Figure 4F this is a diagram showing a part of the hydraulic system related to the operation of the right travel hydraulic motor 2MR.

[0118] As Figures 4A - 4F shown, the hydraulic system includes a solenoid valve 31. The solenoid valve 31 includes solenoid valves 31AL to 31FL and solenoid valves 31AR to 31FR.

[0119] The solenoid valve 31 is configured to be disposed in a pipeline connecting the pilot pump 15 and the pilot port of the corresponding control valve in the control valve unit 17, and the flow path area of this pipeline can be changed by changing the opening area. In the present embodiment, the solenoid valve 31 is an electromagnetic proportional valve and operates according to a control command output by the controller 30. Therefore, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the solenoid valve 31, either according to the operation of the operator on the operating device 26 or independently of the operation of the operator on the operating device 26. Moreover, the controller 30 can make the pilot pressure generated by the solenoid valve 31 act on the pilot port of the corresponding control valve.

[0120] According to this structure, in addition to the case where a specific operating device 26 is operated, the controller 30 can operate the hydraulic actuator corresponding to the specific operating device 26 even when the specific operating device 26 is not operated. Also, even when a specific operating device 26 is operated, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operating device 26.

[0121] For example, as Figure 4AAs shown, the left joystick 26L is used to operate the arm 5. Specifically, the left joystick 26L uses the pilot oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot ports of the control valve 176. More specifically, when the left joystick 26L is operated in the arm closing direction (rear direction), a pilot pressure corresponding to the operation amount is applied to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. And when the left joystick 26L is operated in the arm opening direction (front direction), a pilot pressure corresponding to the operation amount is applied to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

[0122] A switch SW is provided in the operating device 26. In this embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is an MC switch (push-button switch) provided at the front end of the left joystick 26L. The operator can operate the left joystick 26L while pressing the switch SW1. The switch SW1 can be provided on the right joystick 26R or at other positions within the cab 10. The switch SW2 is an MC switch (push-button switch) provided at the front end of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 can be provided on the right travel lever 26DR or at other positions within the cab 10.

[0123] The operation sensor 29LA detects the operation content of the operator on the left joystick 26L in the front-rear direction and outputs the detected value to the controller 30.

[0124] The solenoid valve 31AL operates according to the control command (current command) output by the controller 30. Moreover, the pilot pressure generated by the pilot oil is adjusted, and the pilot oil is introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL. The solenoid valve 31AR operates according to the control command (current command) output by the controller 30. Moreover, the pilot pressure generated by the pilot oil is adjusted, and the pilot oil is introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR. The solenoid valve 31AL can adjust the pilot pressure so that the control valves 176L and 176R can stop at any valve position. Similarly, the solenoid valve 31AR can adjust the pilot pressure so that the control valves 176L and 176R can stop at any valve position.

[0125] According to this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL according to the operator's boom closing operation. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL regardless of the operator's boom closing operation. That is, the controller 30 can close the boom 5 according to the operator's boom closing operation or regardless of the operator's boom closing operation. Thus, the solenoid valve 31AL functions as a "boom solenoid valve" or a "boom closing solenoid valve".

[0126] Also, the controller 30 supplies the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR according to the operator's boom opening operation. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR regardless of the operator's boom opening operation. That is, the controller 30 can open the boom 5 according to the operator's boom opening operation or regardless of the operator's boom opening operation. Thus, the solenoid valve 31AR functions as a "boom solenoid valve" or a "boom opening solenoid valve".

[0127] Also, according to this structure, even when the operator performs a boom closing operation, the controller 30 can reduce the pilot pressure acting on the closing side pilot ports of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) as needed, and forcibly stop the closing action of the boom 5. The same applies to the case of forcibly stopping the opening action of the boom 5 when the operator performs a boom opening operation.

[0128] Alternatively, even when the operator performs a boom closing operation, the controller 30 can control the solenoid valve 31AR as needed to increase the pilot pressure acting on the opening side pilot ports of the control valve 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) located on the side opposite to the closing side pilot ports of the control valve 176, and forcibly return the control valve 176 to the neutral position, thereby forcibly stopping the closing action of the boom 5. The same applies to the case of forcibly stopping the opening action of the boom 5 when the operator performs a boom opening operation.

[0129] And, omitting reference to the following Figures 4B - 4FThe same applies to the case where the operation of the boom 4 is forcibly stopped when the operator performs a boom raising operation or a boom lowering operation, the case where the operation of the bucket 6 is forcibly stopped when the operator performs a bucket closing operation or a bucket opening operation, and the case where the swing operation of the upper swing body 3 is forcibly stopped when the operator performs a swing operation. Also, the same applies to the case where the traveling operation of the lower traveling body 1 is forcibly stopped when the operator performs a traveling operation.

[0130] Further, the controller 30 may also be configured to apply a minute pilot pressure to both pilot ports of the control valve 176 from before the stick operation (stick closing operation and stick opening operation) is performed, in order to improve the responsiveness of the stick operation. The same applies to other operations such as the boom operation (boom raising operation and boom lowering operation). That is, the controller 30 can improve the responsiveness of the hydraulic actuator by using more pilot oil.

[0131] Further, as Figure 4B shown, the right operation lever 26R is used to operate the boom 4. Specifically, the right operation lever 26R causes a pilot pressure corresponding to the operation in the front-rear direction to act on the pilot port of the control valve 175 by using the pilot oil discharged from the pilot pump 15. More specifically, when the right operation lever 26R is operated in the boom raising direction (rear direction), a pilot pressure corresponding to the operation amount acts on the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. Further, when the right operation lever 26R is operated in the boom lowering direction (front direction), a pilot pressure corresponding to the operation amount acts on the right pilot port of the control valve 175R.

[0132] The operation sensor 29RA detects the operation content of the operator on the right operation lever 26R in the front-rear direction, and outputs the detected value to the controller 30.

[0133] The solenoid valve 31BL operates according to the control command (current command) output from the controller 30. Further, the pilot pressure generated by the pilot oil is adjusted, and the pilot oil is introduced from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL. The solenoid valve 31BR operates according to the control command (current command) output from the controller 30. Further, the pilot pressure generated by the pilot oil is adjusted, and the pilot oil is introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR. The solenoid valve 31BL can adjust the pilot pressure so that the control valve 175L and the control valve 175R can stop at an arbitrary valve position. Further, the solenoid valve 31BR can adjust the pilot pressure so that the control valve 175R can stop at an arbitrary valve position.

[0134] According to this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL according to the boom raising operation of the operator. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL regardless of the boom raising operation of the operator. That is, the controller 30 can raise the boom 4 according to the boom raising operation of the operator or regardless of the boom raising operation of the operator. Thus, the solenoid valve 31BL functions as a "boom solenoid valve" or a "boom raising solenoid valve".

[0135] Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR according to the boom lowering operation of the operator. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR regardless of the boom lowering operation of the operator. That is, the controller 30 can lower the boom 4 according to the boom lowering operation of the operator or regardless of the boom lowering operation of the operator. Thus, the solenoid valve 31BR functions as a "boom solenoid valve" or a "boom lowering solenoid valve".

