backhoe

Abstract

The present application relates to a shovel (100) having a lower traveling body (1) including a track (1C), an upper swing body (3) swingably mounted on the lower traveling body (1), a traveling hydraulic motor (2M) driving the track (1C), a traveling lever (26D) corresponding to the traveling hydraulic motor (2M), a main pump (14) supplying working oil to the traveling hydraulic motor (2M), and a detection mechanism detecting an operation state of the traveling lever (26D). The shovel (100) is configured to suppress variation in the flow rate of working oil discharged from the main pump (14) in accordance with the detection result of the operation state.

Description

Technical Field

[0001] This invention relates to an excavator. Background Technology

[0002] Previously, an excavator equipped with a walking hydraulic motor was known (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2019 / 189935

[0006] Patent Document 2: Japanese Patent Application Publication No. 2004-340259 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, Patent Document 1 does not disclose a method for controlling the travel hydraulic motor when the excavator is moving in a curved path. Therefore, the aforementioned excavator may not be able to move smoothly in a curved path.

[0009] Therefore, it is preferable to provide an excavator that can smoothly move forward along a curved path.

[0010] Methods for solving problems

[0011] The excavator according to the embodiments of the present invention includes: a lower traveling body including tracks; an upper rotating body rotatably mounted on the lower traveling body; a traveling hydraulic motor driving the tracks; a traveling operating device corresponding to the traveling hydraulic motor; a hydraulic pump supplying working oil to the traveling hydraulic motor; and a detection mechanism detecting the operating state of the traveling operating device and suppressing fluctuations in the flow rate of the working oil discharged by the hydraulic pump based on the detection result of the operating state.

[0012] The effects of the invention

[0013] The excavator was able to move smoothly along a curved path. Attached Figure Description

[0014] Figure 1 This is a side view of the excavator according to an embodiment of the present invention.

[0015] Figure 2 yes Figure 1 A top view of an excavator.

[0016] Figure 3 It means that it is carried on Figure 1 A diagram illustrating the structure of the hydraulic system of an excavator.

[0017] Figure 4 This is a flowchart of the walking support process.

[0018] Figure 5 This is a graph illustrating the time progression of pump flow rate Q and operating pressure Pi in standalone walking operation.

[0019] Figure 6 This is another example of a graph showing the time progression of pump flow rate Q and operating pressure Pi in stand-alone walking operation.

[0020] Figure 7 This is another example of a graph showing the time progression of pump flow rate Q and operating pressure Pi in standalone walking operation.

[0021] Figure 8 It is a top view of the tracks moving in a curve to the left.

[0022] Figure 9 This is a diagram illustrating a structural example of the basic system of the construction machinery involved in this embodiment.

[0023] Figure 10 It means that it is carried on Figure 1 A schematic diagram of the structure of the hydraulic system of an excavator.

[0024] Figure 11A It is a diagram illustrating fluctuations and corresponding related information.

[0025] Figure 11B It is a diagram illustrating fluctuations and corresponding related information.

[0026] Figure 12 It is a flowchart illustrating the operation of an excavator.

[0027] Figure 13A This is a diagram illustrating the effects of this embodiment.

[0028] Figure 13B This is a diagram illustrating the effects of this embodiment.

[0029] Figure 14 This is a diagram illustrating an example of the structure of an electrically powered operating system. Detailed Implementation

[0030] First, refer to Figure 1 and Figure 2 The excavator 100, which is an excavator according to an embodiment of the present invention, will be described. Figure 1 This is a side view of excavator 100. Figure 2 This is a top view of the excavator 100.

[0031] In this embodiment, the lower traveling body 1 of the excavator 100 includes tracks 1C. Tracks 1C are driven by a travel hydraulic motor 2M mounted on the lower traveling body 1, which serves as a travel actuator. Specifically, tracks 1C include a left track 1CL and a right track 1CR. The left track 1CL is driven by a left travel hydraulic motor 2ML, and the right track 1CR is driven by a right travel hydraulic motor 2MR.

[0032] An upper rotating body 3 is rotatably mounted on the lower traveling body 1 via a rotating mechanism 2. The rotating mechanism 2 is driven by a rotary hydraulic motor 2A mounted on the upper rotating body 3, which serves as a rotary actuator. However, the rotary actuator can also be a rotary electric generator, which serves as an electric actuator.

[0033] A boom 4 is mounted on the upper rotating body 3. A stick 5 is mounted at the front end of the boom 4, and a bucket 6, serving as an end-connection accessory, is mounted at the front end of the stick 5. The boom 4, stick 5, and bucket 6 constitute an excavation accessory as an example of an accessory AT. The boom 4 is driven by a boom cylinder 7, the stick 5 is driven by a stick cylinder 8, and the bucket 6 is driven by a bucket cylinder 9. The boom cylinder 7, stick cylinder 8, and bucket cylinder 9 constitute the actuator of the accessory.

[0034] The boom 4 is supported vertically by the upper slewing body 3. A boom angle sensor S1 is mounted on the boom 4. The boom angle sensor S1 can detect the rotation angle of the boom 4, i.e., the boom angle θ1. The boom angle θ1 is, for example, the upward angle from the state where the boom 4 is at its maximum lowered position. Therefore, the boom angle θ1 is at its maximum when the boom 4 is at its maximum raised position.

[0035] The boom 5 is rotatably supported by the passive boom 4. Furthermore, a boom angle sensor S2 is mounted on the boom 5. The boom angle sensor S2 can detect the rotation angle of the boom 5, i.e., the boom angle θ2. The boom angle θ2 is, for example, the opening angle from the state where the boom 5 is maximally closed. Therefore, the boom angle θ2 is at its maximum when the boom 5 is maximally open.

[0036] The bucket 6 is rotatably supported by the boom 5. Furthermore, a bucket angle sensor S3 is installed on the bucket 6. The bucket angle sensor S3 can detect the rotation angle of the bucket 6, i.e., the bucket angle θ3. The bucket angle θ3 is the opening angle from the state where the bucket 6 is maximally closed. Therefore, the bucket angle θ3 is at its maximum when the bucket 6 is maximally open.

[0037] exist Figure 1In this embodiment, the boom angle sensor S1, stick angle sensor S2, and bucket angle sensor S3 are each composed of a combination of an accelerometer and a gyroscope sensor. However, they can also be composed of only an accelerometer. Furthermore, the boom angle sensor S1 can be a stroke sensor installed on the boom cylinder 7, or it can be a rotary encoder, a potentiometer, an inertial measurement device, etc. The same applies to the stick angle sensor S2 and the bucket angle sensor S3.

[0038] A cockpit 10, serving as the flight deck, is mounted on the upper rotating body 3 and is equipped with a power source such as an engine 11. Furthermore, a spatial recognition device 70, an orientation detection device 71, a positioning device 73, a fuselage tilt sensor S4, and a slewing angular velocity sensor S5 are installed on the upper rotating body 3. Inside the cockpit 10 are operating devices 26, a controller 30, an information input device 72, a display device D1, and a sound output device D2. Additionally, for convenience, in this specification, the side of the upper rotating body 3 where the auxiliary device AT is installed is designated as the front, and the side where the counterweight is installed is designated as the rear.

[0039] The spatial recognition device 70 is configured to identify objects existing in the three-dimensional space surrounding the excavator 100. Furthermore, the spatial recognition device 70 is configured to calculate the distance from the spatial recognition device 70 or the excavator 100 to the identified object. The spatial recognition device 70 can be, for example, an ultrasonic sensor, millimeter-wave radar, a monocular camera, a stereo camera, a LiDAR, a distance image sensor, or an infrared sensor. In this embodiment, the spatial recognition device 70 is a LiDAR, configured to emit multiple laser beams in multiple directions and receive their reflected light, thereby calculating the distance and direction of the object based on the reflected light. The same applies to cases where the spatial recognition device 70, such as a millimeter-wave radar, emits electromagnetic waves towards the object. Specifically, the spatial recognition device 70 includes a front sensor 70F mounted on the front end of the upper surface of the cab 10, a rear sensor 70B mounted on the rear end of the upper surface of the upper rotating body 3, a left sensor 70L mounted on the left end of the upper surface of the upper rotating body 3, and a right sensor 70R mounted on the right end of the upper surface of the upper rotating body 3. An overhead sensor that identifies objects in the space above the upper rotating body 3 can also be installed on the excavator 100.

[0040] The spatial recognition device 70 can be configured to capture images of the area around the excavator 100. In this case, the spatial recognition device 70 is, for example, a monocular camera with imaging elements such as CCD or CMOS, and outputs the captured images to the display device D1.

[0041] The spatial recognition device 70 can be configured to detect specified objects within a defined area surrounding the excavator 100. That is, the spatial recognition device 70 can be configured to identify at least one of the following: object type, location, and shape. For example, the spatial recognition device 70 can also be configured to distinguish between people and objects other than people. Furthermore, the spatial recognition device 70 can also be configured to determine the type of terrain surrounding the excavator 100. Terrain types include, for example, pits, slopes, or rivers. Furthermore, the spatial recognition device 70 can also be configured to determine the type of obstacles. Obstacle types include, for example, power lines, utility poles, people, animals, vehicles, construction equipment, construction machinery, buildings, or fences. Furthermore, the spatial recognition device 70 can also be configured to determine the type or size of a dump truck, for example, a vehicle. Furthermore, the spatial recognition device 70 can also be configured to detect people by recognizing helmets, safety vests, or work clothes, or by recognizing specified markings on helmets, safety vests, or work clothes. Furthermore, the spatial recognition device 70 can also be configured to recognize the condition of the road surface. Specifically, the spatial recognition device 70 may also be configured to determine the types of objects present on the road surface. Examples of objects present on the road surface include cigarettes, cans, plastic bottles, or stones.

[0042] The orientation detection device 71 is configured to detect information related to the relative orientation between the upper rotating body 3 and the lower traveling body 1. The orientation detection device 71 may be, for example, a combination of a geomagnetic sensor mounted on the lower traveling body 1 and a geomagnetic sensor mounted on the upper rotating body 3. Alternatively, the orientation detection device 71 may be a combination of a GNSS receiver mounted on the lower traveling body 1 and a GNSS receiver mounted on the upper rotating body 3. The orientation detection device 71 may be a rotary encoder, a rotary position sensor, etc. In a structure where the upper rotating body 3 is driven by a rotary electric generator, the orientation detection device 71 may also be a rotary transformer. The orientation detection device 71 may also be mounted, for example, at a central joint associated with a rotary mechanism 2, which enables relative rotation between the lower traveling body 1 and the upper rotating body 3.

[0043] The orientation detection device 71 can also be configured as a camera mounted on the upper rotating body 3. In this case, the orientation detection device 71 performs known image processing on the image (input image) captured by the camera mounted on the upper rotating body 3 to detect the image of the lower traveling body 1 included in the input image. Furthermore, the orientation detection device 71 determines the length direction of the lower traveling body 1 by detecting the image of the lower traveling body 1 using known image recognition technology. It also derives the angle formed between the front-rear axis direction of the upper rotating body 3 and the length direction of the lower traveling body 1. The front-rear axis direction of the upper rotating body 3 is derived based on the camera's mounting position. In particular, since the track 1C protrudes from the upper rotating body 3, the orientation detection device 71 can determine the length direction of the lower traveling body 1 by detecting the image of the track 1C. In this case, the orientation detection device 71 can be integrated into the controller 30.

[0044] The information input device 72 is configured to allow the excavator operator to input information to the controller 30. In this embodiment, the information input device 72 is a switch panel located near the display unit of the display device D1. However, the information input device 72 can be a touch panel located on the display unit of the display device D1, or it can be a voice input device such as a microphone located in the cab 10. Furthermore, the information input device 72 can also be a communication device. In this case, the operator can input information to the controller 30 via a communication terminal such as a smartphone.

[0045] The positioning device 73 is configured to determine the current position. In this embodiment, the positioning device 73 is a GNSS receiver that detects the position of the upper rotating body 3 and outputs the detected value to the controller 30. The positioning device 73 can also be a GNSS compass. In this case, the positioning device 73 can detect the position and orientation of the upper rotating body 3.

[0046] The body tilt sensor S4 detects the tilt angle of the upper rotating body 3 relative to a predetermined plane. In this embodiment, the body tilt sensor S4 is an acceleration sensor that detects the tilt angle of the upper rotating body 3 relative to the horizontal plane around the front and rear axes and the tilt angle around the left and right axes. The front and rear axes and the left and right axes of the upper rotating body 3 are, for example, orthogonal to each other and pass through a point on the rotation axis of the excavator 100, namely the center point of the excavator.

[0047] The rotational angular velocity sensor S5 detects the rotational angular velocity of the upper rotating body 3. In this embodiment, the rotational angular velocity sensor S5 is a gyroscope sensor. It can also be a rotary transformer, rotary encoder, etc. The rotational angular velocity sensor S5 can detect the rotational speed. The rotational speed can be calculated based on the rotational angular velocity.

[0048] Hereinafter, at least one of the boom angle sensor S1, stick angle sensor S2, bucket angle sensor S3, body tilt sensor S4, and slewing angular velocity sensor S5 will also be referred to as a posture detection device. The posture of the auxiliary device AT is detected, for example, based on the outputs of the boom angle sensor S1, stick angle sensor S2, and bucket angle sensor S3 respectively.

[0049] Display device D1 is a device for displaying information. In this embodiment, display device D1 is a liquid crystal display installed in the driver's cab 10. However, display device D1 may also be a display of a communication terminal such as a smartphone.

[0050] The sound output device D2 is a device for outputting sound. The sound output device D2 includes at least one of a device for outputting sound to the operator inside the cab 10 and a device for outputting sound to workers outside the cab 10. It may also be a speaker attached to a communication terminal.

[0051] Operating device 26 is a device for an operator to operate the actuator.

