JP2023150959A - Shovel - Google Patents

Abstract

To provide a technique for suppressing unstable behavior during operation to discharge storage materials from a bucket of a shovel to the outside.SOLUTION: A shovel 100 in one embodiment of this disclosure includes an undercarriage 1, a super structure 3, a boom 4, an arm 5, a bucket 6, a boom cylinder 7, an arm cylinder 8, a main pump 14, a control valve 17 for supplying working oil supplied from the main pump 14 to the boom cylinder 7 and the arm cylinder 8, a regeneration circuit 175La for regenerating the working oil discharged from the boom cylinder 7 for the arm cylinder 8 when the lowering operation of the boom 4 and the opening operation of the arm 5 are performed, and a control part 304 for making the regeneration flow amount to the arm cylinder 8 by the regeneration circuit 175La smaller than a predetermined reference state during operation to discharge storage materials from the bucket 6.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to excavators.

A technique for suppressing unstable behavior such as lifting of a shovel during excavation is known (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2014-122510

By the way, during the operation of discharging the contents (earth and sand, etc.) in the excavator bucket to the outside, unstable behavior such as tipping forward of the machine body (upper rotating body) or vibration may occur.

Therefore, in view of the above problems, it is an object of the present invention to provide a technique that can suppress unstable behavior during the operation of discharging the contents of the bucket of an excavator to the outside.

To achieve the above object, in one embodiment of the present disclosure,
a lower running body;
an upper rotating body rotatably mounted on the lower traveling body;
a boom attached to the upper revolving body;
an arm attached to the tip of the boom;
a bucket attached to the tip of the arm;
a boom cylinder that drives the boom;
an arm cylinder that drives the arm;
hydraulic pump and
a control valve that supplies hydraulic oil supplied from the hydraulic pump to the boom cylinder and the arm cylinder;
a regeneration circuit that regenerates hydraulic oil discharged from the boom cylinder into the arm cylinder when the boom is lowered and the arm is opened;
a control unit that makes the regeneration flow rate to the arm cylinder by the regeneration circuit smaller than a predetermined reference state during the operation of discharging the contents of the bucket;
A shovel will be provided.

According to the embodiment described above, unstable behavior can be suppressed during the operation of discharging the contents of the excavator bucket to the outside.

It is a side view showing an example of an excavator. FIG. 2 is a block diagram showing an example of the hardware configuration of an excavator. It is a diagram showing an example of a hydraulic circuit of a hydraulic drive system and an operation system of an excavator. It is a figure which shows an example of the control valve which drives a boom cylinder. It is a figure which shows an example of the control valve which drives a boom cylinder. It is a diagram showing an example of a hydraulic oil holding circuit. FIG. 2 is a functional block diagram showing an example of the functional configuration of an excavator. FIG. 3 is a diagram showing an example of a state of the shovel 100 immediately before an earth removal operation. FIG. 3 is a diagram showing an example of a display regarding the postural stability of an excavator. FIG. 7 is a diagram showing another example of a display regarding the postural stability of the excavator.

Embodiments will be described below with reference to the drawings.

[Excavator overview]
First, with reference to FIG. 1, an overview of the shovel 100 according to the present embodiment will be explained. Hereinafter, when the shovel 100 is viewed from above, the direction in which the attachment AT extends is referred to as "front", and the front, back, left, and right directions of the shovel 100 may be described.

FIG. 1 is a side view showing an example of a shovel 100.

As shown in FIG. 1, the excavator 100 includes a lower traveling body 1, an upper rotating body 3, an attachment AT including a boom 4, an arm 5, and a bucket 6, and a cabin 10.

The lower traveling body 1 includes, for example, a pair of left and right crawlers, and the left and right crawlers are hydraulically driven by corresponding travel hydraulic motors 1ML and 1MR (see FIG. 2), so that the lower traveling body 1 self-propels.

The upper rotating body 3 is rotatably mounted on the lower traveling body 1 via the rotating mechanism 2 . For example, the upper rotating structure 3 turns with respect to the lower traveling structure 1 by hydraulically driving the turning mechanism 2 by the turning hydraulic motor 2M.

The boom 4 is attached to the center of the front part of the upper revolving body 3 so as to be able to rise and fall about a rotation axis along the left-right direction. The arm 5 is attached to the tip of the boom 4 so as to be rotatable about a rotation axis extending in the left-right direction. The bucket 6 is attached to the tip of the arm 5 so as to be rotatable about a rotation axis extending in the left-right direction.

The bucket 6 (an example of an end attachment) is attached to the tip of the arm 5 in such a manner that it can be replaced as appropriate depending on the work content of the shovel 100.

Furthermore, instead of the bucket 6, a bucket of a different type than the bucket 6, such as a relatively large bucket, a slope bucket, a dredging bucket, etc., may be attached to the tip of the arm 5. Further, an end attachment of a type other than the bucket, such as an agitator, a breaker, a crusher, etc., may be attached to the tip of the arm 5. Furthermore, a preliminary attachment such as a quick coupling or a tiltrotator may be provided between the arm 5 and the end attachment.

The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively.

The cabin 10 is a control room for an operator to board and operate the shovel 100, and is mounted, for example, on the front left side of the upper revolving structure 3.

The excavator 100 operates driven elements such as the lower traveling body 1 (i.e., a pair of left and right crawlers), the upper revolving body 3, the boom 4, the arm 5, and the bucket 6 in response to operations by an operator riding in the cabin 10. let

Further, instead of being configured to be operable by an operator riding in the cabin 10, or in addition to being configured to be operable by an operator riding in the cabin 10, the shovel 100 may be configured to be remotely operated from outside the shovel 100. When the excavator 100 is remotely controlled, the interior of the cabin 10 may be unmanned. The following description will proceed on the premise that the operator's operations include at least one of an operator's operation on the operating device 26 by an operator in the cabin 10 and a remote control by an external operator.

The remote control includes, for example, a mode in which the shovel 100 is operated by an operation input regarding an actuator of the shovel 100 performed by a remote control support device.

The remote operation support device is provided, for example, in a management center that manages the work of the excavator 100 from the outside. Further, the remote operation support device may be a portable operation terminal, and in this case, the operator can remotely control the excavator 100 while directly checking the working status of the excavator 100 from around the excavator 100. .

The functions of the remote operation support device are realized by arbitrary hardware or a combination of arbitrary hardware and software. For example, a remote operation support device is mainly configured with a computer including a CPU (Central Processing Unit), a memory device, an auxiliary storage device, an interface device, an input device, and a display device. The memory device is, for example, SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). Examples of the auxiliary storage device include a HDD (Hard Disc Drive), an SSD (Solid State Disc), an EEPROM (Electrically Erasable Programmable Read-Only Memory), and a flash memory. The interface device includes an external interface for connecting to an external recording medium and a communication interface for communicating with the outside, such as the shovel 100. The input device includes, for example, a lever-type operation input device. The display device is, for example, a liquid crystal display or an organic EL (Electroluminescence) display. The operator uses the input device to perform an operation input regarding the actuator of the shovel 100, and the remote operation support device uses the communication interface to transmit a signal corresponding to the operation input to the shovel 100. This allows the operator to remotely control the excavator 100 using the remote control support device.

Specifically, the excavator 100 transmits an image (hereinafter referred to as "surroundings") representing the surroundings including the front of the excavator 100 based on a captured image output by an imaging device 40 (described later) through a communication device mounted on the excavator 100. image") may be sent to the remote operation support device. The remote operation support device may then display the image (surrounding image) received from the excavator 100 on the display device. Further, various information images (information screens) displayed on the output device 50 (display device 50A) inside the cabin 10 of the excavator 100 may be similarly displayed on the display device of the remote operation support device. As a result, an operator using the remote operation support device can, for example, remotely operate the shovel 100 while checking the display contents such as an image showing the surroundings of the shovel 100 or an information screen displayed on the display device. can. Then, the excavator 100 operates the actuator in response to a remote control signal indicating the content of the remote control, which is received from the remote control support device through the communication device, and the lower traveling structure 1, the upper rotating structure 3, the boom 4, and the arm 5, and driven elements such as bucket 6.