[0136] Also, as Figure 4C shown, the right operation lever 26R is used to operate the bucket 6. Specifically, the right operation lever 26R causes a pilot pressure corresponding to the operation in the left - right direction to act on the pilot port of the control valve 174 by using the pilot oil discharged from the pilot pump 15. More specifically, when the right operation lever 26R is operated in the bucket closing direction (left direction), a pilot pressure corresponding to the operation amount acts on the left pilot port of the control valve 174. Also, when the right operation lever 26R is operated in the bucket opening direction (right direction), a pilot pressure corresponding to the operation amount acts on the right pilot port of the control valve 174.

[0137] The operation sensor 29RB detects the operation content of the operator on the right operation lever 26R in the left - right direction and outputs the detected value to the controller 30. Additionally, when the bucket angle sensor S3 is omitted, the controller 30 can infer the bucket angle based on the output of the operation sensor 29RB.

[0138] The solenoid valve 31CL operates according to the control command (current command) output by the controller 30. Moreover, the pilot pressure generated by the pilot oil is adjusted, and this pilot oil is introduced from the pilot pump 15 into the left pilot port of the control valve 174 via the solenoid valve 31CL. The solenoid valve 31CR operates according to the control command (current command) output by the controller 30. Moreover, the pilot pressure generated by the pilot oil is adjusted, and this pilot oil is introduced from the pilot pump 15 into the right pilot port of the control valve 174 via the solenoid valve 31CR. The solenoid valve 31CL can adjust the pilot pressure so that the control valve 174 can stop at any valve position. Similarly, the solenoid valve 31CR can adjust the pilot pressure so that the control valve 174 can stop at any valve position.

[0139] According to this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL according to the operator's bucket closing operation. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL regardless of the operator's bucket closing operation. That is, the controller 30 can close the bucket 6 according to the operator's bucket closing operation or regardless of the operator's bucket closing operation. Thus, the solenoid valve 31CL functions as a "bucket solenoid valve" or a "bucket closing solenoid valve".

[0140] And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR according to the operator's bucket opening operation. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR regardless of the operator's bucket opening operation. That is, the controller 30 can open the bucket 6 according to the operator's bucket opening operation or regardless of the operator's bucket opening operation. Thus, the solenoid valve 31CR functions as a "bucket solenoid valve" or a "bucket opening solenoid valve".

[0141] And, as Figure 4D shown, the left operation lever 26L is used to operate the slewing mechanism 2. Specifically, the left operation lever 26L uses the pilot oil discharged from the pilot pump 15 to make the pilot pressure corresponding to the operation in the left - right direction act on the pilot port of the control valve 173. More specifically, when the left operation lever 26L is operated in the left slewing direction (left direction), the pilot pressure corresponding to the operation amount acts on the left pilot port of the control valve 173. And when the left operation lever 26L is operated in the right slewing direction (right direction), the pilot pressure corresponding to the operation amount acts on the right pilot port of the control valve 173.

[0142] The operation sensor 29LB detects the operation content of the operator on the left joystick 26L in the left-right direction, and outputs the detected value to the controller 30.

[0143] The solenoid valve 31DL operates according to the control command (current command) output from the controller 30. Moreover, the pilot pressure generated by the pilot oil can be adjusted, and the pilot oil is introduced from the pilot pump 15 into the left pilot port of the control valve 173 via the solenoid valve 31DL. The solenoid valve 31DR operates according to the control command (current command) output from the controller 30. Moreover, the pilot pressure generated by the pilot oil is adjusted, and the pilot oil is introduced from the pilot pump 15 into the right pilot port of the control valve 173 via the solenoid valve 31DR. The solenoid valve 31DL can adjust the pilot pressure so that the control valve 173 can stop at any valve position. Similarly, the solenoid valve 31DR can adjust the pilot pressure so that the control valve 173 can stop at any valve position.

[0144] According to this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL according to the left rotation operation of the operator. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL regardless of the left rotation operation of the operator. That is, the controller 30 can make the slewing mechanism 2 rotate left according to the left rotation operation of the operator or regardless of the left rotation operation of the operator. Thus, the solenoid valve 31DL functions as a "slewing solenoid valve" or a "left rotation solenoid valve".

[0145] And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR according to the right rotation operation of the operator. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR regardless of the right rotation operation of the operator. That is, the controller 30 can make the slewing mechanism 2 rotate right according to the right rotation operation of the operator or regardless of the right rotation operation of the operator. Thus, the solenoid valve 31DR functions as a "slewing solenoid valve" or a "right rotation solenoid valve".

[0146] And, as Figure 4EAs shown, the left travel lever 26DL is used to operate the left crawler belt 1CL. Specifically, the left travel lever 26DL uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-back direction to the pilot port of the control valve 171. More specifically, when the left travel lever 26DL is operated in the forward direction (front direction), a pilot pressure corresponding to the operation amount is applied to the left pilot port of the control valve 171. And when the left travel lever 26DL is operated in the backward direction (rear direction), a pilot pressure corresponding to the operation amount is applied to the right pilot port of the control valve 171.

[0147] The operation sensor 29DL electrically detects the operation content of the operator on the left travel lever 26DL in the front-back direction and outputs the detected value to the controller 30.

[0148] The solenoid valve 31EL operates according to the current command output by the controller 30. And the solenoid valve 31EL adjusts the pilot pressure generated by the pilot oil that is introduced from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL. The solenoid valve 31ER operates according to the current command output by the controller 30. And the solenoid valve 31ER adjusts the pilot pressure generated by the pilot oil that is introduced from the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER. The solenoid valves 31EL and 31ER can adjust the pilot pressure so that the control valve 171 can stop at any valve position.

[0149] According to this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL regardless of the operator's left forward operation. That is, the left crawler belt 1CL can be made to move forward. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER regardless of the operator's left backward operation. That is, the left crawler belt 1CL can be made to move backward. Thus, the solenoid valve 31EL functions as a "left travel solenoid valve" or a "left forward solenoid valve", and the solenoid valve 31ER functions as a "left travel solenoid valve" or a "left backward solenoid valve".

[0150] And, as Figure 4FAs shown, the right travel lever 26DR is used to operate the right crawler belt 1CR. Specifically, the right travel lever 26DR uses the pilot oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 172. More specifically, when the right travel lever 26DR is operated in the forward direction (front direction), a pilot pressure corresponding to the operation amount is applied to the right pilot port of the control valve 172. And when the right travel lever 26DR is operated in the backward direction (rear direction), a pilot pressure corresponding to the operation amount is applied to the left pilot port of the control valve 172.

[0151] The operation sensor 29DR electrically detects the operation content of the operator on the right travel lever 26DR in the front-rear direction and outputs the detected value to the controller 30.

[0152] The solenoid valve 31FL operates according to the current command output by the controller 30. And the solenoid valve 31FL adjusts the pilot pressure generated by the pilot oil, and this pilot oil is introduced from the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FL. The solenoid valve 31FR operates according to the current command output by the controller 30. And the solenoid valve 31FR adjusts the pilot pressure generated by the pilot oil, and this pilot oil is introduced from the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FR. The solenoid valves 31FL and 31FR can adjust the pilot pressure so that the control valve 172 can stop at an arbitrary valve position.