[0052] The controller 30 is a control device for controlling the excavator 100. In this embodiment, the controller 30 is composed of a computer equipped with a CPU, RAM, NVRAM, ROM, etc. The controller 30 reads programs corresponding to each function from the ROM and loads them into the RAM, and then causes the CPU to execute the corresponding processing. These functions include, for example, equipment guidance functions that guide the operator in performing manual operations on the excavator 100, and equipment control functions that support the operator in performing manual operations on the excavator 100 or enable the excavator 100 to operate automatically or autonomously.

[0053] Next, refer to Figure 3 An example of the structure of the hydraulic system mounted on the excavator 100 will be described. Figure 3 This is a diagram illustrating a structural example of the hydraulic system mounted on an excavator 100. Figure 3 The mechanical power transmission system, working oil pipeline, pilot pipeline and electrical control system are represented by double lines, solid lines, dashed lines and dotted lines respectively.

[0054] The hydraulic system of the excavator 100 mainly includes an engine 11, a pump regulator 13, a main pump 14, a control pump 15, a control valve unit 17, an operating device 26, an output pressure sensor 28, an operating sensor 29, and a controller 30.

[0055] exist Figure 3 In this system, the hydraulic system is configured to circulate working oil from the main pump 14 driven by the engine 11 through the intermediate bypass line 40 or the parallel line 42 to the working oil tank.

[0056] Engine 11 is the drive source for excavator 100. In this embodiment, engine 11 is, for example, a diesel engine that operates at a specified speed. The output shaft of engine 11 is connected to the input shafts of main pump 14 and control pump 15.

[0057] The main pump 14 is configured to supply working oil to the control valve unit 17 via a working oil line. In this embodiment, the main pump 14 is a swashplate variable capacity hydraulic pump.

[0058] The pump regulator 13 is configured to control the discharge rate of the main pump 14. In this embodiment, the pump regulator 13 controls the discharge rate of the main pump 14 by adjusting the swashplate deflection angle of the main pump 14 according to control commands from the controller 30.

[0059] The control pump 15 is an example of a pilot pressure generating device, and is configured to supply working oil via a pilot line to a hydraulic control device including the operating device 26. In this embodiment, the control pump 15 is a fixed-capacity hydraulic pump. However, the pilot pressure generating device can be implemented by the main pump 14. That is, in addition to supplying working oil to the control valve unit 17 via a working oil line, the main pump 14 can also supply working oil via a pilot line to various hydraulic control devices including the operating device 26. In this case, the control pump 15 can be omitted.

[0060] The control valve unit 17 is a hydraulic control device for controlling the hydraulic system in the excavator 100. In this embodiment, the control valve unit 17 includes control valves 171 to 176. Control valve 172 includes control valve 172L and control valve 172R, control valve 175 includes control valve 175L and control valve 175R, and control valve 176 includes control valve 176L and control valve 176R. The control valve unit 17 is configured to selectively supply working oil discharged from the main pump 14 to one or more hydraulic actuators via the control valves 171 to 176. For example, the control valves 171 to 176 control the flow rate of working oil from the main pump 14 to the hydraulic actuators and the flow rate of working oil from the hydraulic actuators to the working oil tank. The hydraulic actuators include a boom cylinder 7, a stick cylinder 8, a bucket cylinder 9, a left travel hydraulic motor 2ML, a right travel hydraulic motor 2MR, and a swing hydraulic motor 2A.

[0061] The operating device 26 is a device for an operator to operate the actuator. The operating device 26 includes, for example, an operating lever and an operating pedal. The actuator includes at least one of a hydraulic actuator and an electric actuator. In this embodiment, the operating device 26 is configured to supply working oil discharged from the control pump 15 via a pilot line to the pilot port of the corresponding control valve within the control valve unit 17. The pressure of the working oil supplied to each pilot port (pilot pressure) corresponds to the operating direction and amount of the operating device 26 corresponding to each hydraulic actuator. However, the operating device 26 may also be electrically controlled, instead of the pilot pressure type as described above. In this case, the control valve within the control valve unit 17 may be a solenoid spool valve.

[0062] The discharge pressure sensor 28 is configured to detect the discharge pressure of the main pump 14, which is an example of loop pressure. The loop pressure is the pressure of the working oil in the hydraulic circuit of the excavator 100. In this embodiment, the discharge pressure sensor 28 outputs the detected value to the controller 30.

[0063] The operating pressure sensor 29 is an example of a detection mechanism for detecting the operating state of an operating device, and is configured to detect the operation performed by the operator on the operating device 26. In this embodiment, the operating pressure sensor 29 detects the operating direction and amount of the operating device 26 corresponding to each actuator in the form of pressure (operating pressure), and outputs the detected values ​​to the controller 30. The operation of the operating device 26 can be detected using sensors other than the operating pressure sensor.

[0064] The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates the working oil to the working oil tank via the left intermediate bypass line 40L or the left parallel line 42L, and the right main pump 14R circulates the working oil to the working oil tank via the right intermediate bypass line 40R or the right parallel line 42R.

[0065] The left middle bypass line 40L is the working oil line for control valves 172L, 173, 175L and 176L, which are configured in control valve unit 17. The right middle bypass line 40R is the working oil line for control valves 171, 172R, 174, 175R and 176R, which are configured in control valve unit 17.

[0066] Control valve 171 is a spool valve that functions as a straight-line travel valve. In this embodiment, control valve 171 can switch the flow of working oil to improve the straight-line travel of the lower traveling body 1, supplying working oil from the left main pump 14L to the left traveling hydraulic motor 2ML and the right traveling hydraulic motor 2MR respectively. Specifically, when traveling hydraulic motor 2M and another hydraulic actuator are operated simultaneously, control valve 171 switches so that the left main pump 14L can supply working oil to both the left traveling hydraulic motor 2ML and the right traveling hydraulic motor 2MR. On the other hand, when traveling hydraulic motor 2M is operated and the other hydraulic actuators are not operated, control valve 171 switches so that the left main pump 14L can supply working oil to the left traveling hydraulic motor 2ML and the right main pump 14L can supply working oil to the right traveling hydraulic motor 2MR.

[0067] The control valve 172L is a slide valve that switches the flow of working oil by supplying working oil discharged from the left main pump 14L to the left travel hydraulic motor 2ML and discharging working oil discharged from the left travel hydraulic motor 2ML to the working oil tank.

[0068] Control valve 172R is a slide valve used to switch the flow of working oil by supplying working oil discharged from the right main pump 14R to the right travel hydraulic motor 2MR and discharging working oil discharged from the right travel hydraulic motor 2MR to the working oil tank.

[0069] Control valve 173 is a spool valve that switches the flow of working oil by supplying working oil discharged from the left main pump 14L to the rotary hydraulic motor 2A and discharging working oil discharged from the rotary hydraulic motor 2A to the working oil tank.

[0070] Control valve 174 is a slide valve used to switch the flow of working oil by supplying working oil discharged from the right main pump 14R to the bucket cylinder 9 and discharging working oil from the bucket cylinder 9 to the working oil tank.

[0071] Control valve 175L is a slide valve that switches the flow of working oil by supplying working oil discharged from the left main pump 14L to the boom cylinder 7. Control valve 175R is a slide valve that switches the flow of working oil by supplying working oil discharged from the right main pump 14R to the boom cylinder 7 and discharging the working oil in the boom cylinder 7 to the working oil tank.

[0072] The control valve 176L is a slide valve used to switch the flow of working oil by supplying working oil discharged from the left main pump 14L to the boom cylinder 8 and discharging the working oil in the boom cylinder 8 to the working oil tank.

[0073] The control valve 176R is a slide valve used to switch the flow of working oil by supplying working oil discharged from the right main pump 14R to the boom cylinder 8 and discharging the working oil in the boom cylinder 8 to the working oil tank.

[0074] The left parallel line 42L is a working oil line connected in parallel with the left intermediate bypass line 40L. When the flow of working oil through the left intermediate bypass line 40L is restricted or cut off by one of the control valves 172L, 173, or 175L, the left parallel line 42L can supply working oil to a more downstream control valve. The right parallel line 42R is a working oil line connected in parallel with the right intermediate bypass line 40R. When the flow of working oil through the right intermediate bypass line 40R is restricted or cut off by one of the control valves 172R, 174, or 175R, the right parallel line 42R can supply working oil to a more downstream control valve.

[0075] Pump regulator 13 includes a left pump regulator 13L and a right pump regulator 13R. The left pump regulator 13L controls the output of the left main pump 14L by adjusting the swashplate deflection angle of the left main pump 14L according to the output pressure of the left main pump 14L. Specifically, the left pump regulator 13L, for example, adjusts the swashplate deflection angle of the left main pump 14L to reduce the output, based on an increase in the output pressure of the left main pump 14L. The same applies to the right pump regulator 13R. This is to ensure that the absorbed power (absorbed horsepower), represented by the product of output pressure and output, of the main pump 14 does not exceed the output power (output horsepower) of the engine 11.

[0076] The operating device 26 includes a left operating lever 26L and a right operating lever 26R as auxiliary operating devices, and a travel lever 26D as a travel operating device. The travel lever 26D as a travel operating device includes a left travel lever 26DL as a left travel operating device and a right travel lever 26DR as a right travel operating device.

[0077] The left operating lever 26L, serving as an auxiliary operating device, is used for rotation and operation of the boom 5. When operating in the forward / backward direction, the left operating lever 26L utilizes the working oil discharged from the control pump 15 to introduce a control pressure corresponding to the lever's operating amount into the pilot port of the control valve 176. Furthermore, when operating in the left / right direction, the working oil discharged from the control pump 15 utilizes the control pressure corresponding to the lever's operating amount into the pilot port of the control valve 173.

[0078] Specifically, when operated in the boom closing direction, the left operating lever 26L introduces working oil into the right pilot port of control valve 176L and the left pilot port of control valve 176R. Similarly, when operated in the boom opening direction, the left operating lever 26L introduces working oil into the left pilot port of control valve 176L and the right pilot port of control valve 176R. Furthermore, when operated in the left slewing direction, the left operating lever 26L introduces working oil into the left pilot port of control valve 173, and when operated in the right slewing direction, the left operating lever 26L introduces working oil into the right pilot port of control valve 173.

[0079] The right operating lever 26R, serving as an auxiliary operating device, is used to operate the boom 4 and the bucket 6. When operating in the forward / backward direction, the right operating lever 26R utilizes the working oil discharged from the control pump 15 to introduce control pressure corresponding to the lever's operating amount into the pilot port of the control valve 175. Furthermore, when operating in the left / right direction, the working oil discharged from the control pump 15 utilizes the working oil to introduce control pressure corresponding to the lever's operating amount into the pilot port of the control valve 174.

[0080] Specifically, when operating in the boom lowering direction, the right operating lever 26R introduces working fluid into the left pilot port of control valve 175R. Furthermore, when operating in the boom raising direction, the right operating lever 26R introduces working fluid into the right pilot port of control valve 175L and the left pilot port of control valve 175R. Moreover, when operating in the bucket closing direction, the right operating lever 26R introduces working fluid into the right pilot port of control valve 174, and when operating in the bucket opening direction, the right operating lever 26R introduces working fluid into the left pilot port of control valve 174.

[0081] The travel lever 26D is an example of a travel control device and is used for operating the track 1C. Specifically, the left travel lever 26DL, as an example of a left travel control device, is used for operating the left track 1CL. It can also be configured to be linked with the left travel pedal, which is another example of a left travel control device. When operating in the forward or backward direction, the left travel lever 26DL uses the working oil discharged by the control pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 172L. The right travel lever 26DR, as an example of a right travel control device, is used for operating the right track 1CR. It can also be configured to be linked with the right travel pedal, which is another example of a right travel control device. When operating in the forward or backward direction, the right travel lever 26DR uses the working oil discharged by the control pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 172R.

[0082] The discharge pressure sensor 28 includes discharge pressure sensor 28L and discharge pressure sensor 28R. Discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L and outputs the detected value to the controller 30. The same applies to discharge pressure sensor 28R.

[0083] The operating pressure sensor 29 includes operating pressure sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. Operating pressure sensor 29LA detects the operator's actions on the left operating lever 26L in the forward / backward direction in the form of pressure, and outputs the detected value to the controller 30. The actions may include, for example, the lever's operating direction and the amount of lever operation (lever operating angle).

[0084] Similarly, the operating pressure sensor 29LB detects the operator's actions on the left operating lever 26L in the left-right direction in the form of pressure, and outputs the detected value to the controller 30. The operating pressure sensor 29RA detects the operator's actions on the right operating lever 26R in the forward-backward direction in the form of pressure, and outputs the detected value to the controller 30. The operating pressure sensor 29RB detects the operator's actions on the right operating lever 26R in the left-right direction in the form of pressure, and outputs the detected value to the controller 30. The operating pressure sensor 29DL is an example of a detection mechanism for detecting the operating status of the walking operating device, and detects the operator's actions on the left walking lever 26DL in the forward-backward direction in the form of pressure, and outputs the detected value to the controller 30. The operating pressure sensor 29DR is an example of a detection mechanism for detecting the operating status of the walking operating device, and detects the operator's actions on the right walking lever 26DR in the forward-backward direction in the form of pressure, and outputs the detected value to the controller 30.