Further, the remote control may include, for example, a mode in which the shovel 100 is operated by external voice input or gesture input to the shovel 100 by a person (for example, a worker) around the shovel 100. Specifically, the excavator 100 receives sounds uttered by surrounding workers, etc. through an audio input device (for example, a microphone), a gesture input device (for example, an imaging device), etc. mounted on the excavator 100. Recognizes gestures etc. performed by Then, the excavator 100 operates the actuator according to the content of the recognized voice, gesture, etc., and moves the undercarriage 1 (left and right crawlers), the upper revolving structure 3, the boom 4, the arm 5, the bucket 6, etc. The drive element may also be driven.

Furthermore, the excavator 100 may automatically operate the actuator regardless of the details of the operator's operation. As a result, the excavator 100 has a function to automatically operate at least some of the driven elements such as the lower traveling body 1, the upper revolving body 3, the boom 4, the arm 5, and the bucket 6 (“automatic operation function” or “MC (Machine Control) function).

The automatic operation function includes, for example, a function that automatically operates a driven element (actuator) other than the driven element (actuator) to be operated in response to an operator's operation on the operating device 26 or remote control (a "semi-automatic operation function"). ” or “operation support type MC function”). Furthermore, the automatic operation function includes a function that automatically operates at least a part of a plurality of driven elements (actuators) on the premise that there is no operator operation on the operating device 26 or remote control (a "fully automatic operation function" or a "full automatic operation function"). Fully automatic MC function) may be included. In the excavator 100, when the fully automatic driving function is enabled, the interior of the cabin 10 may be unmanned. Further, the semi-automatic driving function, fully automatic driving function, etc. may include a mode in which the operation details of a driven element (actuator) that is a target of automatic driving are automatically determined according to predefined rules. In addition, for semi-automatic driving functions and fully automatic driving functions, the excavator 100 autonomously makes various judgments, and based on the judgment results, autonomously determines the operation of the driven element (actuator) that is the target of automatic driving. ("autonomous driving function") may be included.

Further, the work of the shovel 100 may be remotely monitored. In this case, a remote monitoring support device having the same functions as the remote operation support device may be provided. As a result, the supervisor who is the user can use the remote monitoring support device to monitor the work status of the excavator 100 using the automatic operation function while checking the surrounding image displayed on the display device of the remote monitoring support device. I can do it. For example, if the supervisor determines that it is necessary from a safety perspective, the supervisor can perform the operator's operation of the excavator 100 or the automatic operation function of the excavator 100 by inputting a predetermined input using the input device of the remote monitoring support device. It is possible to intervene and make an emergency stop.

[Excavator hardware configuration]
Next, the hardware configuration of the excavator 100 will be described with reference to FIGS. 2 to 6 in addition to FIG. 1.

FIG. 2 is a block diagram showing an example of the hardware configuration of shovel 100. FIG. 3 is a diagram showing an example of a hydraulic circuit of a hydraulic drive system and an operation system of the excavator 100. FIG. 4 is an enlarged view schematically showing an example of the control valve 175R that drives the boom cylinder 7. As shown in FIG. FIG. 5 is an enlarged view schematically showing an example of a control valve 175L that drives the boom cylinder 7. As shown in FIG. FIG. 6 is a diagram showing an example of the hydraulic oil holding circuit 90.

In Figures 2 and 3, the route through which mechanical power is transmitted is a double line, the route through which high-pressure hydraulic fluid that drives the hydraulic actuator flows is a solid line, the route through which pilot pressure is transmitted is a broken line, and the route through which electrical signals are transmitted is a broken line. The transmitted paths are each indicated by a dotted line.

The excavator 100 includes respective components such as a hydraulic drive system for hydraulically driving driven elements, an operation system for operating driven elements, a user interface system for exchanging information with a user, and a control system for various controls.

≪Hydraulic drive system≫
As shown in FIGS. 2 and 3, the hydraulic drive system of the excavator 100 hydraulically drives each of the driven elements such as the lower traveling body 1 (left and right crawlers), the upper rotating body 3, and the attachment AT. It includes a hydraulic actuator HA. Further, the hydraulic drive system of the excavator 100 according to the present embodiment includes an engine 11, a regulator 13, a main pump 14, a control valve 17, negative control throttles 18L and 18R, and a hydraulic oil holding circuit 90.

The hydraulic actuator HA includes travel hydraulic motors 1ML and 1MR, a swing hydraulic motor 2M, a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, and the like.

Note that in the excavator 100, part or all of the hydraulic actuator HA may be replaced with an electric actuator. In other words, the excavator 100 may be a hybrid excavator or an electric excavator.

The engine 11 is the prime mover of the excavator 100 and is the main power source in the hydraulic drive system. The engine 11 is, for example, a diesel engine that uses light oil as fuel. The engine 11 is mounted, for example, at the rear of the upper revolving structure 3. The engine 11 rotates at a predetermined target rotation speed under direct or indirect control by a controller 30, which will be described later, and drives the main pump 14 and the pilot pump 15.

Note that in place of or in addition to the engine 11, another prime mover (for example, an electric motor) or the like may be mounted on the excavator 100.

The regulator 13 controls (adjusts) the discharge amount of the main pump 14 under the control of the controller 30 . For example, the regulator 13 adjusts the angle of the swash plate (hereinafter referred to as "tilt angle") of the main pump 14 in accordance with a control command from the controller 30.

As shown in FIG. 3, the regulator 13 includes regulators 13L and 13R corresponding to main pumps 14L and 14R, respectively, which will be described later.

The main pump 14 supplies hydraulic oil to the control valve 17 through a high pressure hydraulic line. The main pump 14 is, for example, mounted at the rear of the upper revolving structure 3, like the engine 11. The main pump 14 is driven by the engine 11 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and as described above, the stroke length of the piston is adjusted by adjusting the tilt angle of the swash plate by the regulator 13 under the control of the controller 30, and the stroke length of the piston is adjusted. The flow rate and discharge pressure are controlled.

As shown in FIG. 3, the main pump 14 includes main pumps 14L and 14R.

The control valve 17 drives the hydraulic actuator HA in accordance with the contents of an operator's operation on the operating device 26 or remote control, or an operation command regarding an automatic operation function output from the controller 30. The operation command corresponding to the automatic driving function may be generated by the controller 30, or may be generated by another control device (computing device) that performs control regarding the automatic driving function. The control valve 17 is mounted, for example, in the center of the upper revolving body 3. As described above, the control valve 17 is connected to the main pump 14 via a high-pressure hydraulic line, and controls the hydraulic fluid supplied from the main pump 14 according to an operator's operation or an operation command corresponding to an automatic operation function. , selectively supplying each hydraulic actuator.

As shown in FIG. 3, the control valve 17 includes control valves 171, 172, 173, 174, 175L, 175R, and 176L that control the flow rate and flow direction of hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators HA. , 176R.

The hydraulic drive system of excavator 100 circulates hydraulic oil from each of main pumps 14L and 14R driven by engine 11 to hydraulic oil tank T via center bypass oil passages C1L and C1R, and parallel oil passages C2L and C2R.

The center bypass oil passage C1L starts from the main pump 14L, passes through control valves 171, 173, 175L, and 176L arranged in the control valve 17 in order, and reaches the hydraulic oil tank T.