[0153] According to this structure, the controller 30 can supply the pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FL regardless of the operator's right forward operation. That is, the right crawler belt 1CR can be made to move forward. And the controller 30 can supply the pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FR regardless of the operator's right backward operation. That is, the right crawler belt 1CR can be made to move backward. Thus, the solenoid valve 31FL functions as a "right travel solenoid valve" or a "right forward solenoid valve", and the solenoid valve 31FR functions as a "right travel solenoid valve" or a "right backward solenoid valve".

[0154] And the excavator 100 may also be provided with a structure for automatically operating the bucket tilting mechanism. At this time, the hydraulic system part related to the bucket tilting cylinder constituting the bucket tilting mechanism may also be configured in the same way as the hydraulic system part related to the operation of the boom cylinder 7 and the like.

[0155] Further, as a mode of the operating device 26, a description related to an electric operating lever is given, but instead of the electric operating lever, a hydraulic operating lever may be employed. In this case, the operation amount of the hydraulic operating lever can be detected in the form of pressure by a pressure sensor and input to the controller 30. Also, a solenoid valve may be disposed between the operating device 26 serving as the hydraulic operating lever and the pilot ports of the respective control valves. The solenoid valve is configured to operate according to an electric signal from the controller 30. According to this configuration, if a manual operation using the operating device 26 serving as the hydraulic operating lever is performed, the operating device 26 can move the respective control valves by increasing or decreasing the pilot pressure according to the operation amount. Also, the respective control valves may be constituted by solenoid slide valves. In this case, the solenoid slide valves operate according to an electric signal from the controller 30 corresponding to the operation amount of the electric operating lever.

[0156] Next, with reference to Figure 5 , the process of the loading operation of the excavator 100 will be described. Figure 5 is a diagram for explaining the process of the loading operation of the excavator 100.

[0157] Figure 5 (A) to Figure 5 (D) of Figure 5 show the state of performing the excavation operation. In addition, the period during which the excavation operation is performed is referred to as the excavation operation period. Also, the excavation operation is divided into Figure 5 (A) of Figure 5 and the first half of the excavation operation shown in Figure 5 (B) of

[0158] As shown in Figure 5 (A) of Figure 5 , the operator of the excavator 100 moves the front end of the bucket 6 so that the front end of the bucket 6 is at a desired height position relative to the excavation target (sand in this example), and closes the arm 5 from the state where the arm 5 is opened as shown in Figure 5 (A) of

[0159] to the state where the arm 5 is substantially perpendicular to the ground as shown in Figure 5 (B) of Figure 5 . By this action, sand at a certain depth is excavated, and the sand is scraped together until the arm 5 is substantially perpendicular to the ground surface. The above action is referred to as the first half of the excavation operation, and this period is referred to as the first half period of the excavation operation. Figure 5to the position shown in (D) of the above. The above action is called the latter half of the digging action, and this period is called the latter half period of the digging action. Figure 5 The action of (C) can be a combined action of the arm 5 and the bucket 6, or a combined action of the boom 4, the arm 5 and the bucket 6.

[0160] Next, the operator, while keeping the upper edge of the bucket 6 substantially horizontal, as Figure 5 shown in (E), raises the boom 4 until the bottom of the bucket 6 is at a desired height above the ground. The desired height is, for example, a height above the height of the rear door of the dump truck. After or simultaneously with this action, the operator rotates the upper revolving body 3 as indicated by the arrow to move the bucket 6 to the position for unloading (tipping).

[0161] If the operator completes the boom raising and rotating action, then as Figure 5 shown in (F), the operator opens the arm 5 and the bucket 6 to unload (tip) the soil in the bucket 6 onto the carriage of the dump truck or the ground, etc. In this unloading action (tipping action), the operator can unload by only opening the bucket 6, or can unload while lowering the boom 4 and opening the arm 5 and the bucket 6.

[0162] If the operator completes the tipping action, then as Figure 5 shown in (G), the operator rotates the upper revolving body 3 as indicated by the arrow to move the bucket 6 directly above the digging position. Then, as Figure 5 shown in (A), the operator lowers the bucket 6 to the desired height and performs the digging action again. In addition, the operator can lower the boom 4 simultaneously with the rotation so that the bucket 6 descends from the object to be dug to the desired height.

[0163] In this way, the controller 30 advances the loading operation of the excavator 100 while repeating the cycle (series of actions) composed of the "digging action", the "boom raising and rotating action", the "tipping action" and the "boom lowering and rotating action".

[0164] Next, with reference to Figure 6 , an example of the process of setting the target value for the controller 30 (hereinafter, referred to as "setting process".) will be described. Figure 6 is a flowchart showing an example of the process of the setting process. In the illustrated example, the target setting unit 56 of the controller 30 executes this setting process each time the digging action is completed until the target value is set. Specifically, the target setting unit 56 determines whether the digging action is completed based on the outputs of the posture sensor, the cylinder pressure sensor, etc. And when the target setting unit 56 determines that the digging action is completed, it executes this setting process.

[0165] First, the target setting unit 56 determines whether a specified excavation operation has been performed (step ST1). In the illustrated example, the target setting unit 56 determines whether the amount of sand and soil taken into the bucket 6 is more than a specified amount based on an image of the bucket 6 lifted into the air after the excavation operation captured by the camera S6F. Moreover, when the target setting unit 56 can determine that the amount of sand and soil taken into the bucket 6 is more than the specified amount, it determines that the specified excavation operation has been performed. For example, when the target setting unit 56 can determine that the bucket 6 is full of sand and soil, it determines that the specified excavation operation has been performed. On the other hand, when the target setting unit 56 cannot determine that the amount of sand and soil taken into the bucket 6 is more than the specified amount, that is, when it can determine that the bucket 6 is not full of sand and soil, it determines that the specified excavation operation has not been performed. In addition, even when the target setting unit 56 can determine that the bucket 6 is full of sand and soil, if it determines that the amount of sand and soil spilled from the bucket 6 when the bucket 6 is lifted is more than the specified amount, it can also determine that the specified excavation operation has not been performed.

[0166] Moreover, the target setting unit 56 can determine that the specified excavation operation has been performed when a specified button is pressed. The specified button is a button pressed by the operator when the operator visually observes the inside of the bucket 6 lifted into the air after the excavation operation and determines that the bucket 6 is full of sand and soil. In addition, the operator can also view the image captured by the camera S6F to determine whether the bucket 6 is full of sand and soil. At this time, the image captured by the camera S6F can be displayed on the display device 40.

[0167] Moreover, in the case where it is determined that the specified excavation operation has not been performed (the "no" in step ST1), the target setting unit 56 ends the current setting process without setting a target value.

[0168] On the other hand, in the case where it is determined that the specified excavation operation has been performed (the "yes" in step ST1), the target setting unit 56 sets a target value (step ST2). In the illustrated example, the target setting unit 56 sets the maximum value of the excavation reaction force calculated during the execution of the excavation operation determined to be the specified excavation operation as the target value. In addition, the target setting unit 56 can also set the maximum value of the horizontal component or the vertical component of the excavation reaction force calculated during the execution of the excavation operation determined to be the specified excavation operation as the target value. At this time, this target value is used to compare with the horizontal component or the vertical component of the excavation reaction force calculated during the subsequent excavation operation.