[0085] The controller 30 receives the output of the operating pressure sensor 29 and outputs control commands to the pump regulator 13 as needed to change the discharge rate of the main pump 14. Furthermore, the controller 30 receives the output of the control pressure sensor 19 located upstream of the throttle valve 18 and outputs control commands to the pump regulator 13 as needed to change the discharge rate of the main pump 14. The throttle valve 18 includes a left throttle valve 18L and a right throttle valve 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

[0086] In the left intermediate bypass line 40L, a left throttle 18L is positioned between the downstream control valve 176L and the working oil tank. Therefore, the flow of working oil discharged from the left main pump 14L is restricted by the left throttle 18L. Furthermore, the left throttle 18L generates a control pressure for controlling the left pump regulator 13L. This control pressure is an example of the loop pressure. A left control pressure sensor 19L is used to detect this control pressure and outputs the detected value to the controller 30. The controller 30 controls the discharge volume of the left main pump 14L by adjusting the swashplate deflection angle of the left main pump 14L according to this control pressure. The controller 30 is configured such that the higher the control pressure, the lower the discharge volume of the left main pump 14L; conversely, the lower the control pressure, the higher the discharge volume of the left main pump 14L. The discharge volume of the right main pump 14R is similarly controlled.

[0087] Specifically, such as Figure 3 As shown, in the standby state where none of the hydraulic actuators in the excavator 100 are operated, the working oil discharged from the left main pump 14L reaches the left throttle 18L through the left intermediate bypass line 40L. Furthermore, the flow of the working oil discharged from the left main pump 14L increases the control pressure upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge volume of the left main pump 14L to the minimum allowable discharge volume, thereby suppressing pressure loss (pumping loss) when the discharged working oil passes through the left intermediate bypass line 40L. On the other hand, when a particular hydraulic actuator is operated, the working oil discharged from the left main pump 14L flows into the operated hydraulic actuator via the control valve corresponding to the operated hydraulic actuator. Furthermore, the flow of the working oil discharged from the left main pump 14L reduces or eliminates the amount reaching the left throttle 18L, thereby reducing the control pressure upstream of the left throttle 18L. As a result, controller 30 increases the output of the left main pump 14L to ensure sufficient working oil circulation to the hydraulic actuator of the workpiece, thereby ensuring the actuation of the hydraulic actuator. Similarly, controller 30 also controls the output of the right main pump 14R.

[0088] Based on the above structure, Figure 3 The hydraulic system can suppress unnecessary energy consumption in the main pump 14 in standby mode. Unnecessary energy consumption includes pumping losses caused by the working oil discharged from the main pump 14 in the intermediate bypass line 40. Furthermore, when the hydraulic actuator is activated, Figure 3 The hydraulic system is able to reliably supply the required amount of working oil from the main pump 14 to the hydraulic actuator of the work object.

[0089] but, Figure 3 The hydraulic system shown is an example of a hydraulic system mounted on an excavator 100. The hydraulic system mounted on the excavator 100 is not limited to using systems such as... Figure 3The hydraulic system shown is a negative control method. For example, the hydraulic system mounted on the excavator 100 can also be a hydraulic system that utilizes a positive control method or a load sensing method.

[0090] Next, refer to Figure 4 An example of the process by which the controller 30 supports the movement of the excavator 100 when the walking operation device is operated (hereinafter referred to as "walking support processing") will be described. Figure 4 This is a flowchart of the walking support process. When the walking operation device is operated, the controller 30 repeatedly executes the walking support process at a predetermined control cycle.

[0091] In this embodiment, the controller 30 is configured to perform travel support processing to support the excavator 100's curved travel. Curved travel includes, for example, cases where the forward speed of the left track 1CL differs from the forward speed of the right track 1CR, causing the lower walking body 1 to move forward. That is, cases where the rotational speed of the left travel hydraulic motor 2ML differs from the rotational speed of the right travel hydraulic motor 2MR, causing the lower walking body 1 to move forward. When the forward speed of the left track 1CL is greater than the forward speed of the right track 1CR, the excavator 100 travels in a curved path to the right. In this case, the left track 1CL is also referred to as the outer track, and the right track 1CR is also referred to as the inner track. Similarly, when the forward speed of the left track 1CL is less than the forward speed of the right track 1CR, the excavator 100 travels in a curved path to the left. In this case, the left track 1CL is also referred to as the inner track, and the right track 1CR is also referred to as the outer track. Furthermore, if the forward speed of the left track 1CL is the same as the forward speed of the right track 1CR, the excavator 100 travels in a straight path.

[0092] For example, when making an excavator 100, which is traveling straight, move it to the left in a curved direction, the operator may adjust the left travel lever 26DL's forward movement by less than the right travel lever 26DR's forward movement. In this case, the operator may adjust only the left travel lever 26DL, only the right travel lever 26DR, or both the left and right travel levers 26DL and 26DR individually.

[0093] However, even if the operator reduces the left travel lever 26DL by a roughly constant percentage without changing the amount of the right travel lever 26DR, the excavator 100 sometimes cannot smoothly travel in a curved path to the left. That is, the travel trajectory of the track 1C sometimes results in a different trajectory than desired. This is because the condition of the road surface at the work site can change drastically. Furthermore, the condition of the road surface varies, including whether the soil forming the road surface is clay or sand, whether it is dry or wet, whether it has snow accumulation, the amount of unevenness, and whether it is uphill or downhill.

[0094] For example, if the slippage of the left track 1CL deteriorates (e.g., the coefficient of friction of the ground in contact with the left track 1CL increases), the travel load of the right track 1CR increases while it is moving forward, and the forward speed of the right track 1CR decreases. Therefore, the excavator 100 cannot move smoothly to the left in a curved path.

[0095] Alternatively, if the slippage of the left track 1CL improves (for example, the coefficient of friction of the ground in contact with the left track 1CL decreases), the left track 1CL drifts, and the excavator 100 cannot smoothly move in a curve to the left.

[0096] In cases of improper operation by the operator, the excavator 100 may also be unable to smoothly advance in a curved path to the left. This is because, for example, if the operator drastically reduces the amount of movement of the left travel lever 26DL, the travel load on the right track 1CR increases drastically, and the forward speed of the right track 1CR decreases drastically.

[0097] That is, it can be assumed that the reason why the excavator 100 cannot move smoothly along a curve is that the output of the main pump 14 changes drastically due to the drastic change in the travel load, and the value of the control command generated based on the operator's operation of the travel control device is not properly limited.

[0098] Therefore, in this embodiment, the controller 30 enables the excavator 100 to smoothly travel in a curved path when the operator performs an operation for curved travel.

[0099] First, the controller 30 determines whether it is in a travel-only operation state (step ST1). The travel-only operation state is one of the states of the excavator 100, and it is a state in which only the travel operation device in the operating device 26, which consists of the auxiliary device operating device and the travel operation device, is operated. Besides the travel-only operation state, the excavator 100 also includes a travel-combined operation state, a non-operation state, and an auxiliary device-only operation state. The travel-combined operation state is a state in which both the auxiliary device operating device and the travel operation device are operated simultaneously. The non-operation state is a state in which neither the auxiliary device operating device nor the travel operation device is operated. The auxiliary device-only operation state is a state in which only the auxiliary device operating device is operated.

[0100] In this embodiment, the controller 30 determines whether the excavator 100 is in a walking-only operation state based on the output of the operating pressure sensor 29. However, the controller 30 may also determine whether the excavator 100 is in a walking-only operation state based on the output of other devices, such as a sensor that detects the tilt of the walking rod 26D or a camera that captures the operation state of the walking rod, or other devices that serve as a detection mechanism for detecting the operation state of the walking operation device.

[0101] If the system determines that the operation is not a standalone walking operation ("No" in step ST1), the controller 30 terminates the current walking support process.

[0102] On the other hand, if the system is determined to be in a walking-only operation state ("Yes" in step ST1), the controller 30 detects the operation amount of the walking operation device (step ST2). In this embodiment, the controller 30 detects the operation amount of the left walking lever 26DL based on the output of the operating pressure sensor 29DL, and detects the operation amount of the right walking lever 26DR based on the output of the operating pressure sensor 29DR. The same applies to the case where the walking pedal is pressed.

[0103] Then, the controller 30 determines whether the difference between the left and right operation amounts is greater than or equal to a predetermined value (step ST3). This is to determine whether to perform a curved forward movement (turning operation). In this embodiment, the controller 30 determines whether the difference between the operation amount of the left travel lever 26DL and the operation amount of the right travel lever 26DR is greater than or equal to a predetermined value.

[0104] If the left-right difference of the operation is determined to be less than the specified value (No in step ST3), the controller 30 terminates the current walking support process.

[0105] On the other hand, if it is determined that the difference between the left and right sides of the operation amount is greater than or equal to a specified value ("Yes" in step ST3), the controller 30 will suppress the change in the pump flow command value within a specified range (step ST4).

[0106] The pump flow command value is a command value sent from the controller 30 to the pump regulator 13. The pump flow command value includes a left pump flow command value for the left pump regulator 13L corresponding to the left main pump 14L, and a right pump flow command value for the right pump regulator 13R corresponding to the right main pump 14R. In this embodiment, the discharge volume of the main pump 14 is configured to increase as the pump flow command value increases.

[0107] The specified range can be a pre-stored range or a dynamically derived range. For example, the specified range can be selected from a plurality of pre-stored ranges based on at least one of the current states of the main pump 14 and the current states of control valves 172L and 172R. Specifically, the specified range can be selected from a plurality of pre-stored ranges based on at least one of the left-right difference of the operating amount, circuit pressure, motor pressure, and engine speed. The specified range can also be changed based on whether the operation is abrupt. The left-right difference of the operating amount and whether the operation is abrupt are derived, for example, from the output of the operating pressure sensor 29. The motor pressure is, for example, the pressure of the working oil flowing into the travel hydraulic motor 2M. The pressure of the working oil flowing into the left travel hydraulic motor 2ML, i.e., the left motor pressure, can be detected, for example, by a pressure sensor installed in the pipeline connecting control valve 172L and the left travel hydraulic motor. The same applies to the pressure of the working oil flowing into the right travel hydraulic motor 2MR, i.e., the right motor pressure.

[0108] Thus, by suppressing the change in the pump flow command value per unit time within a specified range, the controller 30 can prevent excessive changes in the discharge volume of the main pump 14, even under conditions of rapid changes in the travel load or even under conditions of rapid operation of the travel control device by the operator. That is, even under conditions of rapid changes in the travel load or even under conditions of rapid operation of the travel control device by the operator, the controller 30 can slowly change the discharge volume of the main pump 14.

[0109] As a result, the controller 30 can prevent the actual travel trajectory from deviating too much from the travel trajectory that the operator wants to depict, thereby enabling the excavator 100 to move smoothly along a curved path.

[0110] Next, refer to Figure 5 An example is given regarding the time progression of pump flow rate Q and operating pressure Pi during the execution of walking support processing. Figure 5 This is an example illustrating the time progression of pump flow rate Q and operating pressure Pi in stand-alone travel operation. Pump flow rate Q in stand-alone travel operation includes the output of the left main pump 14L (supplying working oil to the left travel hydraulic motor 2ML), i.e., the left pump flow rate QL, and the output of the right main pump 14R (supplying working oil to the right travel hydraulic motor 2MR), i.e., the right pump flow rate QR. Operating pressure Pi includes the pilot pressure generated by the left travel lever 26DL (the pilot pressure acting on the pilot port of control valve 172L), i.e., the left operating pressure PiL, and the pilot pressure generated by the right travel lever 26DR (the pilot pressure acting on the pilot port of control valve 172R), i.e., the right operating pressure PiR.

[0111] Specifically, Figure 5 The graph above shows the pump flow rate Q over time. Figure 5In the graph above, the solid line represents the time elapsed for the left pump flow rate QL when travel support processing was performed, and the dotted line represents the time elapsed for the left pump flow rate QLa when travel support processing was not performed. Furthermore, Figure 5 The dashed line in the above figure represents the time elapsed for the right pump flow rate QR when travel support processing was performed, while the single-dotted line represents the time elapsed for the right pump flow rate QRa when travel support processing was not performed. Figure 5 The solid line in the figure below represents the time progression of the left operating pressure PiL associated with the left travel lever 26DL. Figure 5 The dashed line in the figure below represents the time progression of the right operating pressure PiR associated with the right travel lever 26DR.

[0112] exist Figure 5 In the example shown, the operator steers the excavator 100, which is traveling straight, to a leftward curve, and then performs the operation to propel the excavator 100 straight again. Specifically, at time t0, the operator adjusts the left travel lever 26DL by the same amount as the right travel lever 26DR. At this time, both the left operating pressure PiL and the right operating pressure PiR become value P1, and both the left pump flow rate QL and the right pump flow rate QR become value Q1.

[0113] Then, at time t1, the operator begins to reduce the amount of operation of the left travel lever 26DL, decreasing it by a roughly constant percentage until time t2 is reached. As a result, the left operating pressure PiL becomes value Pt1 at time t2 and value P2 at time t3. During this period, the operator maintains the amount of operation of the right travel lever 26DR. Therefore, the right operating pressure PiR is maintained at value P1.

[0114] Then, at time t4, the operator begins to increase the operating amount of the left travel lever 26DL, increasing it by a roughly constant percentage until time t5. As a result, the left operating pressure PiL returns to its value P1 at time t5. That is, the operating amount of the left travel lever 26DL is the same as the operating amount of the right travel lever 26DR. During this period, the operator maintains the operating amount of the right travel lever 26DR. Therefore, the right operating pressure PiR is maintained at its value P1.

[0115] If at time t2 the difference between the operation amount of the left travel lever 26DL and the operation amount of the right travel lever 26DR is determined to be above a specified value, then the controller 30 will... Figure 4 As shown in step ST4, the variation in the pump flow command value is suppressed within the specified range. Figure 5In the example shown, the controller 30 is configured such that when the difference between the left operating pressure PiL value Pt1 and the right operating pressure PiR value P1 becomes a predetermined pressure ΔP, it is determined that the difference between the operating amount of the left travel lever 26DL and the operating amount of the right travel lever 26DR is above a predetermined value. Furthermore, the controller 30 is configured to limit the left pump flow rate command value to a predetermined range defined by the upper limit TL1 (represented by a double-dotted line) and the lower limit BL1 (represented by a double-dotted line). As a result, the left pump flow rate QL becomes value Q2 at time t3. The right pump flow rate QR remains at value Q1. Additionally, the double-dotted lines only schematically represent the time progression of each value of the upper limit TL1 and the lower limit BL1, and do not represent the exact time progression of each value.