The center bypass oil passage C1R starts from the main pump 14R, passes through control valves 172, 174, 175R, and 176R arranged in the control valve 17 in order, and reaches the hydraulic oil tank T.

The control valve 171 is a spool valve that drives the travel hydraulic motor 1ML. Specifically, the control valve 171 supplies the hydraulic oil discharged by the main pump 14L to one port of the travel hydraulic motor 1ML, and supplies the hydraulic oil in the travel hydraulic motor 1ML from the other port to the hydraulic oil tank T. to be discharged.

The control valve 172 is a spool valve that drives the travel hydraulic motor 1MR. Specifically, the control valve 172 supplies the hydraulic oil discharged by the main pump 14R to one port of the travel hydraulic motor 1MR, and supplies the hydraulic oil in the travel hydraulic motor 1MR from the other port to the hydraulic oil tank T. discharge to.

The control valve 173 is a spool valve that drives the swing hydraulic motor 2M. Specifically, the control valve 173 supplies the hydraulic oil discharged by the main pump 14L to one port of the hydraulic swing motor 2M, and supplies the hydraulic oil in the hydraulic swing motor 2M from the other port to the hydraulic oil tank T. discharge to.

The control valve 174 is a spool valve that drives the bucket cylinder 9. Specifically, the control valve 174 supplies the hydraulic oil discharged by the main pump 14R to one oil chamber of the bucket cylinder 9, and supplies the hydraulic oil in the other oil chamber of the bucket cylinder 9 to the hydraulic oil tank T. Discharge.

The control valves 175L and 175R are spool valves that drive the boom cylinder 7.

The control valve 175R supplies the hydraulic oil discharged by the main pump 14R to one oil chamber of the boom cylinder 7, and discharges the hydraulic oil in the other oil chamber of the boom cylinder 7 to the hydraulic oil tank T. As shown in FIG. 4, the control valve 175R includes a regeneration circuit 175Ra.

The regeneration circuit 175Ra regenerates a portion of the hydraulic oil discharged from the oil chamber on the bottom side of the boom cylinder 7 to the oil chamber on the rod side of the boom cylinder 7 via the check valve 175Rb. Thereby, during the lowering operation of the boom 4, the energy consumption (fuel consumption) of the excavator 100 can be suppressed, and the energy efficiency (fuel consumption rate) of the excavator 100 can be improved.

The control valve 175L supplies the hydraulic oil discharged by the main pump 14R to the oil chamber on the bottom side of the boom cylinder 7, and discharges the hydraulic oil in the oil chamber on the rod side of the boom cylinder 7 to the hydraulic oil tank T. In addition, the control valve 175L discharges the hydraulic oil in the bottom side oil chamber of the boom cylinder 7 to the center bypass oil passage C1L on the downstream side as seen from the control valve 175L. The hydraulic oil is regenerated into the arm cylinder 8 via the control valve 176L. As a result, for example, when the lowering operation of the boom 4 and the opening operation of the arm 5 are performed at the same time, the energy consumption (fuel consumption) of the excavator 100 is suppressed and the energy efficiency (fuel consumption rate) of the excavator 100 is improved. be able to. As shown in FIG. 5, the control valve 175L includes a regeneration circuit 175La.

The regeneration circuit 175La connects an oil passage connected to the oil chamber on the bottom side of the boom cylinder 7 and the downstream side of the center bypass oil passage C1L as viewed from the control valve 175L. The regeneration circuit 175La includes a regeneration throttle 175Lb and a check valve 175Lc.

The regeneration throttle 175Lb is provided closer to the boom cylinder 7 than the check valve 175Lc in the regeneration circuit 175La, and increases the pressure in the regeneration circuit 175La.

The check valve 175Lc is provided closer to the center bypass oil passage C1L than the regeneration throttle 175Lb in the regeneration circuit 175La, and opens as the pressure in the regeneration circuit 175La increases due to the action of the regeneration throttle 175Lb. Thereby, the regeneration circuit 175La can regenerate the hydraulic oil in the bottom side oil chamber of the boom cylinder 7 to the arm cylinder 8 via the center bypass oil passage C1L and the control valve 176L.

Control valves 176L and 176R are spool valves that drive arm cylinder 8. Specifically, the control valve 176L supplies the hydraulic oil discharged by the main pump 14L to one oil chamber of the arm cylinder 8, and supplies the hydraulic oil in the other oil chamber of the arm cylinder 8 to the hydraulic oil tank T. Discharge. The control valve 176R supplies the hydraulic oil discharged by the main pump 14R to one oil chamber of the arm cylinder 8, and discharges the hydraulic oil in the other oil chamber of the arm cylinder 8 to the hydraulic oil tank T.

The control valves 171, 172, 173, 174, 175L, 175R, 176L, and 176R respectively adjust the flow rate of hydraulic oil supplied to and discharged from the hydraulic actuator HA, and control the flow of hydraulic oil depending on the pilot pressure acting on the pilot port. change direction.

The parallel oil passage C2L supplies hydraulic oil of the main pump 14L to the control valves 173, 175L, and 176L in parallel with the center bypass oil passage C1L. Specifically, the parallel oil passage C2L branches from the center bypass oil passage C1L on the upstream side of the control valve 171, and supplies hydraulic oil for the main pump 14L in parallel to each of the control valves 171, 173, 175L, and 176R. configured as possible. As a result, when the flow of hydraulic oil through the center bypass oil passage C1L is restricted or blocked by any of the control valves 171, 173, and 175L, the parallel oil passage C2L supplies hydraulic oil to the downstream control valve. can.

The parallel oil passage C2R supplies hydraulic oil of the main pump 14R to the control valves 174, 175R, and 176R in parallel with the center bypass oil passage C1R. Specifically, the parallel oil passage C2R branches from the center bypass oil passage C1R on the upstream side of the control valve 172, and supplies hydraulic oil for the main pump 14R in parallel to each of the control valves 172, 174, 175R, and 176R. configured as possible. Thereby, when the flow of hydraulic oil passing through the center bypass oil passage C1R is restricted or blocked by any of the control valves 172, 174, and 175R, the parallel oil passage C2R supplies hydraulic oil to the downstream control valve. can.

The hydraulic oil holding circuit 90 maintains the hydraulic oil (hydraulic pressure) in the oil chamber on the bottom side of the boom cylinder 7 when the boom 4 is not operated in the lowering direction (hereinafter referred to as "boom lowering operation") through the operating device 26. ) to hold. As a result, for example, the hydraulic oil holding circuit 90 can prevent the boom 4 from falling in the downward direction even if hydraulic oil leaks or the like occurs on the downstream side when the boom cylinder 7 side is the upstream side. The situation can be prevented.

As shown in FIG. 6, the hydraulic oil holding circuit 90 is provided in a high-pressure hydraulic line that connects the control valve 17 and the oil chamber on the bottom side of the boom cylinder 7. The hydraulic oil holding circuit 90 mainly includes a holding valve 90a and a spool valve 90b. In this example, two boom cylinders 7 are shown in FIG. The same applies to Therefore, the hydraulic circuit for one boom cylinder 7 (the right boom cylinder 7 in the figure) will be mainly explained.

The holding valve 90a allows hydraulic oil to flow from the control valve 17 into the oil chamber on the bottom side of the boom cylinder 7. Specifically, the holding valve 90a responds to an operation in the raising direction of the boom 4 with respect to the operating device 26 (hereinafter referred to as "boom raising operation"), and controls the hydraulic oil supplied from the control valve 17 through the oil passage 901. The oil is supplied to the bottom side oil chamber of the boom cylinder 7 through a passage 903. On the other hand, the holding valve 90a blocks outflow of hydraulic oil from the oil chamber (oil passage 903) on the bottom side of the boom cylinder 7 to the oil passage 901 connected to the control valve 17. The holding valve 90a is, for example, a poppet valve.