[0169] Next, Figure 7 an example of the process flow of the processing (hereinafter referred to as "support processing") in which the controller 30 supports the excavation operation will be described. Figure 7It is a flowchart showing an example of the support processing flow. In the illustrated example, during the excavation operation, the excavation support unit 57 of the controller 30 repeatedly executes this support processing at a prescribed control cycle. Specifically, the excavation support unit 57 determines whether to perform the excavation operation based on the outputs from the posture sensor, the cylinder pressure sensor, etc. More specifically, the excavation support unit 57 determines that the excavation operation has started when the excavation reaction force repeatedly calculated by the excavation reaction force calculation unit 55 at a prescribed control cycle exceeds a prescribed start determination value. And, after determining that the excavation operation has started, the excavation support unit 57 determines that the excavation operation has ended when the excavation reaction force repeatedly calculated by the excavation reaction force calculation unit 55 at a prescribed control cycle is lower than a prescribed end determination value. The start determination value and the end determination value are respectively values determined based on the posture of the attachment device. Moreover, the excavation support unit 57 repeatedly executes this support processing during the period from determining that the excavation operation has started to determining that the excavation operation has ended. In addition, the excavation support unit 57 can also make various determinations based on the magnitude of the horizontal component or the vertical component of the excavation reaction force repeatedly calculated by the excavation reaction force calculation unit 55 at a prescribed control cycle. At this time, the start determination value and the end determination value are respectively values corresponding to the magnitude of the horizontal component or the vertical component of the excavation reaction force.

[0170] First, the excavation support unit 57 determines whether the excavation reaction force has reached the target value (step ST11). In the illustrated example, the excavation support unit 57 determines whether the excavation reaction force calculated by the excavation reaction force calculation unit 55 has reached the target value set by the target setting unit 56. When the target setting unit 56 has not set the target value, that is, when the target value maintains the initial value (the maximum value that the excavation reaction force can take), the excavation support unit 57 determines that the excavation reaction force has not reached the target value. And, the excavation support unit 57 can be configured not to execute the support processing until the target value is set.

[0171] When it is determined that the excavation reaction force has reached the target value (Yes in step ST11), the excavation support unit 57 executes the excavation support function (step ST12). In the illustrated example, the excavation support function is a function of notifying the operator of the excavator 100 that the excavation reaction force has reached the target value. Specifically, the excavation support unit 57 outputs a control command to the display device 40 so that the display device 40 displays image information notifying that the excavation reaction force has reached the target value, or outputs a control command to the sound output device 43 so that the sound output device 43 outputs sound information notifying that the excavation reaction force has reached the target value. The information notifying that the excavation reaction force has reached the target value can be, for example, information indicating the start of the boom raising operation. By receiving such information, the operator of the excavator 100 can start the boom raising operation at an appropriate timing. As a result, the operator can, for example, achieve a state where the bucket 6 is fully loaded with sand at the end of each excavation operation. That is, the controller 30 can achieve an appropriate excavation amount through each excavation operation, and thus can improve the working efficiency of the excavator 100.

[0172] On the other hand, when it is determined that the excavation reaction force has not reached the target value (No in step ST11), the excavation support unit 57 does not execute the excavation support function and ends the current support process.

[0173] In addition, the excavation support unit 57 can also be configured to execute other excavation support functions when it is determined that the excavation reaction force has not reached the target value. Other excavation support functions are, for example, the equipment guidance function or the equipment control function. Specifically, the excavation support unit 57 can also be configured to, when the MC switch is pressed and the arm is closed, automatically operate at least one of the boom cylinder 7 and the bucket cylinder 9 so that the control point set on the tip of the bucket 6 moves horizontally upward toward the upper swing body 3. According to this configuration, the operator of the excavator 100 can, in a state where the tip of the bucket 6 has entered the desired depth, horizontally move the tip closer to the excavator 100 to perform the excavation operation. Moreover, the operator can achieve an appropriate excavation amount by performing the boom raising operation when it is known that the excavation reaction force has reached the target value.

[0174] Next, with reference to Figure 8 and Figure 9 , another example of the process of the setting process will be described. Figure 8 is a flowchart showing another example of the process of the setting process. Figure 9 is a diagram of the excavator 100 for the excavation groove GR. Specifically, Figure 9 the left diagram (upper left, central left, and lower left) is a cross-sectional view of the foundation to be excavated, Figure 9 the right diagram is a top view of the excavator 100 for the excavation groove GR. And, Figure 9The upper left figure shows the state at the start of the latter half of the first excavation operation, Figure 9 The upper central figure shows the state at the start of the latter half of the second excavation operation, Figure 9 The lower left figure shows the state at the start of the latter half of the third excavation operation.

[0175] In Figure 8 and Figure 9 In the illustrated example, the target setting unit 56 of the controller 30 executes this setting process each time an excavation operation is completed until the target value is set. Specifically, the target setting unit 56 determines whether the excavation operation has been completed based on the outputs of the posture sensor, the cylinder pressure sensor, etc. Moreover, when the target setting unit 56 determines that the excavation operation has been completed, it executes this setting process.

[0176] In addition, in Figure 8 and Figure 9 In the illustrated example, the operator of the excavator 100 excavates a groove GR of a specified depth DP (refer to the left figure of Figure 9 ), and discharges the excavated sandy soil DS (refer to the right figure of Figure 9 ) to the ground surface around the groove GR. In addition, for the sake of explanation, Figure 9 The right figure of Figure 9 shows the sandy soil DS1 excavated and discharged by the first excavation operation, the sandy soil DS2 excavated and discharged by the second excavation operation, and the sandy soil DS3 excavated and discharged by the third excavation operation. And, as shown in the left figure of Figure 9 the operator of the excavator 100 in each excavation operation makes the tip of the bucket 6 reach the specified depth DP, and while moving the bucket 6 only horizontally by the desired excavation length along the length direction (X-axis direction) of the groove GR, excavates the groove GR. That is, the operator can excavate the groove GR in such a way that the trajectory of the tip of the bucket 6 (in the case of parallel movement) is substantially the same in each excavation operation, and can increase or decrease the weight of the sandy soil excavated by each excavation operation by increasing or decreasing the excavation length. This means that if the excavation lengths are the same, the weights of the excavated sandy soil are also substantially the same. And the operator can perform a traveling operation based on the lower traveling body 1 between the previous excavation operation and the current excavation operation. In addition, for the sake of explanation,

[0177] First, the target setting unit 56 determines whether a specified excavation operation has been performed (step ST21). Based on the determination of the target setting unit 56 and Figure 6is the same as the determination by the target setting unit 56 in step ST1. Additionally, the target setting unit 56 can also determine whether a prescribed excavation operation has been performed based on the change in the excavation reaction force calculated during the execution of the current excavation operation and the amount of sandy soil taken into the bucket 6 through the current excavation operation. In Figure 6 it is the same in step ST1 of

[0178] Moreover, when it is determined that the prescribed excavation operation has not been performed ( "No" in step ST21), the target setting unit 56 ends the current setting process without setting a target value.