[0116] Specifically, the specified range is set as the difference between the left pump flow command value used in the previous control cycle (hereinafter referred to as the "previous command value") and the left pump flow command value used in the current control cycle, which is below the specified value.

[0117] Through this structure, the controller 30 can also appropriately handle situations such as: when, based on rapid changes in the walking load or the amount of operation, a left pump flow command value is temporarily calculated that is greater than or equal to a predetermined value but smaller than the previous command value. In this case, the controller 30 calculates the value obtained by subtracting the predetermined value from the previous command value as the final left pump flow command value used in the current control cycle, so that the difference between the previous command value and the final left pump flow command value used in the current control cycle is a predetermined value. That is, the controller 30 uses a value equivalent to the lower limit BL1 of the predetermined range as the final left pump flow command value used in the current control cycle.

[0118] Similarly, the controller 30 can also appropriately handle situations where a left pump flow command value is temporarily calculated that is greater than or equal to the previous command value and has a difference from the previous command value exceeding a predetermined value. In this case, the controller 30 calculates the value obtained by adding the predetermined value to the previous command value as the final left pump flow command value used in the current control cycle, so that the difference between the previous command value and the final left pump flow command value used in the current control cycle is the predetermined value. That is, the controller 30 uses a value equivalent to the upper limit TL1 of the predetermined range as the final left pump flow command value used in the current control cycle.

[0119] As a result, controller 30 is able to achieve the following: Figure 5 The solid line in the above figure represents the time progression of the left pump flow rate QL, which varies less, rather than achieving... Figure 5 The dotted line in the above figure represents the time progression of the significantly varying left pump flow rate QLa when no walk support processing was performed.

[0120] Furthermore, the controller 30 is capable of achieving the following: Figure 5 The above figure, represented by dashed lines, shows the time progression of the right pump flow rate QR with relatively small variations, rather than achieving... Figure 5 The above figure shows the time progression of the significantly fluctuating right pump flow rate QRa when no walk support processing was performed, indicated by a dashed line. This is because: Figure 5 In the example shown, the change in the right pump flow rate QR can be suppressed by suppressing the change in the left pump flow rate QL.

[0121] In addition, Figure 5 In the above figure, although the upper and lower limits of the specified range are not shown for the right pump flow rate QR as for the left pump flow rate QL, the controller 30 is configured to limit the right pump flow rate command value in order to limit the right pump flow rate QR within the specified range.

[0122] Furthermore, refer to Figure 5 The above description relates to the time progression of the pump flow rate Q when the excavator 100, which is moving straight, curves to the left, but it is equally applicable to the time progression of the pump flow rate Q when the excavator 100, which is moving to the left, curves to the left, moves straight again. Specifically, as... Figure 5 As shown in the figure above, the controller 30 is configured to limit the left pump flow rate command value within a specified range determined by the upper limit TL2 (represented by a double-dotted line) and the lower limit BL2 (represented by a double-dotted line). Furthermore, the double-dotted lines only schematically represent the time progression of each value of the upper limit TL2 and the lower limit BL2, and do not represent the precise time progression of each value.

[0123] Furthermore, refer to Figure 5 The above description can also be applied to the time progression of the pump flow rate Q when the excavator 100, which is moving straight, is turned to the right in a curved direction and when the excavator 100, which is turning to the right in a curved direction, is turned straight again.

[0124] Next, refer to Figure 6 Another example illustrating the time progression of pump flow rate Q and operating pressure Pi during the execution of walking support processing is provided. Figure 6 This is an example illustrating the time progression of pump flow rate Q and operating pressure Pi under stand-alone operation conditions, and is related to... Figure 5 correspond.

[0125] exist Figure 6 In the example shown, the operator performs an operation to steer the excavator 100, which is traveling straight, to a leftward curve. Specifically, at time t0, the operator adjusts the left travel lever 26DL by the same amount as the right travel lever 26DR. At this time, both the left operating pressure PiL and the right operating pressure PiR become value P11, and both the left pump flow rate QL and the right pump flow rate QR become value Q11.

[0126] Then, at time t1, the operator begins to increase the operating amount of the right travel lever 26DR, increasing it by a roughly constant percentage until time t3. As a result, the right operating pressure PiR becomes value Pt2 at time t2 and value P12 at time t3. During this period, the operator maintains the operating amount of the left travel lever 26DL. Therefore, the left operating pressure PiL is maintained at value P11.

[0127] If at time t2 the difference between the operation amount of the left travel lever 26DL and the operation amount of the right travel lever 26DR is determined to be above a specified value, then the controller 30 will... Figure 4 As shown in step ST4, the variation in the pump flow command value is suppressed within the specified range. Figure 6 In the example shown, the controller 30 is configured to determine that the difference between the operating amount of the left travel lever 26DL and the operating amount of the right travel lever 26DR is above a predetermined value when the difference between the left operating pressure PiL value P11 and the right operating pressure PiR value Pt2 becomes a predetermined pressure ΔP. Furthermore, the controller 30 is configured to limit the right pump flow command value to a predetermined range defined by the upper limit TL3 (indicated by double-dotted lines) and the lower limit BL3 (indicated by double-dotted lines). As a result, the right pump flow QR becomes value Q12 at time t3. The left pump flow QL remains at value Q11. Additionally, the double-dotted lines only schematically represent the time progression of the upper limit TL3 and lower limit BL3 values, and do not represent the exact time progression of each value. Specifically, the predetermined range is set when the difference between the previous command value and the right pump flow command value used in the current control cycle becomes below a predetermined value.

[0128] Through this structure, the controller 30 can also appropriately handle situations such as: when, due to rapid changes in the walking load or the amount of operation, a right pump flow command value is temporarily calculated that is greater than or equal to the previous command value and differs from it by a predetermined value. In this case, the controller 30 calculates the value obtained by adding the predetermined value to the previous command value as the final right pump flow command value used in the current control cycle, so that the difference between the previous command value and the final right pump flow command value used in the current control cycle is a predetermined value. That is, the controller 30 uses a value equivalent to the upper limit TL3 of the predetermined range as the final right pump flow command value used in the current control cycle.

[0129] Similarly, the controller 30 can also appropriately handle situations where a right pump flow command value is temporarily calculated that is greater than or equal to a predetermined value but smaller than the previous command value. In this case, the controller 30 calculates the value obtained by subtracting the predetermined value from the previous command value as the final right pump flow command value used in the current control cycle, so that the difference between the previous command value and the final right pump flow command value used in the current control cycle is a predetermined value. That is, the controller 30 uses a value equivalent to the lower limit BL3 of the predetermined range as the final right pump flow command value used in the current control cycle.

[0130] As a result, controller 30 is able to achieve the following: Figure 6 The above figure, represented by dashed lines, shows the time progression of the right pump flow rate QR with relatively small variations, rather than achieving... Figure 6 The figure above shows the time progression of the significantly varying right pump flow rate QRa when no walk support processing was performed, indicated by a single-dotted line.

[0131] Furthermore, the controller 30 is capable of achieving the following: Figure 6 The solid line in the above figure represents the time progression of the left pump flow rate QL, which varies less, rather than achieving... Figure 6 The dotted line in the above figure represents the time progression of the significantly fluctuating left pump flow rate QLa when no walk support processing was performed. This is because, in Figure 6 In the example shown, the variation in the left pump flow rate QL can be suppressed by suppressing the variation in the right pump flow rate QR.

[0132] In addition, Figure 6 In the above figure, although the upper and lower limits of the specified range are not shown for the left pump flow rate QL as they are for the right pump flow rate QR, the controller 30 is configured to limit the left pump flow rate command value in order to limit the left pump flow rate QL within the specified range.

[0133] Furthermore, refer to Figure 6 The above explanation relates to the time progression of the pump flow rate Q when the excavator 100, which is moving straight, curves to the left, but it is equally applicable to the time progression of the pump flow rate Q when the excavator 100, which is moving curves to the left, moves straight again. Furthermore, refer to... Figure 6 The above description can also be applied to the time progression of the pump flow rate Q when the excavator 100, which is moving straight, is turned to the right in a curved direction and when the excavator 100, which is turning to the right in a curved direction, is turned straight again.

[0134] Next, refer to Figure 7 Another example illustrating the time progression of pump flow rate Q and operating pressure Pi during the execution of walking support processing is provided. Figure 7This is an example illustrating the time progression of pump flow rate Q and operating pressure Pi under stand-alone operation conditions, and is related to... Figure 6 correspond.

[0135] exist Figure 7 In the example shown, the operator performs an operation to steer the excavator 100, which is traveling straight, to a leftward curve. Specifically, at time t0, the operator adjusts the left travel lever 26DL by the same amount as the right travel lever 26DR. At this time, both the left operating pressure PiL and the right operating pressure PiR become value P21, and both the left pump flow rate QL and the right pump flow rate QR become value Q21.

[0136] Then, at time t1, the operator begins to reduce the amount of operation of the right travel lever 26DR, decreasing it by a roughly constant percentage until time t3. As a result, the right operating pressure PiR becomes value Pt3 at time t2 and value P22 at time t3. Furthermore, at time t1, the operator begins to reduce the amount of operation of the left travel lever 26DL, decreasing it by a roughly constant percentage until time t3. As a result, the left operating pressure PiL becomes value Pt4 at time t2, which is smaller than the right operating pressure PiR value Pt3 at that time, and becomes value P23 at time t3, which is smaller than the right operating pressure PiR value P22 at that time.

[0137] If at time t2 the difference between the operation amount of the left travel lever 26DL and the operation amount of the right travel lever 26DR is determined to be above a specified value, then the controller 30 will... Figure 4 As shown in step ST4, the variation in the pump flow command value is suppressed within the specified range. Figure 7 In the example shown, the controller 30 is configured to determine that the difference between the operating amount of the left travel lever 26DL and the operating amount of the right travel lever 26DR is above a predetermined value when the difference between the left operating pressure PiL value Pt4 and the right operating pressure PiR value Pt3 becomes a predetermined pressure ΔP. Furthermore, the controller 30 is configured to limit the right pump flow command value to a predetermined range defined by the upper limit TL4 (indicated by double-dotted lines) and the lower limit BL4 (indicated by double-dotted lines). The controller 30 is also configured to limit the left pump flow command value to a predetermined range defined by the upper limit TL5 (indicated by double-dotted lines) and the lower limit BL5 (indicated by double-dotted lines). As a result, the right pump flow rate QR becomes value Q22 at time t3, and the left pump flow rate QL becomes value Q23 at time t3.

[0138] In addition, the double-dotted lines only indicate the passage of time for the values ​​of the upper limit TL4, upper limit TL5, lower limit BL4, and lower limit BL5 of the ground surface, and do not represent the exact passage of time for each value.

[0139] Specifically, the specified range is set as the difference between the previous command value and the pump flow command value used in the current control cycle being below the specified value.

[0140] Through this structure, the controller 30 can also appropriately handle situations such as: when, based on a sudden change in the walking load or the amount of operation, it temporarily calculates a pump flow command value that is greater than or equal to the previous command value and whose difference from the previous command value is greater than the previous command value. In this case, the controller 30 calculates the value obtained by adding the specified value to the previous command value as the final pump flow command value used in the current control cycle, so that the difference between the previous command value and the final pump flow command value used in the current control cycle is the specified value.

[0141] Similarly, the controller 30 can also appropriately handle situations where a pump flow command value is temporarily calculated that is greater than or equal to the previous command value but smaller than the previous command value. In this case, the controller 30 calculates the value obtained by subtracting the specified value from the previous command value as the final pump flow command value used in the current control cycle, so that the difference between the previous command value and the final pump flow command value used in the current control cycle is the specified value.

[0142] As a result, controller 30 is able to achieve the following: Figure 7 The above figure, represented by dashed lines, shows the time progression of the small variation in the right pump flow rate QR, rather than achieving... Figure 7 The figure above shows the time progression of the large variation in the right pump flow rate QRa when no walk support processing was performed, indicated by a single-dotted line.

[0143] Furthermore, the controller 30 is capable of achieving the following: Figure 7 The solid line in the above figure represents the time progression of the left pump flow rate QL with small variations, rather than achieving... Figure 7 The dotted line in the above figure represents the time progression of the large variation in the left pump flow rate QLa when no walk support processing was performed.

[0144] refer to Figure 7 The above explanation relates to the time progression of the pump flow rate Q when the excavator 100, which is moving straight, curves to the left, but it is equally applicable to the time progression of the pump flow rate Q when the excavator 100, which is moving curves to the left, moves straight again. Furthermore, refer to... Figure 7 The above description can also be applied to the time progression of the pump flow rate Q when the excavator 100, which is moving straight, is turned to the right in a curved direction and when the excavator 100, which is turning to the right in a curved direction, is turned straight again.

[0145] like Figures 5-7As shown, even when the pump flow command value changes drastically due to abrupt changes in the travel load or the amount of operation, the controller 30 can suppress the drastic changes in the pump flow command value ultimately output to the pump regulator 13. Therefore, for example, in the case where the operator performs operations for curved travel, the controller 30 can enable the excavator 100 to travel smoothly along a curved path.

[0146] Furthermore, even when the actual travel trajectory deviates from the trajectory the operator intends to depict, the controller 30 can suppress abrupt changes in the pump flow rate Q, even if the operator drastically manipulates the travel lever 26D to correct the travel trajectory. Therefore, the controller 30 can smoothly correct the operator's travel trajectory of the excavator 100.