The holding valve 90a is connected to one end of an oil passage 902 branching from the oil passage 901, and the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7 is transferred to the downstream oil passage through a spool valve 90b arranged in the oil passage 902. 901 (control valve 17). Specifically, when the spool valve 90b provided in the oil passage 902 is in a non-communicating state (the spool position at the left end in the figure), the holding valve 90a maintains the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7. It is held so that it is not discharged to the downstream side (oil path 901) of the holding circuit 90. On the other hand, when the spool valve 90b is in a communicating state (the spool position at the center or right end in the figure), the holding valve 90a transfers the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7 via the oil passage 902. It can be discharged downstream of the holding circuit 90.

The spool valve 90b is provided in the oil passage 902 and allows the hydraulic oil in the side oil chamber at the bottom of the boom cylinder 7, which is shut off by the holding valve 90a, to bypass and discharge downstream of the hydraulic oil holding circuit 90 (oil passage 901). be able to. The spool valve 90b has a first spool position where the oil passage 902 is disconnected (the leftmost spool position in the figure), and a second spool position where the oil passage 902 is throttled and communicated (the center spool position in the figure). ), and a third spool position (the spool position at the right end in the figure) where the oil passage 902 is fully opened and communicated. At this time, in the second spool position, the degree of throttling of the spool valve 90b is varied depending on the magnitude of the pilot pressure input to the pilot port.

When no pilot pressure is input to the pilot port of the spool valve 90b, the spool is in the first spool position, and the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7 is transferred to the hydraulic oil holding circuit 90 via the oil passage 902. is not discharged downstream (oil path 901). On the other hand, when pilot pressure is input to the pilot port of the spool valve 90b, the spool is in either the second position or the third position depending on the magnitude of the pilot pressure. Specifically, in the spool valve 90b, as the pilot pressure acting on the pilot port increases, the degree of throttling at the second position decreases, and the spool approaches the third spool position from the second spool position. The spool valve 90b moves the spool to the third spool position when the pilot pressure acting on the pilot port increases to a certain extent.

Further, in this example, a pilot circuit for inputting pilot pressure to the spool valve 90b is provided. This pilot circuit includes a pilot pump 15, a boom lowering remote control valve 26Aa, an electromagnetic proportional valve 92, and a shuttle valve 94.

The boom lowering remote control valve 26Aa is connected to the pilot pump 15 through a pilot line 25A. The boom lowering remote control valve 26Aa is included in a lever device that operates the boom cylinder 7 of the operating device 26, and uses hydraulic oil supplied from the pilot pump 15 to pilot the pilot pressure corresponding to the boom lowering operation. Output to line 27A.

The electromagnetic proportional valve 92 branches from the pilot line 25A between the pilot pump 15 and the boom lowering remote control valve 26Aa, and connects to one input port of the shuttle valve 94 by bypassing the boom lowering remote control valve 26Aa. It is provided in line 25B. The electromagnetic proportional valve 92 can switch communication/non-communication of the pilot line 25B in response to a control command from the controller 30, and can proportionally change the flow path area, that is, the flow rate when the pilot line 25B is in the communication state. can.

Note that instead of the electromagnetic proportional valve 92, an electromagnetic switching valve that can only switch between a communicating state and a non-communicating state of the pilot line 25B may be employed.

In the shuttle valve 94, one end of the pilot line 25B is connected to one input port, and one end of the pilot line 27A on the secondary side of the boom lowering remote control valve 26Aa is connected to the other port. The shuttle valve 94 outputs the hydraulic fluid whose pilot pressure is higher among the two input ports to the pilot port of the spool valve 90b. As a result, when the boom is being lowered, pilot pressure is applied from the shuttle valve 94 to the pilot port of the spool valve 90b, and the spool valve 90b is brought into communication. Therefore, in response to the boom lowering operation on the operating device 26 (lever device), the spool valve 90b supplies the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7 via the oil path 902 downstream of the hydraulic oil holding circuit 90 (oil 901). In other words, the spool valve 90b is linked to the boom lowering operation on the operating device 26, and when the boom lowering operation is performed through the operating device 26, the spool valve 90b transfers the hydraulic oil shut off by the holding valve 90a to the oil chamber on the bottom side of the boom cylinder 7. discharge from. Further, even when the boom is not lowered through the operating device 26, the shuttle valve 94 is connected to the pilot port of the spool valve 90b from the electromagnetic proportional valve 92 via the shuttle valve 94 under the control of the controller 30. Pilot pressure can be applied. Therefore, the controller 30 cancels the hydraulic oil holding function of the hydraulic oil holding circuit 90 (spool valve 90b) via the electromagnetic proportional valve 92, and the oil By bringing the passage 902 into communication, the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7 can be discharged downstream of the hydraulic oil holding circuit 90 (oil passage 901).

≪Operation system≫
As shown in FIGS. 2 and 3, the operating system of the excavator 100 includes a pilot pump 15, an operating device 26, and a hydraulic control valve 60.

The pilot pump 15 supplies pilot pressure to various hydraulic devices via a pilot line 25. The pilot pump 15 is, for example, mounted at the rear of the upper revolving structure 3, like the engine 11. The pilot pump 15 is, for example, a fixed capacity hydraulic pump, and is driven by the engine 11 as described above.

Note that the pilot pump 15 may be omitted. In this case, the relatively high pressure hydraulic oil discharged from the main pump 14 may be reduced in pressure by a predetermined pressure reducing valve, and then the relatively low pressure hydraulic oil may be supplied as pilot pressure to various hydraulic devices.

The operating device 26 is provided near the cockpit of the cabin 10 and is used by an operator to operate various driven elements. Specifically, the operating device 26 is used for an operator to operate the hydraulic actuator HA that drives each driven element, and as a result, the operator operates the driven element to be driven by the hydraulic actuator HA. can be realized. The operating device 26 includes a pedal device and a lever device for operating each driven element (hydraulic actuator HA).

For example, as shown in FIG. 2, the operating device 26 is of a hydraulic pilot type. Specifically, the operating device 26 uses hydraulic oil supplied from the pilot pump 15 through the pilot line 25 and outputs pilot pressure according to the operation content to the pilot line 27 on the secondary side. Pilot line 27 is connected to control valve 17 . Thereby, a pilot pressure can be input to the control valve 17 according to the operation contents regarding various driven elements (hydraulic actuator HA) in the operating device 26. Therefore, the control valve 17 can drive each hydraulic actuator HA according to the operation performed on the operating device 26 by an operator or the like.

Moreover, the operating device 26 may be electrical. Specifically, the operating device 26 outputs an electrical signal (hereinafter referred to as an "operating signal") according to the content of the operation, and the operating signal is taken into the controller 30. Then, in response to the operation signal, the controller 30 sends a control command corresponding to the operation details of the operation device 26 to a hydraulic control valve (hereinafter referred to as , "control valve for operation"). As a result, pilot pressure corresponding to the operation details of the operating device 26 is inputted from the operation control valve to the control valve 17, and the control valve 17 drives each hydraulic actuator HA according to the operation details of the operating device 26. be able to. As a result, pilot pressure corresponding to the operation content of the operating device 26 is supplied from the operating control valve to the control valve 17. Therefore, the control valve 17 can realize the operation of each hydraulic actuator HA according to the operation content of the operating device 26 by an operator or the like.

Further, when the excavator 100 is remotely operated or remotely monitored, an operation control valve may be used. For example, the controller 30 outputs a control command according to the content of the remote operation to the operation control valve in response to a remote operation signal received from a remote operation support device or a remote monitoring support device. As a result, pilot pressure corresponding to the content of the remote control is supplied from the operation control valve to the control valve 17. Therefore, the control valve 17 can realize the operation of each hydraulic actuator HA according to the details of the remote operation by the remote operator.