[0179] On the other hand, when it is determined that the prescribed excavation operation has been performed ( "Yes" in step ST21), the target setting unit 56 obtains the relationship between the excavation reaction force and the excavation weight (step ST22). In the illustrated example, the target setting unit 56 generates a reference table that associates multiple values of the excavation reaction force and multiple values of the excavation weight in a one-to-one relationship based on the maximum value of the excavation reaction force calculated during the execution of the excavation operation determined to be the prescribed excavation operation and the calculated value of the weight of the sandy soil (excavation weight) taken into the bucket 6 through the excavation operation. At this time, it is desirable that the number of excavation operations determined to be the prescribed excavation operation is two or more. Additionally, the multiple values of the excavation reaction force can be the values of the horizontal component or the vertical component of the multiple excavation reaction forces.

[0180] Then, the target setting unit 56 sets a target value (step ST23). In the illustrated example, the target setting unit 56 derives the value of the excavation reaction force corresponding to the desired value of the excavation weight from the reference table generated in step ST22 and sets the value of the excavation reaction force as the target value. The desired value of the excavation weight can be a value preset by the operator of the excavator 100 or a value automatically calculated based on various information.

[0181] In addition, in Figure 8 and Figure 9 the illustrated example, the target setting unit 56 sets a target value based on obtaining the relationship between the excavation reaction force and the excavation weight from the information obtained during the excavation operation performed at the same work site on the same date. However, the target setting unit 56 can also set a target value based on obtaining the relationship between the excavation reaction force and the excavation weight from the information obtained during the excavation operation performed at the same work site on other dates. Or, the target setting unit 56 can also set a target value based on obtaining the relationship between the excavation reaction force and the excavation weight from the information obtained during the excavation operation performed at other work sites.

[0182] Next, referring to Figure 10 and Figure 11 another example of the flow of the setting process will be described.Figure 10 It is a flowchart showing another example of the process of setting processing. Figure 11 It is a top view of the excavator 100 that excavates the trench GR and loads the excavated sand and soil into the carriage CB of the dump truck 200. Specifically, Figure 11 It shows the states of the excavator 100 and the dump truck 200 during the tipping operation after the 4th excavation operation. And, Figure 11 It shows the sand and soil LS loaded into the carriage CB of the dump truck 200 through the loading operation including 4 excavation operations. And, Figure 11 The state of the excavator 100 when the 4th excavation operation is completed is shown by a dotted line. In addition, Figure 11 The method of excavating the trench GR in the illustrated example is the same as the method Figure 9 described for reference.

[0183] In Figure 10 and Figure 11 In the illustrated example, the target setting unit 56 of the controller 30 executes this setting process each time an excavation operation is completed until the target value is set. Specifically, the target setting unit 56 determines whether the excavation operation is completed based on the outputs of the posture sensor, the cylinder pressure sensor, etc. Moreover, when the target setting unit 56 determines that the excavation operation is completed, it executes this setting process. In addition, in Figure 10 In the illustrated example, it shows an example of the case where the excavator 100 excavates the trench GR with a specified depth DP while loading the excavated sand and soil into the carriage CB of the dump truck 200. The maximum load capacity of the dump truck 200 is 10 tons. And, in each excavation operation, the operator of the excavator 100 makes the tip of the bucket 6 reach the specified depth DP, and while moving the bucket 6 only horizontally by the desired excavation length along the length direction of the trench GR, excavates the trench GR. That is, the operator can excavate the trench GR in such a way that the trajectory of the tip of the bucket 6 is substantially the same in the first half of each excavation operation, and can increase or decrease the weight of the sand and soil excavated by each excavation operation by increasing or decreasing the excavation length. And the operator can perform the traveling operation based on the lower traveling body 1 between the previous excavation operation and the current excavation operation.

[0184] First, the target setting unit 56 determines whether a specified excavation operation has been performed (step ST31). The determination by the target setting unit 56 is the same as the determination by the target setting unit 56 in Figure 8 step ST21.

[0185] Moreover, when it is determined that the specified excavation operation has not been performed (\"No\" in step ST31), the target setting unit 56 does not set the target value and ends this setting process.

[0186] On the other hand, when it is determined that a specified digging operation has been performed (Yes in step ST31), the target setting unit 56 acquires the relationship between the digging reaction force and the digging weight (step ST32). The acquisition by the target setting unit 56 based on this is the same as the acquisition by the target setting unit 56 in step ST22 based on Figure 8 which is the same as the acquisition by the target setting unit 56 in step ST22.

[0187] Then, the target setting unit 56 acquires the target weight (step ST33). In the illustrated example, the target setting unit 56 identifies the maximum load capacity of the dump truck 200 from the image of the dump truck 200 captured by the camera S6F which is a space recognition device, and acquires this maximum load capacity as the target weight. Specifically, the target setting unit 56 uses image recognition technology to identify the size of the license plate, the size of the vehicle body, the height of the carriage CB, or the value displayed on the maximum load capacity sticker, etc., thereby identifying the maximum load capacity of the dump truck 200. In addition, the target setting unit 56 may receive the information (information related to the maximum load capacity) sent by the dump truck 200 through the communication device T1, and acquire this maximum load capacity as the target weight. Also, the target weight may be a value input through the input device 42.

[0188] Then, the target setting unit 56 sets the target value (step ST34). In the illustrated example, the target setting unit 56 sets the target value based on the relationship between the digging reaction force and the digging weight acquired in step ST32 and the target weight acquired in step ST33.

[0189] For example, when the target setting unit 56 loads 1.0 ton of sand and soil into the carriage CB of the dump truck 200 through the first excavation operation (the first excavation operation) performed before setting the target value, it is determined that the carriage CB of the dump truck 200 can be filled to capacity through the subsequent 9 excavation operations (the second excavation operation). This is because there are still 9.0 tons remaining until the maximum loading capacity of 10.0 tons is reached, and it can be inferred that 1.0 ton of sand and soil can be loaded into the carriage CB through one excavation operation. That is, the target setting unit 56 can derive the value obtained by rounding up the quotient of dividing the maximum loading capacity (10.0 tons) by the excavation weight (1.0 ton) based on the first excavation operation (10 times) as the number of excavation operations (required number of times) required to achieve the target weight. In addition, the first excavation operation is an excavation operation performed before setting the target value, and the second excavation operation is an excavation operation performed after setting the target value. At this time, the target setting unit 56 sets the maximum value of the excavation reaction force (the maximum excavation reaction force) during the first excavation operation as the target value for each of the second to tenth excavation operations. This is to perform excavation with the same magnitude of excavation reaction force as during the first excavation operation in each of the second to tenth excavation operations, and thus achieve the same magnitude of excavation weight (1.0 ton) as during the first excavation operation. At this time, the weight of the sand and soil loaded into the dump truck 200 through 10 excavation operations becomes 1.0 ton × 10 times = 10.0 tons. In addition, the weight of the sand and soil already loaded into the carriage CB of the dump truck 200 through the first excavation operation (the first excavation operation) before setting the target value is the excavation weight (1.0 ton) based on the first excavation operation, and this weight is also referred to as the "cumulative weight". Moreover, the weight of the sand and soil loaded into the carriage CB of the dump truck 200 through the second excavation operation (the second to tenth excavation operations) after setting the target value is the value obtained by subtracting the cumulative weight from the maximum loading capacity (9.0 tons), and this value is also referred to as the "remaining weight".