[0147] Furthermore, the controller 30 can be configured to suppress fluctuations in the pilot pressure associated with the travel lever 26D when the operation is determined to be a travel-only operation. This is to prevent a sharp change in the pump flow rate Q when the travel lever 26D is operated abruptly. For example, if a solenoid valve capable of controlling the pilot pressure, which is the pressure on the secondary side of the travel lever 26D, is provided, the controller 30 can suppress fluctuations in the pilot pressure when the travel lever 26D is operated abruptly by controlling this solenoid valve.

[0148] Next, refer to Figure 8 An example illustrating the effect of walking support processing is provided. Figure 8 This is a top view of track 1C moving in a curved direction to the left. Figure 8 For clarity, the diagrams of components constituting the excavator 100, excluding the tracks 1C, are omitted. The dashed line PL represents the travel trajectory of the left track 1CL when travel support processing is performed, and the dashed line PR represents the travel trajectory of the right track 1CR when travel support processing is performed. The single-dotted line PLA represents the travel trajectory of the left track 1CL when travel support processing is not performed, and the single-dotted line PRa represents the travel trajectory of the right track 1CR when travel support processing is not performed. Furthermore, the operation of the travel lever 26D when travel support processing is performed is the same as the operation of the travel lever 26D when travel support processing is not performed.

[0149] like Figure 8 As shown by the single-dotted line, when the travel support process is not executed, track 1C moves to the left in a serpentine curve. However, when the travel support process is executed, track 1C moves to the left in a smooth arc.

[0150] Furthermore, by guiding the excavator 100 to move in a leftward curved path in a smooth arc, the controller 30 prevents unnecessary increases in travel distance due to serpentine movements. As a result, the controller 30 achieves energy-saving effects such as reduced fuel consumption.

[0151] Furthermore, by preventing excessive fluctuations in the discharge volume of the main pump 14 during curved travel, the controller 30 can prevent repeated increases and decreases in travel load caused by improper operation of the travel lever 26D by the operator. In this respect, the controller 30 can also achieve energy-saving effects.

[0152] As described above, the excavator 100 according to the embodiments of the present invention includes: a lower traveling body 1, including tracks 1C; an upper rotating body 3, rotatably mounted on the lower traveling body 1; a traveling hydraulic motor 2M, driving the tracks 1C; a traveling lever 26D as a traveling operation device, corresponding to the traveling hydraulic motor 2M; a main pump 14 as a hydraulic pump, supplying working oil to the traveling hydraulic motor 2M; and a detection mechanism for detecting the operating status of the traveling operation device. Furthermore, the excavator 100 is configured to suppress fluctuations in the flow rate of the working oil discharged by the main pump 14 based on the detection results of the operating status. The main pump 14 can be an electrically controlled variable capacity hydraulic pump. With this structure, the excavator 100 can smoothly advance along curved paths.

[0153] Furthermore, in the above embodiment, the track 1C has a left track 1CL and a right track 1CR. Also, the travel lever 26D, which serves as the travel operation device, has a left travel lever 26DL corresponding to the left track 1CL and serving as the left travel operation device, and a right travel lever 26DR corresponding to the right track 1CR and serving as the right travel operation device.

[0154] Therefore, the excavator 100 can be configured such that, when there is a predetermined difference between the operation of the left travel lever 26DL and the operation of the right travel lever 26DR, it is determined that the lower travel body 1 is moving forward in a curve, and the change in the flow rate of the working oil discharged by the main pump 14 is suppressed.

[0155] For example, a specified difference is generated when the operating amount of one of the left travel lever 26DL and the right travel lever 26DR is increased, when the operating amount of one is decreased, when the operating amount of both is increased, or when the operating amount of both is decreased.

[0156] The excavator 100 can be configured to suppress changes in a command value, i.e., a pump flow command value, related to the flow rate of the working oil discharged from the main pump 14, based on the pressure of the working oil flowing through the hydraulic circuit or the amount of operation of the travel lever 26D. In this case, at least one of an upper limit and a lower limit can be set for the change in the command value.

[0157] Hereinafter, another embodiment of the present invention will be described with reference to the accompanying drawings.

[0158] Previously, an excavator was known to be driven by a hydraulic motor (see Patent Document 2). Furthermore, it is known that conventional excavators have pedals on the floor (ground) of the cab operated by the driver's feet, and move according to the driver's forward and backward pedal operations.

[0159] When the operator is pressing the pedals, their body is in an unstable position, primarily supported by their hips. Therefore, if the machine shakes due to uneven ground, unexpected acceleration, or other factors, the operator's body is thrown into motion, leading to repeated, unintended actions such as pressing and releasing the pedals, sometimes resulting in fluctuations in the amount of operation. In traditional excavators, these fluctuations in operation cause changes in the pressure of the hydraulic oil pumped out. Consequently, the machine shakes further, increasing the load on the operator.

[0160] Therefore, given the above circumstances, it is desirable to reduce the driver's workload.

[0161] like Figure 1 As shown, the excavator 100 according to this embodiment includes: a lower traveling body 1; an upper slewing body 3, which is rotatably mounted on the lower traveling body 1 via a slewing mechanism 2; a boom 4, a stick 5, and a bucket 6 constituting an auxiliary device AT; and a cab 10.

[0162] As described later, the lower traveling body 1 (an example of a traveling body) includes a pair of tracks 1C, specifically a left track 1CL and a right track 1CR. The lower traveling body 1 moves the excavator 100 by hydraulically driving the left track 1CL and the right track 1CR respectively by travel hydraulic motors 2M (left travel hydraulic motor 2ML and right travel hydraulic motor 2MR).

[0163] The upper rotating body 3 (an example of a rotating body) rotates relative to the lower traveling body 1 by being driven by a rotary hydraulic motor 2A.

[0164] The boom 4 is pivotally mounted at the front center of the upper slewing body 3. The stick 5 is pivotally mounted at the front end of the boom 4, which can rotate up and down. The bucket 6, which serves as an end attachment, is pivotally mounted at the front end of the stick 5, which can rotate up and down. The boom 4, stick 5, and bucket 6 are hydraulically driven by the boom cylinder 7, stick cylinder 8, and bucket cylinder 9, which are respectively hydraulic actuators.

[0165] In addition, the bucket 6 is an example of an end-connection device. Other end-connection devices (e.g., slope bucket, dredging bucket, breaker, etc.) can be installed at the front end of the boom 5 to replace the bucket 6, depending on the work content, etc.

[0166] The driver's cab 10 is the cockpit for the operator and is located on the front left side of the upper rotating body 3.

[0167] The excavator 100 operates the actuators according to the operation of the operator sitting in the cab 10, thereby driving the moving parts (driven parts) such as the lower walking body 1, the upper slewing body 3, the boom 4, the stick 5 and the bucket 6.

[0168] Furthermore, the excavator 100 can be configured to be operated by a driver in the cab 10, or, in addition to being configured to be operated by a driver in the cab 10, to be remotely operated by an operator of a specified external device (e.g., a support device or a management device).

[0169] At this time, the excavator 100 may, for example, send the image information (camera image) output by the spatial recognition device 70 (described later) to an external device. Furthermore, various information images (e.g., various setting screens) displayed on the display device D1 of the excavator 100 (described later) may also be displayed on the display device D1 located on the external device.

[0170] Therefore, the operator can, for example, remotely operate the excavator 100 while confirming the content displayed on the display device D1 located on the external device. Furthermore, the excavator 100 can also activate the actuators based on the remote operation signal received from the external device, which indicates the remote operation content, thereby driving the movement components such as the lower traveling body 1, the upper slewing body 3, the boom 4, the stick 5, and the bucket 6.

[0171] In this embodiment, the display device D1 is connected to the controller 30 (control unit). Under the control of the controller 30, it is positioned in a location easily visible from the driver's side inside the driver's cab 10 and displays various information images. The display device D1 is, for example, a liquid crystal display or an organic EL (Electroluminescence) display.

[0172] The spatial recognition device 70 of this embodiment includes a front sensor 70F installed at the front end of the upper surface of the cab 10, a rear sensor 70B installed at the rear end of the upper surface of the upper rotating body 3, a left sensor 70L installed at the left end of the upper surface of the upper rotating body 3, and a right sensor 70R installed at the right end of the upper surface of the upper rotating body 3. Furthermore, an upper recognition sensor for identifying objects existing in the space above the upper rotating body 3 can also be installed on the excavator 100.

[0173] The spatial recognition device 70 can be configured to detect objects present around the excavator 100. Objects may include, for example, terrain shapes (slopes or pits), power lines, utility poles, people, animals, vehicles, construction machinery, buildings, walls, helmets, safety vests, work clothes, or prescribed markings on helmets. The spatial recognition device 70 can be configured to identify at least one of the following: object type, location, and shape. The spatial recognition device 70 can also be configured to distinguish between people and objects other than people. Furthermore, the spatial recognition device 70 can be configured to calculate the distance from the spatial recognition device 70 or the excavator 100 to the object identified by the spatial recognition device 70. The spatial recognition device 70 may be, for example, an ultrasonic sensor, millimeter-wave radar, a monocular camera, a stereo camera, a LiDAR, a distance image sensor, or an infrared sensor.

[0174] When the excavator 100 is remotely operated, the cab 10 can be unmanned. The following describes the operator's actions, including the driver of the cab 10's operation of the control device 26 (see reference). Figure 9 The description is based on at least one of the operation of the device and remote operation performed by the driver from an external device.

[0175] Furthermore, the excavator 100 can automatically operate the hydraulic actuators regardless of the operator's commands. Thus, the excavator 100 achieves the function of automatically operating at least some of its moving parts, such as the lower traveling body 1, upper slewing body 3, boom 4, stick 5, and bucket 6 (hereinafter referred to as "automatic operation function" or "equipment control function"). The automatic operation function may include the function of automatically operating moving parts (hydraulic actuators) other than the moving parts of the object being operated (hydraulic actuators) based on the operator's commands to the operating device 26 or remote operation (the so-called "semi-automatic operation function").

[0176] Furthermore, the automatic operation function may also include the function of automatically operating at least a portion of the multiple driven components (hydraulic actuators) without the driver's operation of the operating device 26 or through remote operation (the so-called "fully automatic operation function").

[0177] In the excavator 100, when the fully automatic operation function is active, the interior of the cab 10 can be unmanned. Furthermore, the automatic operation function may also include a function that allows the excavator 100 to recognize the gestures of personnel or others around the excavator 100 and to automatically operate at least a portion of multiple driven components (hydraulic actuators) based on the content of the recognized gestures ("gesture operation function").

[0178] Furthermore, the semi-automatic operation function, fully automatic operation function, and gesture operation function may include the following method: automatically determining the working content of the action elements (hydraulic actuators) of the automatically operating object according to pre-defined rules. Also, the semi-automatic operation function, fully automatic operation function, and gesture operation function may include the following method: the excavator 100 autonomously performs various judgments and autonomously determines the working content of the action elements (hydraulic actuators) of the automatically operating object based on its judgment results (the so-called "autonomous operation function").

[0179] Next, refer to Figure 9 The basic system of the excavator 100 in this embodiment will be described. Figure 9 This is a diagram illustrating a structural example of the basic system of the construction machinery involved in this embodiment.

[0180] exist Figure 9 The mechanical power transmission lines, working oil lines, pilot lines, and electrical control lines are represented by double lines, solid lines, dashed lines, and single-dot lines, respectively. (Regarding...) Figure 10 The same.

[0181] The basic system of the excavator 100 mainly includes an engine 11, a pump regulator 13, a main pump 14, a control pump 15, a control valve unit 17, an operating device 26, a solenoid valve 27, an output pressure sensor 28, an operating pressure sensor 29, a controller 30, a switch 31, a switch 32, a motor regulator 50, etc.

[0182] Engine 11 is the drive source for excavator 100. In this embodiment, engine 11 is, for example, a diesel engine that operates as an internal combustion engine to maintain a specified speed. The output shaft of engine 11 is connected to the input shafts of main pump 14 and control pump 15.

[0183] The main pump 14 is a device for supplying working oil to the control valve unit 17 via the working oil line, for example, a swashplate variable capacity hydraulic pump.

[0184] Pump regulator 13 is a device for controlling the discharge volume of main pump 14. In this embodiment, pump regulator 13 controls the discharge volume of main pump 14 by adjusting the swashplate deflection angle of main pump 14, for example, based on the discharge pressure of main pump 14 and the command current from controller 30.

[0185] The control pump 15 is a device that supplies working oil to various hydraulic control devices including the operating device 26, such as a fixed capacity hydraulic pump.

[0186] The control valve unit 17 is a hydraulic control device for controlling the hydraulic system in the excavator 100.

[0187] Specifically, the control valve unit 17 includes a plurality of control valves that control the flow of working oil discharged from the main pump 14. Furthermore, the control valve unit 17 selectively supplies the working oil discharged from the main pump 14 to one or more hydraulic actuators via these control valves. These control valves control the flow rate of working oil from the main pump 14 to the hydraulic actuators and the flow rate of working oil from the hydraulic actuators to the working oil reservoir.

[0188] The hydraulic actuators include boom cylinder 7, stick cylinder 8, bucket cylinder 9, travel hydraulic motor 2M, and swing hydraulic motor 2A. The travel hydraulic motor 2M includes a left travel hydraulic motor 2ML and a right travel hydraulic motor 2MR.

[0189] The operating device 26 is a device for the driver to operate the hydraulic actuators. In this embodiment, the operating device 26 is hydraulic, and the working oil discharged by the control pump 15 is supplied via pilot lines to the pilot ports of the control valves corresponding to each hydraulic actuator.

[0190] Furthermore, the operating device 26 in this embodiment is primarily a pedal operated by the driver's foot. Alternatively, the operating device 26 may also include a lever operated by the driver's hand.