Similarly, when the excavator 100 has an automatic operation function, an operation control valve may be used. For example, the controller 30 outputs a control command corresponding to the operation command to the operation control valve in response to an operation command representing the operation of the hydraulic actuator HA by the automatic operation function. The operation command may be generated by the controller 30 or by another control device. Thereby, pilot pressure corresponding to the operation of the hydraulic actuator by the automatic operation function is supplied from the operation control valve to the control valve 17. Therefore, the control valve 17 can realize the operation of each hydraulic actuator HA corresponding to the automatic operation function.

Furthermore, the control valves built into the control valve 17 and driving the respective hydraulic actuators HA may be of an electromagnetic solenoid type. In this case, an operation signal output from the operation device 26, a remote operation signal, or an operation command indicating the operation of the hydraulic actuator HA by the automatic operation function is directly input to the control valve 17, that is, to the electromagnetic solenoid type control valve. It's okay. Thereby, the electromagnetic solenoid type control valve of the control valve 17 can realize the operation of each hydraulic actuator HA in accordance with the operation contents of the operator or the operation command corresponding to the automatic operation function.

Further, as described above, part or all of the hydraulic actuator HA may be replaced with an electric actuator. In this case, the controller 30 may output a control command according to an operation signal of the operation device 26, a remote control signal, or an operation command corresponding to the automatic driving function to the electric actuator or a driver driving the electric actuator. Thereby, the electric actuator can realize the operation of each hydraulic actuator HA in accordance with the operation contents of the operator or the operation command corresponding to the automatic driving function.

The operating device 26 includes, for example, a lever device that operates each of the boom 4 (boom cylinder 7), the arm 5 (arm cylinder 8), the bucket 6 (bucket cylinder 9), and the upper swing structure 3 (swing hydraulic motor 2M). include. Further, the operating device 26 includes, for example, a pedal device or a lever device that operates each of the left and right lower traveling bodies 1 (travel hydraulic motors 1ML, 1MR).

The hydraulic control valve 60 is operated by a control command (control current) from the controller 30, and uses hydraulic oil supplied from the pilot pump 15 through the pilot line 25 to control the pilot control valve 175L corresponding to the lowering operation of the boom 4. Supply pilot pressure to the port. The controller 30 outputs a control command to the hydraulic control valve 60 when the lowering operation of the boom 4 and the opening operation of the arm 5 are performed simultaneously. For example, the controller 30 determines whether the lowering operation of the boom 4 and the opening operation of the arm 5 are being performed at the same time, depending on the operation contents of the operating device 26, the contents of the remote control signal, or the contents of the operation command. I can judge. Further, the controller 30 may determine whether or not the lowering operation of the boom 4 and the opening operation of the arm 5 are being performed at the same time, for example, based on the captured image of the imaging device 40 (camera 40F). As a result, the hydraulic control valve 60 moves the spool of the control valve 175L to the right in FIG. It can be supplied to the oil chamber on the rod side of the arm cylinder 8. The controller 30 adjusts the amount of movement of the spool of the control valve 175L from the neutral position through the hydraulic control valve 60, and adjusts the amount of movement of the spool of the control valve 175L from the bottom side oil chamber of the boom cylinder 7 to the rod side oil chamber of the arm cylinder 8 through the regeneration circuit 175La. The regeneration flow rate of hydraulic oil can be adjusted.

≪User interface system≫
As shown in FIGS. 1 to 3, the user interface system of excavator 100 includes an operating device 26, an output device 50, and an input device 52.

The output device 50 outputs various information to the user of the excavator 100 (for example, the operator in the cabin 10 or an external remote control operator) and the people around the excavator 100 (for example, a worker or a driver of a work vehicle). Output. The output device 50 includes a display device 50A and a sound output device 50B.

The display device 50A displays various information images and outputs various information to the user in a visual manner. The display device 50A is, for example, a liquid crystal display or an organic EL display.

Further, the output device 50 may include, for example, a lighting device such as a warning light that outputs various information in a visual manner.

For example, as shown in FIG. 1, a display device 50A and a lighting device may be provided inside the cabin 10 and output various information visually to an operator inside the cabin 10. In addition, the display device 50A and lighting equipment are provided outside the cabin 10, such as on the side of the upper revolving body 3, instead of inside the cabin 10, or in addition, so that they are visually visible to workers and the like around the excavator 100. Various information may be output using various methods.

The sound output device 50B outputs various information using an auditory method. The sound output device 50B includes, for example, a buzzer, a speaker, and the like. The sound output device 50B is provided, for example, in at least one of the interior and exterior of the cabin 10, and outputs various information in an auditory manner to the operator inside the cabin 10 and the people (workers, etc.) around the excavator 100. It's fine.

Further, the output device 50 may include a device that outputs various information to the user using a tactile method such as vibration of a cockpit inside the cabin 10.

The input device 52 receives various inputs from the user of the excavator 100. Signals corresponding to inputs accepted by input device 52 are captured by controller 30 . The input device 52 is provided inside the cabin 10 , for example, and receives input from an operator inside the cabin 10 . Further, the input device 52 may be provided outside the cabin 10, such as on the side surface of the upper revolving structure 3, for example, and may receive input from a worker or the like around the excavator 100.

For example, the input device 52 includes an operation input device that receives mechanical input from the user. The operation input device may include a touch panel mounted on the display device, a touch pad installed around the display device, a button switch, a lever, a toggle, a knob switch provided on the operation device 26 (lever device), etc. .

Furthermore, the input device 52 may include a voice input device that accepts voice input from a user. The audio input device includes, for example, a microphone.

Input device 52 may also include a gesture input device that accepts gesture input from the user. The gesture input device includes, for example, an imaging device that captures an image of a gesture performed by a user.

Furthermore, the input device 52 may include a biometric input device that receives biometric input from the user. The biometric input includes, for example, input of biometric information such as a user's fingerprint or iris.

≪Control system≫
As shown in FIGS. 2 and 3, the control system of the excavator 100 according to this embodiment includes a controller 30. The control system of the excavator 100 also includes an operating pressure sensor 29, an imaging device 40, a boom attitude sensor S1, an arm attitude sensor S2, a body tilt sensor S4, a swing state sensor S5, and a boom cylinder pressure sensor S7. , and an arm cylinder pressure sensor S8.

The controller 30 performs various controls regarding the shovel 100.

The functions of the controller 30 may be realized by arbitrary hardware or a combination of arbitrary hardware and software. For example, as shown in FIG. 2, the controller 30 includes an auxiliary storage device 30A, a memory device 30B, a CPU 30C, and an interface device 30D, which are connected by a bus B1.

The auxiliary storage device 30A is a non-volatile storage means, and stores installed programs as well as necessary files, data, and the like. The auxiliary storage device 30A is, for example, an EEPROM or a flash memory.

For example, when there is an instruction to start a program, the memory device 30B loads the program in the auxiliary storage device 30A so that the CPU 30C can read the program. The memory device 30B is, for example, an SRAM.

For example, the CPU 30C executes a program loaded into the memory device 30B, and implements various functions of the controller 30 according to instructions of the program.

The interface device 30D functions as a communication interface for connecting to a communication line inside the excavator 100, for example. The interface device 30D may include a plurality of different types of communication interfaces depending on the type of communication line to be connected.