[0190] In this way, the target setting unit 56 can set the target value so that the same maximum excavation reaction force as that during the first excavation operation is achieved in the second excavation operation. Specifically, the target setting unit 56 can set the target value so that the second excavation operation, the number of which is obtained by subtracting the number of the first excavation operations already performed from the required number of times, can load the sand and soil with a weight obtained by subtracting the cumulative weight from the target weight into the carriage CB. Moreover, the target setting unit 56 can set the target value so that the weight of the sand and soil loaded into the carriage CB through each second excavation operation is approximately the same as the excavation weight during the first excavation operation. According to this configuration, the target setting unit 56 can cause the excavator 100 to operate so that the excavation weight based on each excavation operation is approximately the same.

[0191] Alternatively, when the target setting unit 56 determines that the dump truck 200 can be fully loaded by the subsequent 8 excavation operations (second excavation operation) after the first excavation operation (first excavation operation) that loads 1.2 tons of sandy soil into the carriage CB of the dump truck 200 before setting the target value. At this time, the target setting unit 56 can set the maximum excavation reaction force during the first excavation operation as the target value for each of the second to eighth excavation operations. This is to achieve the same excavation weight (1.2 tons) as that during the first excavation operation by excavating with the same magnitude of excavation reaction force as during the first excavation operation in each of the second to eighth excavation operations. And the target setting unit 56 can set a value equal to one-third of the maximum excavation reaction force during the first excavation operation as the target value for the ninth excavation operation. This is to achieve one-third of the excavation weight (0.6 tons) of the first excavation operation by excavating with one-third of the excavation reaction force of the first excavation operation during the ninth excavation operation. That is, at the end of the first excavation operation, the target setting unit 56 derives that the required number of times is 9 times. Moreover, the remaining weight of the sandy soil loaded into the carriage CB by the 8 second excavation operations becomes 1.2 tons × 7 times and 0.4 tons × 1 time, totaling 8.8 tons. And the remaining weight is added to the cumulative weight (1.2 tons × 1 time), which is the weight loaded into the carriage CB by one first excavation operation, to become the target weight (10.0 tons).

[0192] As described above, the target setting unit 56 can set the target value so that the maximum excavation reaction force that is selectively achieved during the second excavation operation is the same as the maximum excavation reaction force during the first excavation operation and smaller than it. Specifically, the target setting unit 56 can set the target value so that the sandy soil with a weight obtained by subtracting the cumulative weight from the target weight can be loaded into the carriage CB by the second excavation operation with the number of times obtained by subtracting the number of times of the first excavation operation that has been performed from the required number of times. And the target setting unit 56 can set the target value so that the excavation weight for as many times as possible is approximately the same as the excavation weight during the first excavation operation. According to this structure, the target setting unit 56 can make the excavator 100 operate so that the excavation weight based on the second excavation operation for as many times as possible is approximately the same as the excavation weight during the first excavation operation. On this basis, the target setting unit 56 can make the excavator 100 operate so that the sandy soil that conforms to the target weight is loaded into the carriage CB.

[0193] Alternatively, when the target setting unit 56 determines that the dump truck 200 can be loaded to its full capacity through the subsequent eight excavation operations (second excavation operation) after loading 1.2 tons of sand and soil into the cargo bed CB of the dump truck 200 through the first excavation operation (first excavation operation) performed before setting the target value. At this time, the target setting unit 56 can set a value equivalent to approximately 92% of the maximum excavation reaction force during the first excavation operation as the target value for each of the second to ninth excavation operations. This is to perform excavation with an excavation reaction force approximately 92% of the size during the first excavation operation in each of the second to ninth excavation operations, and achieve an excavation weight (1.1 tons) approximately 92% of the size during the first excavation operation. That is, at the end of the first excavation operation, the target setting unit 56 derives that the required number of times is 9 times. Moreover, the remaining weight, which is the weight of the sand and soil loaded into the cargo bed CB through the eight second excavation operations, becomes 1.1 tons × 8 times = 8.8 tons. Moreover, the remaining weight is added to the cumulative weight (1.2 tons × 1 time), which is the weight loaded into the cargo bed CB through one first excavation operation, to become the target weight (10.0 tons).

[0194] In this way, the target setting unit 56 can set the target value so that the maximum excavation reaction force achieved in each second excavation operation is smaller than the maximum excavation reaction force during the first excavation operation. Specifically, the target setting unit 56 can set the target value so that the sand and soil with a weight obtained by subtracting the cumulative weight from the target weight can be loaded into the cargo bed CB through the second excavation operation for the number of times obtained by subtracting the number of times of the first excavation operation already performed from the required number of times. Moreover, the target setting unit 56 can set the target value so that the weight of the sand and soil loaded into the cargo bed CB through each second excavation operation is approximately the same. With this structure, the target setting unit 56 can make the excavator 100 operate so that the excavation weight based on each second excavation operation is approximately the same. On this basis, the target setting unit 56 can make the excavator 100 operate so that the sand and soil corresponding to the target weight is loaded into the cargo bed CB.

[0195] Alternatively, when the target setting unit 56 determines that the dump truck 200 can be fully loaded with sand and soil through the subsequent seven excavation operations (second excavation operation) in the case where an average of 1.0 ton of sand and soil is loaded into the cargo bed CB of the dump truck 200 during three excavation operations (first excavation operation) performed before setting the target value respectively. At this time, the target setting unit 56 can set the value of the maximum average excavation reaction force equivalent to three excavation operations as the target value for each of the fourth to tenth excavation operations. This is to achieve an excavation weight (1.0 ton) equal to the average excavation weight during the three first excavation operations by excavating with an excavation reaction force of the same magnitude as the maximum average excavation reaction force during the three first excavation operations in each of the fourth to tenth excavation operations. That is, at the end of the third excavation operation, the target setting unit 56 derives that the required number of times is eight times. Moreover, the remaining weight, which is the weight of the sand and soil loaded into the cargo bed CB through the seven second excavation operations, becomes 1.0 ton × seven times = 7.0 tons. Moreover, the remaining weight is added to the cumulative weight (3.0 tons), which is the weight loaded into the cargo bed CB through the three first excavation operations, to become the target weight (10.0 tons).

[0196] In this way, the target setting unit 56 can set the target value so that the maximum excavation reaction force achieved in each second excavation operation is smaller than the maximum average excavation reaction force of multiple first excavation operations. Specifically, the target setting unit 56 can set the target value so that the sand and soil with a weight obtained by subtracting the cumulative weight from the target weight can be loaded into the cargo bed CB through the second excavation operation with the number of times obtained by subtracting the number of performed first excavation operations from the required number of times. Moreover, the target setting unit 56 can set the target value so that the weight of the sand and soil loaded into the cargo bed CB through each second excavation operation is approximately the same as the average excavation weight during the first excavation operation. According to this structure, the target setting unit 56 can make the excavator 100 operate so that the excavation weight based on each second excavation operation is approximately the same as the average excavation weight during the first excavation operation. On this basis, the target setting unit 56 can make the excavator 100 operate so that the sand and soil corresponding to the target weight is loaded into the cargo bed CB.