[0191] The pressure of the working oil supplied to each pilot port (hereinafter referred to as "pilot pressure") is the pressure corresponding to the operating direction and operating amount of the lever or pedal constituting the operating device 26 corresponding to each hydraulic actuator. However, the operating device 26 may also be electrically powered.

[0192] Solenoid valve 27 is disposed in pipeline C0 between control pump 15 and motor regulator 50. In this embodiment, solenoid valve 27 is an electromagnetic switching valve that switches the connection and disconnection of pipeline C0, and operates according to instructions from controller 30.

[0193] Pressure reducing valve 33 is disposed in the pipeline between control pump 15 and operating device 26 and solenoid valve 27. In this embodiment, pressure reducing valve 33 is a valve that reduces pilot pressure and operates according to instructions from controller 30.

[0194] The discharge pressure sensor 28 is a sensor used to detect the discharge pressure of the main pump 14 and outputs the detected value to the controller 30.

[0195] The operating pressure sensor 29 detects the operation of the driver using the operating device 26. In this embodiment, the operating pressure sensor 29 is, for example, a pressure sensor that detects the operating direction and amount of the pedals of the operating device 26 corresponding to each hydraulic actuator in the form of pressure, and outputs the detected value to the controller 30.

[0196] The operation of the operating device 26 can be detected using the outputs of devices other than pressure sensors, such as operating angle sensors, acceleration sensors, angular velocity sensors, rotary transformers, voltmeters, and ammeters. That is, the operation quantity of the operating device 26 can be represented not only by operating pressure, but also by operating angle, the double integral value of operating acceleration, the integral value of operating angular velocity, voltage values, current values, etc.

[0197] The controller 30 is a control device for controlling the excavator 100. In this embodiment, the controller 30 is, for example, a computer equipped with a CPU, volatile memory, non-volatile memory, etc. The controller 30, for example, causes the CPU to execute programs corresponding to the various functional requirements described later.

[0198] The controller 30 performs various processes described later, for example, based on the outputs of the discharge pressure sensor 28, the operating pressure sensor 29, the switch 31, etc. Details of the functions of the controller 30 will be described later.

[0199] Switch 31 is used to switch the operating mode (travel mode) of the motor regulator 50. In this embodiment, switch 31 is a software switch displayed on an in-vehicle display with a touch panel. Switch 31 may also be a hardware switch located in the driver's cab 10.

[0200] Switch 32 is used to switch between raising and lowering the cab 10. Switch 32 can be, for example, a hardware switch located within the cab 10, and it switches the raising and lowering of the cab 10 according to the operation. Furthermore, in this embodiment, the position of the cab 10 does not move when switch 32 is not operated.

[0201] Motor regulator 50 controls the motor volume of the travel hydraulic motor 2M. In this embodiment, motor regulator 50 includes a left motor regulator 50L and a right motor regulator 50R. The left motor regulator 50L adjusts the swashplate deflection angle of the left travel hydraulic motor 2ML according to the control pressure generated by the working oil supplied through solenoid valve 27, thereby controlling the motor volume of the left travel hydraulic motor 2ML. The same applies to the right motor regulator 50R.

[0202] Specifically, the left motor adjuster 50L switches between two stages: the swashplate deflection angle of the left travel hydraulic motor 2ML and the high rotation setting and the low rotation setting of the motor capacity of the left travel hydraulic motor 2ML.

[0203] The low-rotation setting is achieved by increasing the motor volume. In this setting, the left travel hydraulic motor 2ML operates at low rotation and high torque. The high-rotation setting is achieved by decreasing the motor volume. In this setting, the left travel hydraulic motor 2ML operates at high rotation and low torque. The same applies to the right motor regulator 50R.

[0204] The functions of the controller 30 in this embodiment will be described below. The controller 30 in this embodiment includes a fluctuation determination unit 301, a counting unit 302, a driving force change unit 303, and a storage unit 304.

[0205] The fluctuation determination unit 301 determines whether a fluctuation has occurred in the operating quantity based on the change in the operating quantity detected by the operating pressure sensor 29. In the case where the operating device 26 is electrically operated, the fluctuation can be determined based on the change in the operating angle.

[0206] Specifically, when a periodic increase or decrease is detected in the operating quantity detected by the operating pressure sensor 29, the fluctuation determination unit 301 determines that a fluctuation has occurred. Details of the fluctuation will be described later.

[0207] The counting unit 302 counts the number of times that the fluctuation determination unit 301 determines have occurred within a specified period and maintains the count value. Furthermore, the counting unit 302 resets the count value each time the specified period elapses. The specified period is a pre-set period.

[0208] The drive force changing unit 303 changes the drive force of the travel hydraulic motor 2M based on the number of fluctuations counted by the counting unit 302 within a specified period.

[0209] Specifically, the drive force change unit 303 refers to the information stored in the storage unit 304 that establishes a corresponding association between the number of fluctuations and the method of changing the drive force of the travel hydraulic motor 2M, and changes the drive force according to the number of fluctuations. In the following description, the information stored in the storage unit 304 will sometimes be described as corresponding association information.

[0210] In other words, the driving force of the walking hydraulic motor 2M in this embodiment is the driving pressure of the walking hydraulic motor 2M.

[0211] In this embodiment, the driving pressure of the walking hydraulic motor 2M can be set to, for example, the maximum output of the main pump 14. In other words, the maximum output of the main pump 14 is the maximum displacement of the main pump 14.

[0212] Furthermore, the driving pressure of the travel hydraulic motor 2M in this embodiment can also be set to the driving pressure of the travel hydraulic motor 2M. In other words, the driving pressure of the travel hydraulic motor 2M is the maximum displacement of the travel hydraulic motor 2M, and is controlled by adjusting the swashplate deflection angle of the travel hydraulic motor 2M by the motor regulator 50.

[0213] In this embodiment, the drive force changing unit 303 refers to the count value and corresponding associated information held by the counting unit 302, and decreases or increases the maximum value of the discharge volume of the main pump 14 based on the number of fluctuations generated within a specified period. In other words, the drive force changing unit 303 decreases or increases the maximum displacement of the main pump 14 or the travel hydraulic motor 2M based on the number of fluctuations generated within a specified period. In this way, the drive force changing unit 303 suppresses the pressure fluctuation of the working oil discharged by the main pump 14 by decreasing or increasing the maximum displacement of the main pump 14 or the travel hydraulic motor 2M.

[0214] Furthermore, an example is shown where the drive force change unit 303 controls the main pump 14 or the travel hydraulic motor 2M based on the determination result of the fluctuation determination unit 301, but it is not necessarily limited to this. For example, if an operating control valve (proportional valve) that operates based on an electrical signal from the controller 30 is arranged between the control pump 15 and the pilot port of the control valve, the drive force change unit 303 can control the operating control valve based on the determination result of the fluctuation determination unit 301.

[0215] Furthermore, when using an electromagnetic solenoid spool valve as a control valve, the drive force changing unit 303 can control the electromagnetic solenoid spool valve based on the determination result of the fluctuation determination unit 301. Thus, even when using an operating control valve, an electromagnetic solenoid spool valve, or the like, the drive force of the travel hydraulic motor can be changed.

[0216] In this embodiment, the storage unit 304 stores corresponding associated information in advance. Specifically, the associated information may be, for example, information indicating the discharge volume of the main pump 14 relative to a decrease or increase in a single fluctuation. Furthermore, the associated information may be, for example, information indicating the maximum displacement of the travel hydraulic motor 2M relative to a decrease or increase in a single fluctuation.

[0217] Furthermore, the corresponding correlation information can be a function representing the relationship between the number of fluctuations and the maximum output of the main pump 14. Also, the corresponding correlation information can be a function representing the relationship between the number of fluctuations and the maximum displacement of the travel hydraulic motor 2M.

[0218] Next, refer to Figure 10 The hydraulic system installed on the excavator 100 will be described. Figure 10 It means that it is carried on Figure 1 A schematic diagram of the hydraulic system of an excavator. Figure 10 In the hydraulic system, working oil is circulated from the left main pump 14L and right main pump 14R, driven by engine 11, through the left intermediate bypass line 40L, right intermediate bypass line 40R, left parallel line 42L, and right parallel line 42R to the working oil tank. The left main pump 14L and right main pump 14R... Figure 9 The main pump 14 corresponds to this.

[0219] The left middle bypass line 40L is the working oil line for control valves 172L, 177, 173, 175L and 176L, which are configured in control valve unit 17. The right middle bypass line 40R is the working oil line for control valves 171, 172R, 174, 175R and 176R, which are configured in control valve unit 17.

[0220] The control valve 172L is a slide valve that switches the flow of working oil by supplying working oil discharged from the left main pump 14L to the left travel hydraulic motor 2ML and discharging working oil discharged from the left travel hydraulic motor 2ML to the working oil tank.

[0221] Control valve 171 is a spool valve that functions as a straight-line travel valve. To improve the straight-line travel of the lower traveling body 1, control valve 171 switches the flow of working oil, supplying working oil from the left main pump 14L to both the left travel hydraulic motor 2ML and the right travel hydraulic motor 2MR. Specifically, when the travel hydraulic motor 2M and another hydraulic actuator are simultaneously operated, control valve 171 switches so that the left main pump 14L can supply working oil to both the left travel hydraulic motor 2ML and the right travel hydraulic motor 2MR. When no other hydraulic actuators are operated, control valve 171 switches so that the left main pump 14L can supply working oil to the left travel hydraulic motor 2ML and the right main pump 14R can supply working oil to the right travel hydraulic motor 2MR.

[0222] Control valve 177 is a spool valve that switches the flow of working oil by supplying working oil discharged from the left main pump 14L to an optional hydraulic actuator and discharging working oil discharged from the optional hydraulic actuator to a working oil tank. An optional hydraulic actuator may be, for example, a grab opening / closing cylinder.

[0223] Control valve 172R is a slide valve used to switch the flow of working oil by supplying working oil discharged from the right main pump 14R to the right travel hydraulic motor 2MR and discharging working oil discharged from the right travel hydraulic motor 2MR to the working oil tank.

[0224] Control valve 173 is a spool valve that switches the flow of working oil by supplying working oil discharged from the left main pump 14L to the rotary hydraulic motor 2A and discharging working oil discharged from the rotary hydraulic motor 2A to the working oil tank.

[0225] Control valve 174 is a slide valve used to supply working oil discharged by the right main pump 14R to the bucket cylinder 9 and to discharge working oil in the bucket cylinder 9 to the working oil tank.

[0226] Control valves 175L and 175R are slide valves used to switch the flow of working oil, supplying the working oil discharged from the left main pump 14L and the right main pump 14R to the boom cylinder 7 and discharging the working oil in the boom cylinder 7 to the working oil tank. In this embodiment, control valve 175L only operates when the boom 4 is raised, and does not operate when the boom 4 is lowered.

[0227] Control valves 175L and 175R are slide valves used to switch the flow of working oil by supplying the working oil discharged from the left main pump 14L and the right main pump 14R to the boom cylinder 8 and discharging the working oil in the boom cylinder 8 to the working oil tank.

[0228] The left parallel line 42L is a working oil line connected in parallel with the left intermediate bypass line 40L. When the flow of working oil through the left intermediate bypass line 40L is restricted or cut off by one of the control valves 172L, 177, 173, or 175L, the left parallel line 42L can supply working oil to a more downstream control valve. The right parallel line 42R is a working oil line connected in parallel with the right intermediate bypass line 40R. When the flow of working oil through the right intermediate bypass line 40R is restricted or cut off by one of the control valves 172R, 174, or 175R, the right parallel line 42R can supply working oil to a more downstream control valve.

[0229] The left pump regulator 13L and the right pump regulator 13R control the discharge volume of the left main pump 14L and the right main pump 14R by adjusting the swashplate deflection angle of the left main pump 14L and the right main pump 14R according to the discharge pressure of the left main pump 14L and the right main pump 14R. The left pump regulator 13L and the right pump regulator 13R... Figure 9 The pump regulator 13 corresponds to this. For example, when the discharge pressure of the left main pump 14L and the right main pump 14R increases, the left pump regulator 13L and the right pump regulator 13R adjust the swashplate deflection angle of the left main pump 14L and the right main pump 14R to reduce the discharge volume. This is to ensure that the absorbed horsepower of the main pump 14, which is represented by the product of the discharge pressure and the discharge volume, does not exceed the output horsepower of the engine 11.

[0230] Left travel operating device 26PL and right travel operating device 26PR are examples of operating device 26. Left travel operating device 26PL is a pedal device used to operate left travel hydraulic motor 2ML. Left travel operating device 26PL uses working oil discharged by control pump 15 to apply pilot pressure corresponding to the operating amount to the pilot port of control valve 172L. Specifically, when left travel operating device 26PL is operated in the forward direction, pilot pressure is applied to the left pilot port of control valve 172L; when left travel operating device 26PL is operated in the reverse direction, pilot pressure is applied to the right pilot port of control valve 172L.

[0231] The left-moving operating device 26PL has lifting pins 91L and 92L, which are fixed and supported on the floor and move up and down in conjunction with the rotation of a rotatable rotating body. The lifting pins 91L and 92L are each subjected to upward force by springs or the like. For example, when the left-moving operating device 26PL is operated in the forward direction, the front end of the lifting pin 91L presses down on the remote control valve 93L; when the left-moving operating device 26PL is operated in the backward direction, the front end of the lifting pin 92L presses down on the remote control valve 94L.

[0232] The right-travel operating device 26PR is used to operate the right-travel hydraulic motor 2MR. The right-travel operating device 26PR utilizes the working oil discharged from the control pump 15 to apply a pilot pressure corresponding to the operating amount to the pilot port of the control valve 172R. Specifically, when the right-travel operating device 26PR is operated in the forward direction, the pilot pressure is applied to the right pilot port of the control valve 172R; when the right-travel operating device 26PR is operated in the reverse direction, the pilot pressure is applied to the left pilot port of the control valve 172R.