Further, the interface device 30D functions as an external interface for reading data from and writing data to the recording medium. The recording medium is, for example, a dedicated tool that is connected to a connector installed inside the cabin 10 with a detachable cable. Further, the recording medium may be a general-purpose recording medium such as an SD memory card or a USB (Universal Serial Bus) memory. Thereby, programs for realizing various functions of the controller 30 can be provided by, for example, a portable recording medium and installed in the auxiliary storage device 30A of the controller 30. Further, the program may be downloaded from another computer outside the excavator 100 through a communication device installed in the excavator 100 and installed in the auxiliary storage device 30A.

Note that some of the functions of the controller 30 may be realized by another controller (control device). That is, the functions of the controller 30 may be realized in a distributed manner by a plurality of controllers.

The operating pressure sensor 29 detects the pilot pressure on the secondary side (pilot line 27A) of the hydraulic pilot type operating device 26, that is, the pilot pressure corresponding to the operating state of each driven element (hydraulic actuator) in the operating device 26. To detect. A detection signal of pilot pressure corresponding to the operating state of each driven element (hydraulic actuator HA) in the operating device 26 by the operating pressure sensor 29 is taken into the controller 30.

Note that if the operating device 26 is an electric type, the operating pressure sensor 29 is omitted. This is because the controller 30 can grasp the operating state of each driven element through the operating device 26 based on the operating signal taken in from the operating device 26.

The imaging device 40 acquires images around the excavator 100. The imaging device 40 may also acquire (generate) three-dimensional data representing the position and external shape of objects around the excavator 100 within the imaging range (angle of view) based on the acquired image and distance-related data described below. good. The three-dimensional data of objects around the shovel 100 is, for example, coordinate information data of a point group representing the surface of the object, distance image data, and the like.

For example, as shown in FIG. 1, the imaging device 40 includes a camera 40F that images the front of the upper revolving structure 3, a camera 40B that images the rear of the upper revolving structure 3, and a camera 40L that images the left side of the upper revolving structure 3. , and a camera 40R that images the right side of the upper rotating body 3. Thereby, the imaging device 40 can image the entire circumference of the excavator 100, that is, the range covering the angular direction of 360 degrees, when the excavator 100 is viewed from above. In addition, the operator visually recognizes peripheral images such as captured images of the cameras 40B, 40L, and 40R and processed images generated based on the captured images through the display device 50A and the remote operation support device (display device), and You can check the left, right, and rear of 3. In addition, the operator can control the operation of the attachment AT including the bucket 6 by visually checking peripheral images such as images captured by the camera 40F and processed images generated based on the captured images through the remote operation support device (display device). The shovel 100 can be remotely controlled while checking the information. Further, the supervisor can monitor the working status of the excavator 100 by visually recognizing peripheral images such as images captured by the cameras 40F, 40B, 40L, and 40R and processed images generated based on the captured images. Hereinafter, the cameras 40F, 40B, 40L, and 40R may be collectively or individually referred to as "camera 40X."

Camera 40X is, for example, a monocular camera. In addition, the camera 40X acquires data regarding distance (depth) in addition to two-dimensional images, such as a stereo camera, a TOF (Time Of Flight) camera, etc. (hereinafter collectively referred to as a "3D camera"). It may be possible.

Output data (for example, image data, three-dimensional data of objects around the excavator 100, etc.) from the imaging device 40 (camera 40X) is taken into the controller 30 through a one-to-one communication line or an in-vehicle network. Thereby, for example, the controller 30 can monitor objects around the excavator 100 based on the output data of the camera 40X. Further, for example, the controller 30 can determine the surrounding environment of the excavator 100 based on the output data of the camera 40X. Further, for example, the controller 30 can determine the posture state of the attachment AT shown in the captured image based on the output data of the camera 40X (camera 40F). Further, for example, the controller 30 can determine the attitude state of the body of the excavator 100 (the upper revolving body 3) based on the output data of the camera 40X, with reference to objects around the excavator 100.

Note that some or all of the cameras 40F, 40B, 40L, and 40R may be omitted. For example, when the excavator 100 is not remotely controlled, the camera 40F and the camera 40L may be omitted. This is because it is relatively easy for the operator in the cabin 10 to check the front and left side of the excavator 100. Further, instead of or in addition to the imaging device 40 (camera 40X), a distance sensor may be provided in the upper revolving body 3. The distance sensor is attached to the upper part of the upper revolving body 3, for example, and acquires data regarding the distance and direction of surrounding objects with respect to the shovel 100 as a reference. Further, the distance sensor may acquire (generate) three-dimensional data (for example, coordinate information data of a point group) of objects around the shovel 100 within the sensing range based on the acquired data. The distance sensor is, for example, LIDAR (Light Detection and Ranging). Further, for example, the distance sensor may be, for example, a millimeter wave radar, an ultrasonic sensor, an infrared sensor, or the like.

The boom attitude sensor S1 is attached to the boom 4 and detects an attitude angle (hereinafter referred to as "boom angle") around the rotation axis of the base end corresponding to the connection part of the boom 4 with the upper revolving structure 3. The boom attitude sensor S1 includes, for example, a rotary potentiometer, a rotary encoder, an acceleration sensor, an angular acceleration sensor, a 6-axis sensor, an IMU (Inertial Measurement Unit), and the like. Hereinafter, the same may be applied to the arm attitude sensor S2 and the body tilt sensor S4. Further, the boom attitude sensor S1 may include a cylinder sensor that detects the extended/contracted position of the boom cylinder 7. Hereinafter, the same may be applied to the arm posture sensor S2. A detection signal of the boom angle by the boom attitude sensor S1 is taken into the controller 30. Thereby, the controller 30 can grasp the attitude state of the boom 4.

The arm posture sensor S2 is attached to the arm 5 and detects the posture angle (hereinafter referred to as "arm angle") around the rotation axis of the base end of the arm 5, which corresponds to the connecting portion with the boom 4. The arm angle detection signal from the arm posture sensor S2 is taken into the controller 30. Thereby, the controller 30 can grasp the posture state of the arm 5.

The body inclination sensor S4 detects the inclination state of the body (for example, the upper revolving body 3) with respect to a predetermined reference plane (for example, a horizontal plane). The body inclination sensor S4 is, for example, attached to the revolving upper structure 3, and is configured to measure the inclination angle (hereinafter referred to as "front-rear inclination angle" and "left-right Detect the angle of inclination). A detection signal corresponding to the inclination angle (the longitudinal inclination angle and the lateral inclination angle) detected by the aircraft inclination sensor S4 is taken into the controller 30. Thereby, the controller 30 can grasp the tilting state of the aircraft body (upper rotating body 3).

The turning state sensor S5 is attached to the revolving upper structure 3 and outputs detection information regarding the turning state of the revolving upper structure 3. The turning state sensor S5 detects, for example, the turning angular velocity and turning angle of the upper rotating structure 3. The turning state sensor S5 includes, for example, a gyro sensor, a resolver, a rotary encoder, and the like. Detection information regarding the turning state detected by the turning state sensor S5 is taken into the controller 30.

In addition, when the body inclination sensor S4 includes a gyro sensor, a 6-axis sensor, an IMU, etc. that can detect angular velocity around three axes, the turning state of the upper rotating body 3 (for example, turning angular velocity) may be detected. In this case, the turning state sensor S5 may be omitted.

The boom cylinder pressure sensor S7 is attached to the boom cylinder 7 and detects the pressure of hydraulic oil in the oil chamber of the boom cylinder 7. Boom cylinder pressure sensor S7 includes a boom rod pressure sensor S7R and a boom bottom pressure sensor S7B.

The boom rod pressure sensor S7R and the boom bottom pressure sensor S7B measure the pressure of hydraulic oil in the oil chamber on the rod side of the boom cylinder 7 (hereinafter referred to as "boom rod pressure") and the pressure of hydraulic oil in the oil chamber on the bottom side (hereinafter referred to as "boom rod pressure"), respectively. Hereinafter, "boom bottom pressure") is detected. Detection signals corresponding to the boom rod pressure and boom bottom pressure from the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B are respectively taken into the controller 30.