[0197] In addition, in the above example, the target setting unit 56 obtains the relationship between the excavation reaction force and the excavation weight as a linear relationship, but it can also obtain the relationship between the excavation reaction force and the excavation weight as a non-linear relationship.

[0198] Moreover, in the above example, the target setting unit 56 sets a value less than or equal to the excavation weight based on one first excavation operation as the target value, but it can also set a value greater than the excavation weight based on one first excavation operation as the target value.

[0199] As described above, the excavator 100 according to the embodiment of the present invention is as follows Figure 1 shown, comprising: a lower traveling body 1; an upper revolving body 3 rotatably mounted on the lower traveling body 1; an attachment device AT mounted on the upper revolving body 3; and a controller 30 as a control device that repeatedly calculates a digging reaction force based on information related to the digging action of the attachment device AT on a work object at a work site. Further, the controller 30 is configured to set a target value based on the digging reaction force calculated during one or more digging actions, and support each digging action performed after setting the target value related to the digging reaction force based on the target value related to the digging reaction force.

[0200] In addition, the one or more digging actions performed to set the target value are digging actions for grasping the characteristics of the ground or the like to be dug (such as hardness, viscosity, density, or the relationship between the digging amount and the digging reaction force), and can be digging actions performed according to the manual operation of the operator on the operation device 26, digging actions performed while receiving support based on the equipment guidance function or the equipment control function, or digging actions automatically performed regardless of the operation of the operation device 26.

[0201] Moreover, the one or more digging actions performed to set the target value can be digging actions for trial digging first performed at a work site, digging actions first performed every day at a work site, or digging actions performed whenever the characteristics of the object to be dug change due to rainfall or the like. Therefore, the target value can be configured to be reset by the operator pressing a predetermined switch.

[0202] According to this structure, the controller 30 can improve the work efficiency of the excavator 100. This is because the operator of the excavator 100 can make the digging amount achieved by each digging action consistent with the desired digging amount. That is, the operator of the excavator 100 can, for example, achieve a state where the bucket 6 is full of sand and soil immediately after each digging action.

[0203] The controller 30 may be configured to determine whether a predetermined digging action suitable for target value calculation has been performed based on information related to the digging action of the attachment device AT on a work object at a work site, and set a target value based on the digging reaction force calculated during the digging action determined to be the predetermined digging action.

[0204] In the above example, the controller 30 determines whether the desired excavation volume has been achieved based on the image of the bucket 6 immediately after the excavation operation is performed by the camera S6F. When it can be determined that the desired excavation volume has been achieved, it is determined that a specified excavation operation has been performed. Further, the controller 30 sets the maximum value of the excavation reaction force calculated during the excavation operation determined to be the specified excavation operation as the target value.

[0205] According to this configuration, the controller 30 can support the operation of the operator of the excavator 100 so that the maximum value of the excavation reaction force during each excavation operation after the target value is set is the same as the maximum value of the excavation reaction force during the specified excavation operation before the target value is set. Therefore, the controller 30 can suppress excessive deviation in the excavation volume caused by each excavation operation after the target value is set. As a result, the controller 30 can improve the working efficiency of the excavator 100.

[0206] The controller 30 may be configured to notify the operator of the situation where the current excavation reaction force reaches the target value during each excavation operation after the target value is set.

[0207] According to this configuration, the operator of the excavator 100 performs a boom raising operation when receiving the notification that the current excavation reaction force reaches the target value during each excavation operation, thereby enabling the desired excavation volume to be achieved.

[0208] The controller 30 may be configured to cause a specified actuator to automatically operate when the current excavation reaction force reaches the target value during each excavation operation after the target value is set.

[0209] According to this configuration, the operator of the excavator 100 can achieve the desired excavation volume only by performing a stick closing operation without considering the timing of performing the boom raising operation.

[0210] The controller 30 may be configured to cause a specified actuator to automatically operate during each excavation operation after the target value is set so that a point set at a specified part of the attachment moves linearly until the current excavation reaction force reaches the target value.

[0211] According to this configuration, for example, the operator of the excavator 100 can perform an excavation operation by horizontally moving the tip of the bucket 6 closer to the excavator 100 until the current excavation reaction force reaches the target value, by, after the tip of the bucket 6 enters the desired depth, pressing the MC switch and performing a stick closing operation. Further, when the current excavation reaction force reaches the target value, since the excavation support function as described above is executed, the operator can achieve the desired excavation volume.

[0212] Moreover, the excavator 100 according to an embodiment of the present invention, as Figure 5 shown, moves (loads) an object such as sand to a specified place such as the carriage CB of the dump truck 200 or the ground by repeating a series of actions including a digging action and a dumping action. The excavator includes: a lower traveling body 1; an upper revolving body 3 rotatably mounted on the lower traveling body 1; an attachment device AT mounted on the upper revolving body 3; a sensor mounted on the upper revolving body 3; and a controller 30 as a control device that calculates, based on the output of the sensor, the digging reaction force generated by the digging action and the weight of the object taken into the bucket 6 and moved (loaded) to the specified place, i.e., the digging weight (loading weight). The digging weight is also referred to as the "moving weight". Further, the controller 30 sets a target value related to the digging reaction force during one or more subsequent second digging actions based on the relationship between the digging reaction force and the digging weight calculated during one or more first digging actions. The sensor includes at least one of a posture sensor, a cylinder pressure sensor, and a space recognition device. In addition, the first digging action is a digging action performed before setting the target value, and the second digging action is a digging action performed after setting the target value.

[0213] This configuration has the effect of being able to calculate more accurately the weight of the object moved to the specified place. For example, compared with the case where the correspondence between the digging reaction force and the moving weight (digging weight or loading weight) is not utilized, this configuration can derive a more accurate digging weight. This is because the digging reaction force is not affected by external disturbances generated when the bucket 6 is lifted into the air.

[0214] Moreover, this configuration has the effect of being able to control the weight (moving weight) of an object such as sand moved to the specified place by each second digging action performed after setting the target value. Therefore, this configuration can suppress a large deviation in the moving weight caused by each digging action based on multiple second digging actions.

[0215] Further, the excavator 100 operates in such a way that the weight of the object moved to the specified place by repeating a series of actions including a digging action and a dumping action becomes the target weight. Moreover, the controller 30 may be configured to set a target value related to the digging reaction force during the second digging action based on the relationship between the digging reaction force and the digging weight calculated during the first digging action, the weight of the object that has already been moved to the specified place, i.e., the cumulative weight, and the target weight.

[0216] This configuration has the following effect: it can control the moving weight based on each second digging action so that the moving weight based on one or more second digging actions performed after setting the target value does not exceed the remaining weight, which is the difference between the target weight and the cumulative weight.

[0217] Further, the controller 30 may also be configured to calculate the required number of excavation operations (required number) until the weight of the object moved to the specified location reaches the target weight based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation operation, the cumulative weight, and the target weight, and set a target value related to the excavation reaction force during the second excavation operation according to this number.

[0218] This structure has the following effect: it can control the moving weight based on each second excavation operation so that the moving weight based on one or more second excavation operations performed after setting the target value becomes the weight obtained by dividing the remaining weight by the required number. Therefore, this structure can prevent the moving weight based on a certain second excavation operation from becoming extremely large or extremely small, and thus can improve the fuel consumption rate of the excavator 100.