[0233] The right-walking operating device 26PR has lifting pins 91R and 92R, which are fixed and supported on the floor and move up and down in conjunction with the rotation of a rotatable rotating body. The lifting pins 91R and 92R are each subjected to upward force by springs or the like. For example, when the right-walking operating device 26PR is operated in the forward direction, the front end of the lifting pin 91R presses down on the remote control valve 93R; when the right-walking operating device 26PR is operated in the backward direction, the front end of the lifting pin 92R presses down on the remote control valve 94R.

[0234] When solenoid valve 27 receives a connection command from controller 30, it connects control pump 15 to motor regulator 50. At this time, motor regulator 50 operates in a forced fixed mode. Conversely, when solenoid valve 27 does not receive a connection command from controller 30, it disconnects control pump 15 from motor regulator 50. At this time, motor regulator 50 operates in a variable mode.

[0235] The pressure reducing valve 33 controls the stroke (movement) of the valve cores of each control valve 172L and 172R according to instructions from the controller 30. In this embodiment, the pressure reducing valve 33 is not necessarily required when performing flow reduction processing based on the travel hydraulic motor 2M, main pump 14, engine 11, etc.

[0236] The discharge pressure sensors 28L and 28R are Figure 9 An example of discharge pressure sensor 28. Discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L and outputs the detected value to controller 30. Discharge pressure sensor 28R detects the discharge pressure of the right main pump 14R and outputs the detected value to controller 30.

[0237] Operating pressure sensors 29L and 29R are Figure 9 An example of the operating pressure sensor 29. Specifically, operating pressure sensors 29L and 29R are examples of detection mechanisms for detecting the operating status of the travel control device. Operating pressure sensor 29L detects the driver's operation on the left travel control device 26PL in the form of pressure and outputs the detected value to controller 30. Operating pressure sensor 29R detects the driver's operation on the right travel control device 26PR in the form of pressure and outputs the detected value to controller 30.

[0238] Furthermore, the operating devices 26 (left travel operating device 26PL, right travel operating device 26PR, left travel lever 26DL, and right travel lever 26DR, etc.) can be electrically operated, outputting an electrical signal (hereinafter referred to as "operation signal"), rather than hydraulically piloted, outputting pilot pressure. In this case, the electrical signal (operation signal) from the operating device 26 is input to the controller 30, which controls each of the control valves 171 to 177 within the control valve unit 17 according to the input electrical signal, thereby enabling the operation of various hydraulic actuators corresponding to the operation of the operating device 26. For example, the control valves 171 to 177 within the control valve unit 17 can be electromagnetic solenoid spool valves driven by commands from the controller 30. Furthermore, for example, a hydraulic control valve (hereinafter referred to as "operation control valve") that operates according to the electrical signal from the controller 30 can be arranged between the control pump 15 and the pilot port of each control valve 171 to 177. The operation control valve can be, for example, a proportional valve. At this time, if manual operation is performed using the electric operating device 26, the controller 30 controls the operating control valve and increases or decreases the pilot pressure according to the electrical signal corresponding to its operating amount (e.g., lever operating amount), so that each control valve 171 to 177 can be operated according to the operation content of the operating device 26.

[0239] The boom control lever, stick control lever, bucket control lever, and swing control lever (not shown) are respectively the operating devices for operating the up and down rotation of the boom 4, the opening and closing of the stick 5, the opening and closing of the bucket 6, and the rotation of the upper slewing body 3. These operating devices, like the left travel control device 26PL, utilize the working oil discharged by the control pump 15 to apply pilot pressure corresponding to the lever operation amount to one of the left or right pilot ports of the control valve corresponding to each hydraulic actuator. Furthermore, the operator's operation of these operating devices is detected in pressure form by the corresponding operating pressure sensor, similar to the operating pressure sensor 29L, and the detected value is output to the controller 30.

[0240] Here, regarding Figure 10 The negative control method used in the hydraulic system will be explained.

[0241] The left intermediate bypass line 40L and the right intermediate bypass line 40R are equipped with a left throttle valve 18L and a right throttle valve 18R between the downstream control valves 176L and 176R and the working oil tank. The flow of working oil discharged by the left main pump 14L and the right main pump 14R is restricted by the left throttle valve 18L and the right throttle valve 18R. Furthermore, the left throttle valve 18L and the right throttle valve 18R generate control pressures for controlling the left pump regulator 13L and the right pump regulator 13R.

[0242] The left control pressure sensor 19L and the right control pressure sensor 19R are sensors that detect the control pressure generated upstream of the left throttle 18L and the right throttle 18R, respectively. In this embodiment, the left control pressure sensor 19L and the right control pressure sensor 19R output the detected values ​​to the controller 30.

[0243] The controller 30 outputs commands corresponding to the control pressure to the left pump regulator 13L and the right pump regulator 13R. The left pump regulator 13L and the right pump regulator 13R control the output of the left main pump 14L and the right main pump 14R by adjusting the swashplate deflection angle of the left main pump 14L and the right main pump 14R according to the commands. Specifically, the left pump regulator 13L and the right pump regulator 13R are configured such that: the higher the control pressure, the lower the output of the left main pump 14L and the right main pump 14R; and the lower the control pressure, the higher the output of the left main pump 14L and the right main pump 14R.

[0244] With neither hydraulic actuator in operation, the working oil discharged from the left main pump 14L and the right main pump 14R reaches the left throttle 18L and the right throttle 18R through the left intermediate bypass line 40L and the right intermediate bypass line 40R. Furthermore, the flow of the working oil discharged from the left main pump 14L and the right main pump 14R increases the control pressure upstream of the left throttle 18L and the right throttle 18R. As a result, the left pump regulator 13L and the right pump regulator 13R reduce the discharge volume of the left main pump 14L and the right main pump 14R to the minimum permissible discharge volume, suppressing pressure loss (pumping loss) of the discharged working oil as it passes through the left intermediate bypass line 40L and the right intermediate bypass line 40R.

[0245] On the other hand, when a particular hydraulic actuator is operated, the working oil discharged from the left main pump 14L and the right main pump 14R flows into the hydraulic actuator of the target hydraulic actuator via the control valve corresponding to the target hydraulic actuator. Furthermore, the flow of working oil discharged from the left main pump 14L and the right main pump 14R reduces or eliminates the amount reaching the left throttle valve 18L and the right throttle valve 18R, thereby reducing the control pressure generated upstream of the left throttle valve 18L and the right throttle valve 18R. As a result, the left pump regulator 13L and the right pump regulator 13R increase the discharge volume of the left main pump 14L and the right main pump 14R, ensuring sufficient working oil circulation to the target hydraulic actuator, thereby guaranteeing the drive of the target hydraulic actuator.

[0246] With the structure described above, even when the hydraulic actuators are not operated... Figure 10 The hydraulic system can suppress unnecessary energy consumption in the left main pump 14L and right main pump 14R. Unnecessary energy consumption includes pumping losses caused by the working oil discharged from the left main pump 14L and right main pump 14R in the left intermediate bypass line 40L and right intermediate bypass line 40R. When operating the hydraulic actuator, a sufficient amount of working oil can be reliably supplied from the left main pump 14L and right main pump 14R to the hydraulic actuator of the workpiece.

[0247] Next, refer to Figure 11A and Figure 11B The fluctuations and corresponding related information in this embodiment are explained. Figure 11A and Figure 11B It is a diagram illustrating fluctuations and their corresponding related information.

[0248] Figure 11A This indicates the relationship between the changes in the operating quantity detected by the operating pressure sensor 29, the number of fluctuations, and the driving force of the travel hydraulic motor 2M. Additionally, in Figure 11A In the example, the operating quantity detected by the operating pressure sensor 29 is set as the pilot pressure, and the driving force of the walking hydraulic motor 2M is set as the maximum displacement of the main pump 14.

[0249] In this embodiment, when the fluctuation range of the pilot pressure is a specified value and the period of the pilot pressure fluctuation is a specified interval, it is determined that the operation quantity has fluctuated.

[0250] exist Figure 11A In the example, the interval from time T1 to time T2 is a predetermined interval, and the fluctuation range of the leader pressure during this period is a predetermined value. Therefore, the period from time T1 to time T2 is counted as one fluctuation. That is, in this embodiment, the amplitude (fluctuation range) of the waveform representing the leader pressure is a predetermined value, and when the predetermined interval is taken as a period, one period is counted as one fluctuation.

[0251] Furthermore, in Figure 11A In the specified interval from time T2 to time T3, the fluctuation range of the pilot pressure also becomes a specified value, so the number of fluctuations generated during the period from time T1 to time T3 becomes two.

[0252] In this embodiment, the maximum displacement of the main pump 14 is set to a value corresponding to the number of fluctuations.

[0253] Figure 11B This diagram illustrates an example of the corresponding associated information stored in storage unit 304. Figure 11B In the example, as the corresponding association information, it is set as information that establishes a corresponding association between the number of fluctuations within a specified period and the maximum displacement of the main pump 14.

[0254] In addition, Figure 11B In this example, the specified period is set to 1 second, and the counting unit 302 maintains the number of fluctuations detected by the fluctuation determination unit 301 as a count value every 1 second. Therefore, the count value of the counting unit 302 is reset every 1 second.

[0255] When the number of fluctuations is two, the driving force change unit 303 references... Figure 11B Based on the corresponding associated information, the maximum displacement of the main pump 14 is set to the value after reducing the displacement by the equivalent of two fluctuations.

[0256] Next, refer to Figure 12 The operation of the excavator 100 in this embodiment will be explained. Figure 12 This is a flowchart illustrating the operation of an excavator.

[0257] In this embodiment, the excavator 100 is determined by the fluctuation determination unit 301 of the controller 30 to determine whether fluctuation has occurred (step S501). In step S501, if no fluctuation is detected, the controller 30 proceeds to step S505, which will be described later.

[0258] In step S501, when fluctuations are detected, the controller 30 counts the number of fluctuations within a specified period using the counting unit 302 and maintains the count value (step S502).

[0259] Next, the controller 30 refers to the corresponding associated information in the storage unit 304 through the drive force change unit 303, and changes the drive force of the walking hydraulic motor 2M according to the count value (step S503).

[0260] Next, the controller 30 resets the count value through the counting unit 302 (step S504) and determines whether the engine 11 of the excavator 100 has stopped (step S505).

[0261] In step S505, if the engine 11 has not stopped, the controller 30 returns to step S501. In step S505, if the engine has stopped, the controller 30 terminates the process.

[0262] Here, for reference Figure 11B The processing performed by the driving force change unit 303 in step S503 will be explained in detail.

[0263] In this embodiment, for example, two fluctuations are detected within one second, which is the initial predetermined period during which processing begins by the controller 30. At this time, the count value of the counting unit 302 becomes "2". Figure 11B In the corresponding association information shown, the maximum displacement of the main pump 14 corresponding to the count value "2" is P1. Therefore, the drive force change unit 303 reduces the maximum displacement of the main pump 14 to P1 and resets the count value "2".

[0264] The controller 30 detects a fluctuation within one second, which is the next specified period. At this time, the count value of the counter unit 302 becomes "1". Figure 11B In the corresponding association information shown, the maximum displacement of the main pump 14 corresponding to the count value "1" is P2. Therefore, the drive force change unit 303 increases the maximum displacement of the main pump 14 from the current value P1 to the value P2, and resets the count value "1".

[0265] Thus, the drive force change unit 303 of this embodiment counts the number of fluctuations generated during each specified period, so that the maximum displacement of the main pump 14 becomes the value corresponding to the count value.

[0266] That is, in this embodiment, when the fluctuation continues, the count value increases, and the maximum displacement of the main pump 14 decreases. In other words, when the fluctuation continues, the drive force changing unit 303 reduces the drive force of the travel hydraulic motor 2M. Furthermore, in this embodiment, when the fluctuation converges, the count value decreases, and the maximum displacement of the main pump 14 increases. In other words, when the operating amount does not fluctuate, the drive force of the travel hydraulic motor 2M returns to its original state.

[0267] In this embodiment, the more fluctuations are detected, the lower the driving force of the travel hydraulic motor 2M becomes. Therefore, even in the event of unexpected operation, the change in load on the travel hydraulic motor 2M can be less than the change in the operating amount. In other words, even in the event of unexpected operation, the driving force changing unit 303 can suppress the pressure fluctuation of the working oil discharged by the main pump 14.

[0268] If the load variation on the walking hydraulic motor 2M decreases, the swaying amplitude during walking (walking action) also decreases, thus allowing the driver to support their body and reduce fluctuations in the amount of operation on the walking control device. In the above embodiment, the presence or absence of fluctuations is determined based on the output waveform of the operation amount, but this is not necessarily the case. In particular, the walking action is a standalone action, not a combined action with other hydraulic actuators. Therefore, changes in the output of the walking operation amount also affect the detection value of the discharge pressure sensor 28 and the motor drive pressure.

[0269] In this embodiment, the presence or absence of fluctuations can also be determined based on the detection values ​​(output waveforms) detected in the walking drive system from the operating device 26 to the walking hydraulic motor 2M. For example, the presence or absence of fluctuations in the operating amount can also be determined based on the detection values ​​(output waveforms) of the motor drive pressure. Furthermore, the presence or absence of fluctuations in the operating amount can also be determined based on the detection values ​​(output waveforms) of the discharge pressure sensor 28.

[0270] The following is for reference. Figure 13A and Figure 13B The effects of this implementation method will be explained. Figure 13A This is a waveform diagram showing the pilot pressure and the drive pressure of the travel hydraulic motor 2M when fluctuations occur in an excavator that is not applicable to this embodiment. Figure 13B It is a waveform diagram showing the pilot pressure, the number of fluctuations, and the driving pressure of the travel hydraulic motor 2M when fluctuations occur in the excavator 100 of this embodiment.