Arm cylinder pressure sensor S8 is attached to arm cylinder 8 and detects the pressure of hydraulic oil in the oil chamber of arm cylinder 8. Arm cylinder pressure sensor S8 includes an arm rod pressure sensor S8R and an arm bottom pressure sensor S8B.

The arm rod pressure sensor S8R and the arm bottom pressure sensor S8B measure the pressure in the oil chamber on the rod side of the arm cylinder 8 (hereinafter referred to as "arm rod pressure") and the pressure in the oil chamber on the bottom side (hereinafter referred to as "arm bottom"), respectively. pressure”) is detected. Detection signals corresponding to arm rod pressure and arm bottom pressure from arm rod pressure sensor S8R and arm bottom pressure sensor S8B are respectively taken into controller 30.

[Functional configuration of excavator]
Next, the functional configuration of the excavator 100 (controller 30) will be described with reference to FIGS. 7 to 10 in addition to FIGS. 1 to 6.

FIG. 7 is a functional block diagram showing an example of the functional configuration of the shovel 100 (controller 30). FIG. 8 is a diagram illustrating an example of a state immediately before an operation (hereinafter referred to as an "earth removal operation" for convenience) of discharging materials such as earth and sand from the bucket 6 of the excavator 100 to the outside. Hereinafter, the x-axis and the y-axis are defined along the operating surface of the attachment AT, and the z-axis is defined along the rotation axis of each link (boom 4, arm 5, and bucket 6) of the attachment AT, FIG. The explanation may be given using an orthogonal coordinate system (xyz coordinate system). For example, with respect to the ground (horizontal surface) on which the shovel 100 is located, the x-axis and z-axis are defined in the horizontal direction, and the y-axis is defined in the vertical direction. FIGS. 9 and 10 are diagrams showing one example and other examples of displays regarding the degree of stability of the behavior of the shovel 100. Specifically, FIGS. 9 and 10 are specific examples of displays regarding the degree of stability of the behavior of the shovel 100 when the attachment AT of the shovel 100 is stationary and when it is moving, respectively.

The controller 30 includes a calculation section 301, a determination section 302, a prediction section 303, and a control section 304 as functional sections.

The calculation unit 301 performs various calculations for controlling the behavior of the shovel 100.

For example, the calculation unit 301 calculates the external force acting on the bucket 6 based on the outputs of the boom attitude sensor S1, arm attitude sensor S2, body tilt sensor S4, turning state sensor S5, boom cylinder pressure sensor S7, and arm cylinder pressure sensor S8. Calculate FE. External force FE is a vector. The external force FE includes a force acting due to gravity, a reaction force due to contact with the ground, and a dynamic force (inertial force) generated due to acceleration.

In this example, the excavator 100 is not equipped with a sensor that detects the posture angle of the bucket 6 or a sensor that detects the pressure of hydraulic oil in the oil chamber of the bucket cylinder 9. Therefore, for example, for each of the boom 4, arm 5, and bucket 6, the external force FE and the sparse force application point are FP becomes unknown. In this case, since there are x-axis components and y-axis components of the force application point FP and the external force FE, there are four unknowns. Therefore, the number of unknowns is greater than the number of equations, and the equations cannot be completely solved, making it impossible to obtain the external force FE.

Therefore, in this example, the calculation unit 301 assumes the position of the force application point FP as seen from the arm 5. As a result, the position (x-axis component and y-axis component) of the force application point FP is no longer unknown. Therefore, the calculation unit 301 calculates the external force FE (x-axis component and y-axis component) using equations (two) representing the moments τ1 and τ2 acting on the rotational shafts of the base ends of the boom 4 and the arm 5, respectively. You can ask for it.

For example, the calculation unit 301 calculates the point of force FP using a formula, map, table, etc. prepared in advance, taking into consideration the operation details of the shovel 100, the operation details of the shovel 100, the posture states of the boom 4 and the arm 5, etc. Assume (predict) the position of . For example, when the excavator 100 is performing an excavation operation, it can be assumed that the external force FE is acting on the toe of the bucket 6. Further, when the excavator 100 is performing an excavation operation, the range of the attitude of the bucket 6 can be assumed from the attitude of the boom 4 and the arm 5. Further, for example, when the bucket 6 is not on the ground but in the air, the point of force FP of the bucket 6 can be assumed to be the center of gravity of the bucket 6. Further, when the bucket 6 of the excavator 100 is not on the ground but in the air, the range of the attitude state of the bucket 6 can be assumed from the operation details of the shovel 100 and the attitude states of the boom 4 and arm 5. Therefore, based on these assumptions, the calculation unit 301 can assume the position of the force application point FP using equations, maps, tables, etc.

Further, for example, the calculation unit 301 calculates a moment acting on the shovel 100 around the fulcrum FL of the front end of the ground contact surface of the shovel 100. Specifically, the calculation unit 301 calculates a moment in a direction that causes the shovel 100 to fall forward around the fulcrum FL (hereinafter referred to as "overturning moment") and a moment in a direction that suppresses overturning of the shovel 100 (hereinafter referred to as "stability moment"). ) may be calculated. The overturning moment is a moment that acts on the shovel 100 clockwise around the fulcrum FL in FIG. 8, and the stabilizing moment is a moment that acts on the shovel 100 counterclockwise around the fulcrum FL in FIG.

The position of the fulcrum FL changes depending on the turning state (turning angle) of the upper rotating structure 3 with respect to the lower traveling structure 1. For example, as shown in FIG. 8, when the upper rotating structure 3 is in a rotating state in which the orientation of the upper rotating structure 3 forms an angle of 90 degrees with respect to the direction (progressing direction) of the lower traveling structure 1, the position of the fulcrum FL ( x-axis direction) is closest to the center of rotation of the upper rotating body 3. On the other hand, in the rotating state of the upper rotating body 3 in which the orientation of the upper rotating body 3 is the same as the orientation of the lower traveling body 1 (aligned), the position of the fulcrum FL (x-axis direction) is Farthest from the center. For example, the calculation unit 301 can calculate the position of the fulcrum FL according to the turning state of the upper revolving structure 3 by using a formula, map, table, etc. prepared in advance.

The overturning moment is caused by the external force FE acting on the attachment AT (bucket 6) and the gravity acting on the attachment AT. The calculation unit 301 can calculate the overturning moment based on information regarding the specifications of the attachment AT prepared in advance, the inclination state of the aircraft, the attitude state of the attachment AT, and the external force FE calculated above. For example, the information regarding the specifications of the attachment AT includes information regarding the link lengths of the boom 4, arm 5, and bucket 6, information regarding the center of gravity position, information regarding the mass (weight), etc., and is stored in advance in the auxiliary storage device 30A of the controller 30. be registered. Further, for example, the attitude state of the bucket 6 among the attitude states of the attachment AT is assumed (predicted) in the same manner as in the calculation of the external force FE.

The stability moment is generated due to the mass (weight) of the vehicle body including the lower traveling body 1 and the upper rotating body 3. The calculation unit 301 can calculate the stability moment based on information regarding the specifications of the aircraft prepared in advance. For example, information regarding the specifications of the aircraft includes information regarding the positions of the centers of gravity of the lower traveling body 1 and the upper rotating body 3, information regarding the weights (mass), and the like, and is registered in advance in the auxiliary storage device 30A of the controller 30.