[0219] Further, the excavator 100 according to the embodiment of the present invention operates in such a way that the weight of an object such as sand moved to a specified location such as the carriage CB of the dump truck 200 or the ground reaches the target weight by repeating a series of operations including an excavation operation and a dumping operation. The excavator 100 includes: a lower traveling body 1; an upper revolving body 3 rotatably mounted on the lower traveling body 1; an attachment device AT mounted on the upper revolving body 3; a sensor mounted on the upper revolving body 3; and a controller 30 as a control device that calculates the excavation reaction force generated by the excavation operation and the weight of the object taken into the bucket 6, i.e., the excavation weight, based on the output of the sensor. Moreover, the controller 30 sets a target value related to the excavation reaction force during one or more second excavation operations performed later based on the relationship between the excavation reaction force and the excavation weight calculated during one or more first excavation operations and the target weight. Figure 5 This structure has the effect of easily making the weight of the object moved to the specified location consistent with the target weight. This is because the target value related to the excavation reaction force is set such that when the maximum excavation reaction force consistent with the target value is achieved during each second excavation operation, the weight of the object moved to the specified location is made consistent with the target weight.

[0220] This structure has the effect of easily making the weight of the object moved to the specified location consistent with the target weight. This is because the target value related to the excavation reaction force is set such that when the maximum excavation reaction force consistent with the target value is achieved during each second excavation operation, the weight of the object moved to the specified location is made consistent with the target weight.

[0221] Further, the controller 30 may be configured to set a target value related to the digging reaction force during the second digging operation based on the relationship between the digging reaction force and the digging weight calculated during one or more digging operations performed before the first digging operation and the target weight, when the digging reaction force or the digging weight calculated during the first digging operation is an abnormal value. The digging reaction force is determined as an abnormal value, for example, when it falls outside the range between a preset upper limit value and a preset lower limit value. The same applies to the digging weight. At this time, for example, when it is determined that the digging reaction force calculated during the third first digging operation among the three first digging operations is an abnormal value, the controller 30 sets a target value related to the digging reaction force during the second digging operation based on the relationship between the digging reaction forces and the digging weights calculated during the first and second first digging operations and the target weight.

[0222] This configuration can prevent setting the target value based on the abnormal value. Therefore, this configuration has the effect of being able to calculate more accurately the weight of the object moved to the specified location.

[0223] Further, the controller 30 may be configured to notify the operator that the current digging reaction force has reached the target value during each second digging operation after the target value is set. For example, the controller 30 can transmit to the operator that the current digging reaction force has reached the target value through a display device 40 or a sound output device 43, etc. At this time, the operator who recognizes that the current digging reaction force has reached the target value performs a boom raising operation at this moment to raise the boom 4 and lift at least a part of the bucket 6 located underground into the air, thereby enabling the digging weight (loading weight) corresponding to the target value related to the digging reaction force to be achieved.

[0224] Therefore, this configuration has the effect of easily making the weight of the object moved to the specified location consistent with the target weight. This is because, regarding the digging weight based on each second digging operation, when the boom raising operation is performed when the digging reaction force corresponding to the target value is generated, the digging weight (target digging weight) corresponding to the target value (digging reaction force) is achieved, and the greater the deviation of the digging reaction force during the boom raising operation from the target value, the greater the difference between the target digging weight and the actual digging weight becomes.

[0225] Further, the controller 30 may be configured to, in each second excavation operation performed after setting the target value, automatically operate a prescribed actuator when the current excavation reaction force reaches the target value. For example, the controller 30 (automatic control unit 54) can automatically adjust the pilot pressure applied to the pilot port of the control valve corresponding to the boom cylinder 7. Thereby, the controller 30 (automatic control unit 54) raises the boom 4 and lifts at least a part of the bucket 6 located underground into the air, thereby enabling the excavation weight (loading weight) corresponding to the target value related to the excavation reaction force to be achieved.

[0226] Therefore, this configuration has the effect of more easily making the weight of the object moved to the prescribed place coincide with the target weight. This is because the boom 4 can be raised at a more appropriate moment compared to the case where the boom raising operation is performed manually.

[0227] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, nor to the embodiments described later. The above-described or later-described embodiments can be applied with various modifications or replacements within the scope not departing from the present invention. Further, as long as there is no technical contradiction, the features described separately can be combined.

[0228] For example, the excavator 100 may be a remotely operated excavator. In this case, the controller 30 may be a control device provided in a remote operation room located outside the excavator 100. Further, the excavator 100 may also be an autonomous excavator that does not require the operation of an operator.

Claims

1. An excavator that moves an object to a predetermined location by repeating a series of actions including an excavation action and a dumping action, the excavator comprising: Lower walking body; An upper rotating body, rotatably mounted on the lower walking body; An auxiliary device, mounted on the upper rotating body; A sensor installed on the upper rotating body; and The control device calculates the excavation reaction force generated by the excavation action and the weight of the object taken into the bucket and moved to the location, that is, the excavation weight, based on the output of the sensor. The control device sets a target value for the excavation reaction force during one or more second excavation operations to be performed subsequently, based on the relationship between the excavation reaction force and the excavation weight calculated during one or more first excavation operations.

2. The shovel according to claim 1, which operates so that the weight of the object moved to the site by repeating a series of operations including an excavation operation and a dumping operation becomes a target weight, wherein: The control device sets a target value related to the excavation reaction force during the second excavation action based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation action, the weight of the objects moved to the location, i.e., the accumulated weight, and the target weight.

3. The excavator according to claim 2, wherein: The control device calculates the number of excavation actions required until the weight of the object moved to the location reaches the target weight based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation action, the accumulated weight and the target weight, and sets a target value related to the excavation reaction force during the second excavation action based on the number of times.

4. An excavator that operates so that the weight of an object moved to a predetermined location by repeating a series of operations including an excavation operation and a dumping operation becomes a target weight, the excavator comprising: Lower walking body; An upper rotating body, rotatably mounted on the lower walking body; An auxiliary device, mounted on the upper rotating body; A sensor installed on the upper rotating body; and The control device calculates the excavation reaction force generated by the excavation action and the weight of the object taken into the bucket, that is, the excavation weight, based on the output of the sensor. The control device sets a target value for the excavation reaction force during one or more second excavation operations to be performed subsequently, based on the relationship between the excavation reaction force and the excavation weight calculated during one or more first excavation operations and the target weight.

5. The excavator according to claim 4, wherein: When the excavation reaction force or excavation weight calculated during the first excavation action is an abnormal value, the control device sets a target value related to the excavation reaction force during the second excavation action based on the relationship between the excavation reaction force and the excavation weight calculated during one or more excavation actions performed before the first excavation action and the target weight.

6. The excavator according to any one of claims 1 to 5, wherein: The control device is configured to notify the operator that the current excavation reaction force has reached the target value in each of the second excavation operations performed after the target value is set.

7. The excavator according to any one of claims 1 to 5, wherein: The control device is configured to automatically operate a predetermined actuator when the current excavation reaction force reaches the target value in each of the second excavation operations performed after the target value is set.

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