[0271] exist Figure 13BIn this process, since a fluctuation is detected at time t1, the drive force changing unit 303 reduces the drive pressure of the travel hydraulic motor 2M by the amount of one fluctuation. However, in this state, the pilot pressure fluctuates periodically, and a fluctuation is also detected at time t2. Therefore, the drive force changing unit 303 further reduces the drive pressure of the travel hydraulic motor 2M by the amount of one fluctuation.

[0272] In this state, since the pilot pressure still fluctuates periodically, a fluctuation is also detected at time t3. Therefore, the drive force change unit 303 further reduces the amount of one fluctuation in the drive pressure of the travel hydraulic motor 2M.

[0273] In this state, the pilot pressure still fluctuates periodically, and a fluctuation is detected at time t4. Therefore, the drive force change unit 303 further reduces the amount of one fluctuation in the drive pressure of the travel hydraulic motor 2M.

[0274] At this moment t4, the driving pressure of the travel hydraulic motor 2M is sufficiently reduced. Therefore, even assuming that the pilot pressure changes due to an unexpected operation by the driver, the fluctuation of the driving pressure of the travel hydraulic motor 2M can be suppressed, and the fluctuation of the operation amount can be easily converged.

[0275] In contrast, Figure 13A As can be seen from the example, if a fluctuation occurs, the movement continues while the fluctuation is ongoing.

[0276] Thus, according to this embodiment, even when fluctuations in the amount of operation occur, the fluctuations can be quickly contained, which can reduce the severity of the poor riding comfort caused by the shaking of the aircraft body and the driver fatigue caused by the shaking of the body, thereby reducing the driver's load.

[0277] Furthermore, according to this embodiment, fluctuations can be quickly contained, thus enabling the excavator 100 to quickly return to a stable walking state and effectively travel to its destination. Also, according to this embodiment, fluctuations can be quickly contained, thus reducing damage to the machine body caused by continuous fluctuations.

[0278] Furthermore, while this embodiment describes the case where the driver primarily operates the pedals, it is not limited to this. This embodiment also applies to fluctuations in the amount of operation that occur when the driver performs lever operations.

[0279] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Various modifications and substitutions can be applied to the above embodiments without departing from the scope of the present invention. Furthermore, features described separately can be combined as long as they do not contradict each other technically.

[0280] For example, in the above embodiments, a hydraulic operating system with a hydraulic pilot circuit is disclosed. For instance, in the hydraulic pilot circuit associated with the left travel lever 26DL, working oil supplied from the control pump 15 to the left travel lever 26DL is supplied to the pilot port of the control valve 172L at a pressure corresponding to the opening of a remote control valve that actuates by tilting the left travel lever 26DL in the forward direction. Alternatively, in the hydraulic pilot circuit associated with the right travel lever 26DR, working oil supplied from the control pump 15 to the right travel lever 26DR is supplied to the pilot port of the control valve 172R at a pressure corresponding to the opening of a remote control valve that actuates by tilting the right travel lever 26DR in the forward direction.

[0281] However, an electrically operated operating system with an electric pilot circuit can be used instead of a hydraulically operated operating system with a hydraulic pilot circuit. In this case, the lever operation amount of the electrically operated lever in the electrically operated operating system is input to the controller 30 as an electrical signal, for example. Furthermore, a solenoid valve is arranged between the control pump 15 and the pilot port of each control valve. The solenoid valve is configured to operate according to the electrical signal from the controller 30. With this structure, if manual operation using the electrically operated lever is performed, the controller 30 controls the solenoid valve to increase or decrease the pilot pressure according to the electrical signal corresponding to the lever operation amount, thereby enabling the movement of each control valve. Alternatively, each control valve can be configured as a solenoid spool valve. In this case, the solenoid spool valve is electromagnetically operated according to the electrical signal from the controller 30 corresponding to the lever operation amount of the electrically operated lever.

[0282] When using an electric operating system with an electric joystick, the controller 30 can more easily perform autonomous control functions compared to a hydraulic operating system with a hydraulic joystick. Figure 14 This illustrates a structural example of an electrically powered operating system. Specifically, Figure 14 The electric operating system is an example of a left-travel operating system used to rotate the left-travel hydraulic motor 2ML. It mainly consists of a pilot pressure working type control valve unit 17, a left-travel lever 26DL which is an electric operating lever, a controller 30, a left forward solenoid valve 60 and a left backward solenoid valve 62. Figure 14 The electric operating system can also be applied to the slewing operating system for rotating the upper slewing body 3, the boom operating system for rotating the boom 4 up and down, the stick operating system for opening or closing the stick 5, and the bucket operating system for opening or closing the bucket 6, etc.

[0283] Pilot-operated control valve unit 17 includes a control valve 171 (reference) that functions as a travel valve. Figure 3 ), and the control valve 172L related to the left travel hydraulic motor 2ML (reference). Figure 3), and the control valve 172R related to the right travel hydraulic motor 2MR (reference). Figure 3 ), and control valve 173 related to rotary hydraulic motor 2A (see reference). Figure 3 ), and control valve 175 related to boom cylinder 7 (reference). Figure 3 ), and control valve 176 related to boom cylinder 8 (reference). Figure 3 ) and control valve 174 related to bucket cylinder 9 (see reference) Figure 3 Solenoid valve 60 is configured to regulate the pressure of the working oil in the pipeline connecting the control pump 15 and the forward pilot port of control valve 172L. Solenoid valve 62 is configured to regulate the pressure of the working oil in the pipeline connecting the control pump 15 and the reverse pilot port of control valve 172L.

[0284] In manual operation, the controller 30 generates a forward operation signal (electrical signal) or a backward operation signal (electrical signal) based on the operation signal (electrical signal) output by the operation signal generation unit of the left travel lever 26DL. The operation signal output by the operation signal generation unit of the left travel lever 26DL is an electrical signal that varies according to the operation amount and operation direction of the left travel lever 26DL.

[0285] Specifically, when the left travel lever 26DL is operated in the forward direction, the controller 30 outputs a forward operation signal (electrical signal) corresponding to the lever operation amount to the solenoid valve 60. The solenoid valve 60 operates according to the forward operation signal (electrical signal) and controls the pilot pressure acting on the forward side pilot port of the control valve 172L, which serves as the forward operation signal (pressure signal). Similarly, when the left travel lever 26DL is operated in the reverse direction, the controller 30 outputs a reverse operation signal (electrical signal) corresponding to the lever operation amount to the solenoid valve 62. The solenoid valve 62 operates according to the reverse operation signal (electrical signal) and controls the pilot pressure acting on the reverse side pilot port of the control valve 172L, which serves as the reverse operation signal (pressure signal).

[0286] When performing autonomous control, the controller 30 generates a forward operation signal (electrical signal) or a backward operation signal (electrical signal) for example, based on a correction operation signal (electrical signal) instead of the operation signal (electrical signal) output by the operation signal generation unit of the left travel stick 26DL. The correction operation signal can be an electrical signal generated by the controller 30, or an electrical signal generated by a control device other than the controller 30.

[0287] Furthermore, in the above embodiment, the excavator 100 is configured to allow the operator to sit inside the cab 10, but it can also be a remotely operated excavator. In this case, the operator can remotely operate the excavator 100, for example, using operating devices and communication devices located in a remote control room outside the work site. In this case, the controller 30 can also be installed in the remote control room. That is, the controller 30 installed in the remote control room and the excavator 100 can constitute an excavator system.

[0288] This application claims priority based on Japanese Patent Application No. 2021-056036, filed on March 29, 2021, and Japanese Patent Application No. 2021-061265, filed on March 31, 2021, the entire contents of which are incorporated herein by reference.

[0289] Explanation of symbols

[0290] 1-Lower traveling body, 1C-track, 1CL-left track, 1CR-right track, 2-slewing mechanism, 2A-slewing hydraulic motor, 2M-travel hydraulic motor, 2ML-left travel hydraulic motor, 2MR-right travel hydraulic motor, 3-Upper slewing body, 4-boom, 5-stick, 6-bucket, 7-boom cylinder, 8-stick cylinder, 9-bucket cylinder, 10-cab, 11-engine, 13-pump regulator, 14-main pump, 15- 17-Control pump, 18-Control valve unit, 19-Throttle, 26-Control pressure sensor, 26-Operating device, 26D-Travel lever, 26DL-Left travel lever, 26DR-Right travel lever, 26L-Left operating lever, 26R-Right operating lever, 28-Discharge pressure sensor, 29, 29DL, 29DR, 29LA, 29LB, 29RA, 29RB-Operating pressure sensors, 30-Controller, 30A-Setting unit. 30B - Autonomous Control Unit, 30C - Posture Detection Unit, 40 - Intermediate Bypass Pipeline, 42 - Parallel Pipeline, 50 - Motor Regulator, 50L - Left Motor Regulator, 50R - Right Motor Regulator, 60, 62 - Solenoid Valves, 70 - Spatial Recognition Device, 70F - Front Sensor, 70B - Rear Sensor, 70L - Left Side Sensor, 70R - Right Side Sensor, 71 - Orientation Detection Device, 72 - Information Input Device, 73 - Positioning Device, 100 - Excavator, 171-177 - Control Valves, 301 - Fluctuation Judgment Unit, 302 - Counting Unit, 303 - Drive Force Change Unit, 304 - Storage Unit, AT - Auxiliary Device, D1 - Display Device, D2 - Sound Output Device, S1 - Boom Angle Sensor, S2 - Stick Angle Sensor, S3 - Bucket Angle Sensor, S4 - Body Tilt Sensor, S5 - Swing Angular Velocity Sensor, SYS - Management System.

Claims

1. An excavator, comprising: The lower running gear, including tracks; The upper rotating body is rotatably mounted on the lower walking body; The walking hydraulic motor drives the tracks; A walking control device, corresponding to the walking hydraulic motor; The hydraulic pump supplies working oil to the travel hydraulic motor; and The testing organization checks the operating status of the walking operation device. The tracks have a left track and a right track. The walking operation device has a left walking operation device corresponding to the left track and a right walking operation device corresponding to the right track. The detection mechanism detects whether there is a predetermined difference between the operation amount of the left travel operating device and the operation amount of the right travel operating device. If there is a predetermined difference between the operation amount of the left travel operating device and the operation amount of the right travel operating device, in order to make the flow rate of the working oil discharged by the hydraulic pump vary within a predetermined range determined by the upper and lower limits, the change in the command value related to the flow rate of the working oil discharged by the hydraulic pump is suppressed.

2. The excavator according to claim 1, wherein, The detection mechanism detects whether the pilot pressure fluctuates. In the event of pilot pressure fluctuations, the variation in the flow rate of the working oil discharged by the hydraulic pump is suppressed.

3. The excavator according to claim 2, wherein, If there is a predetermined difference between the operation amount of the left travel operating device and the operation amount of the right travel operating device, it is determined that the lower travel body is moving forward on a curve, and the fluctuation of the flow rate of the working oil discharged by the hydraulic pump is suppressed.

4. The excavator according to claim 3, wherein, The specified difference is generated when the operating amount of one of the left-walking operating devices and the right-walking operating devices is increased, when the operating amount of one device is decreased, when the operating amounts of both devices are increased, or when the operating amounts of both devices are decreased.

5. The excavator according to claim 1, wherein, The amount of change in the command value related to the flow rate of the working oil discharged from the hydraulic pump is suppressed based on the pressure of the working oil flowing through the hydraulic circuit or the operation amount of the traveling operating device.

6. The excavator according to claim 5, wherein, At least one of an upper limit and a lower limit is set in the change amount of the instruction value.

7. The excavator according to claim 1, wherein, The hydraulic pump is an electrically controlled variable capacity hydraulic pump.

8. The excavator according to claim 1, wherein, The detection mechanism determines whether the amount of operation on the walking device fluctuates during the walking action. The control unit adjusts the driving force of the walking hydraulic motor based on the fluctuations.

9. The excavator according to claim 8, wherein, The control unit controls at least one of the main pump and the travel hydraulic motor based on the determination result.

10. The excavator according to claim 8, wherein, The control unit controls the operating control valve configured at the pilot port based on the determination result.

11. The excavator according to claim 8, wherein, The driving force is the maximum displacement of the main pump or the maximum displacement of the walking hydraulic motor.

12. The excavator according to claim 8, wherein, The changes in driving force performed by the control unit include both reducing and increasing the driving force.

13. The excavator according to claim 8, wherein, The walking operation device is a pedal device installed on the ground of the cockpit.

14. An excavator, comprising: The lower running gear, including tracks; The upper rotating body is rotatably mounted on the lower walking body; The walking hydraulic motor drives the tracks; A walking control device, corresponding to the walking hydraulic motor; The hydraulic pump supplies working oil to the travel hydraulic motor; The testing agency detects the operating status of the walking operation device and determines whether the amount of operation on the walking operation device fluctuates during the walking action. The counting unit counts the number of times the fluctuation is detected within a specified period; and The storage unit stores correlation information that establishes a corresponding association between the number of fluctuations and the method for changing the driving force of the walking hydraulic motor. The tracks have a left track and a right track. The walking operation device has a left walking operation device corresponding to the left track and a right walking operation device corresponding to the right track. The detection mechanism detects whether there is a predetermined difference between the operation amount of the left travel operating device and the operation amount of the right travel operating device. If there is a predetermined difference between the operation amounts of the left travel operating device and the right travel operating device, the mechanism suppresses the change in the command value related to the flow rate of the working oil discharged by the hydraulic pump. The driving force is changed by referring to the number of times the fluctuations are detected by the counting unit and the corresponding associated information.

15. The excavator according to claim 14, wherein, The counting unit resets the counted number of times for each of the specified periods.

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