The determination unit 302 determines whether conditions (hereinafter referred to as "regeneration conditions") are established for the hydraulic oil in the bottom side oil chamber of the boom cylinder 7 to be regenerated into the rod side oil chamber of the arm cylinder 8 through the regeneration circuit 175La. Determine whether or not. For example, the determining unit 302 determines whether the regeneration condition is satisfied by determining the operating states of the boom 4 (boom cylinder 7) and arm 5 (arm cylinder 8) based on the output of the operating pressure sensor 29.

The prediction unit 303 predicts whether or not there is a possibility that the excavator 100 will exhibit unstable behavior when the determination unit 302 determines that the regeneration condition is satisfied. The unstable behavior of the shovel 100 includes, for example, the shovel 100 falling forward, the body of the shovel 100 vibrating, and the like. Specifically, the prediction unit 303 may predict whether there is a possibility that the overturning moment of the excavator 100 will exceed the stability moment. This is because if the overturning moment of the shovel 100 exceeds the stability moment, the shovel 100 may fall forward or vibrations in the pitching direction are excited in the shovel 100.

For example, the prediction unit 303 derives a condition for the external force FE (hereinafter referred to as an "unstable condition") when there is a high possibility that the overturning moment will exceed the stability moment when the regeneration condition transitions from a state in which it is not satisfied to a state in which it is satisfied. . As a result, the regeneration of hydraulic oil from the bottom side oil chamber of the boom cylinder 7 to the rod side oil chamber of the arm cylinder 8 through the regeneration circuit 175La is started, that is, at the timing when the external force is relatively small. Unstable conditions can be set. Therefore, the prediction unit 303 can use the unstable condition to predict at an earlier timing that there is a possibility that the excavator 100 will exhibit unstable behavior. Specifically, the prediction unit 303 determines the unstable condition based on the difference between the calculated value of the external force FE when the regeneration condition transitions from the state in which it is not satisfied to the state in which it is satisfied, and the calculated values of the stability moment and the overturning moment. , a threshold value regarding the magnitude of the external force FE may be set. Furthermore, the prediction unit 303 may set a boundary line of the external force FE (vector), which corresponds to an unstable condition, on a two-dimensional (x-axis and y-axis) plane. Then, the prediction unit 303 may predict that there is a high possibility that the overturning moment will exceed the stability moment when the unstable condition is satisfied.

The control unit 304 controls the behavior of the shovel 100.

For example, the control unit 304 performs control related to stabilizing the behavior of the excavator 100.

When the unstable condition is established by the prediction unit 303, the control unit 304 controls the regeneration flow rate of hydraulic oil from the bottom side oil chamber of the boom cylinder 7 to the rod side oil chamber of the arm cylinder 8 through the regeneration circuit 175La. It may be made smaller than the normal reference state. As described above, the control unit 304 can adjust the regeneration flow rate of hydraulic oil from the bottom side oil chamber of the boom cylinder 7 to the rod side oil chamber of the arm cylinder 8 by controlling the hydraulic control valve 60. can. Thereby, the acceleration of the boom 4 and the arm 5 can be kept relatively small when the lowering operation of the boom 4 and the opening operation of the arm 5 are performed simultaneously. Therefore, for example, during the earth unloading operation of the excavator 100 in which the boom 4 is lowered and the arm 5 is opened at the same time, an increase in the external force FE acting on the attachment AT (bucket 6) is suppressed, making the excavator 100 unstable. The occurrence of such behavior can be suppressed.

On the other hand, if the unstable condition is not established by the prediction unit 303, the control unit 304 regenerates the hydraulic oil from the bottom side oil chamber of the boom cylinder 7 to the rod side oil chamber of the arm cylinder 8 through the regeneration circuit 175La. Bring the flow rate to normal reference conditions. As a result, even if the lowering operation of the boom 4 and the opening operation of the arm 5 are performed at the same time, the control unit 304 can improve the working efficiency of the excavator 100 in a situation where there is no possibility of unstable behavior of the excavator 100. can be maintained. Situations in which there is no possibility of unstable behavior of excavator 100 include, for example, a case where the contents of bucket 6 are relatively small, that is, smaller than a predetermined standard. This is because when the contents of the bucket 6 are relatively small, the external force (inertial force) generated on the bucket 6 becomes small when the boom 4 is lowered and the arm 5 is opened simultaneously. In addition, a situation in which there is no possibility of unstable behavior of the excavator 100 occurs, for example, when the difference between the orientation of the upper rotating body 3 and the orientation of the lower traveling body 1 is relatively small, that is, smaller than a predetermined standard. is included. The smaller the difference between the orientation of the upper rotating body 3 and the orientation of the lower traveling body 1, the further the fulcrum FL of forward falling of the excavator 100 is from the center of the excavator 100, and as a result, the stabilizing moment becomes relatively large. This is because the overturning moment becomes relatively small.

Further, for example, the control unit 304 controls the visualization of the degree of stability regarding the behavior of the excavator 100 to the user.

The control unit 304 evaluates the degree of stability of the behavior of the shovel 100 based on the value obtained by subtracting the value of the overturning moment from the value calculated by the calculation unit 301 of the stability moment, and displays the degree of stability of the behavior of the shovel 100 on the display device 50A. May be displayed. This is because it is considered that the larger the subtraction value of the overturning moment from the stability moment of the excavator 100, the higher the stability of the behavior of the excavator 100, and conversely, the smaller the subtraction value, the lower the stability of the behavior of the excavator 100. .

For example, as shown in FIGS. 9 and 10, under the control of the control unit 304, the display device 50A displays an image CG representing the shovel 100 in a top view, and also displays the shovel 100 so as to surround the image CG. A line TBL representing the degree of stability of the behavior of 100 is displayed.

The line TBL represents the outer edge of the range where the stability moment is smaller than the overturning moment with respect to the position of the tip (bucket 6) of the attachment AT.

As shown in FIG. 9, when the attachment AT is stationary, the overturning moment of the shovel 100 depends only on the mass (weight) of the attachment AT. Therefore, the line TBL is displayed at a position relatively distant from the image CG of the shovel 100. Thereby, the user of the shovel 100 can judge that the degree of stability of the behavior of the shovel 100 is relatively high, and that the possibility of unstable behavior such as overturning or vibration of the shovel 100 is low.

On the other hand, as shown in FIG. 10, when the attachment AT is operating, the overturning moment of the shovel 100 depends on the mass (weight) of the attachment AT and the external force FE applied to the attachment AT, as described above. Therefore, the line TBL is displayed at a position relatively close to the image CG of the shovel 100. Accordingly, the user of the shovel 100 can determine that the stability of the behavior of the shovel 100 is relatively low, and that there is a high possibility that the shovel 100 will exhibit unstable behavior such as overturning or vibration.

Note that the display contents in FIGS. 9 and 10 may be displayed on a remote operation support device (display device) or a remote monitoring support device (display device). In this case, images corresponding to the display contents of FIGS. 9 and 10 may be generated by the excavator 100 and transmitted to the remote operation support device or the remote monitoring support device, or may be transmitted to the remote operation support device or the remote monitoring support device. may be generated. In the latter case, the functions of the calculation unit 301 and the control unit 304 may be transferred to a remote operation support device or a remote monitoring support device.

[Other embodiments]
The embodiments described above may be combined, modified or modified as appropriate.

For example, in the embodiment described above, the excavator 100 may be equipped with a bucket posture sensor that detects the posture angle of the bucket 6 and a bucket cylinder pressure sensor that detects the pressure of the oil chamber of the bucket cylinder 9. In this case, the calculation unit 301 may calculate the external force acting on the attachment AT (bucket 6), the overturning moment acting on the shovel 100, etc. using the outputs of the bucket posture sensor and the bucket cylinder pressure sensor. Further, in this case, the calculation unit 301 uses the method described above to control the external force acting on the attachment AT (bucket 6) or the shovel 100 only when an abnormality occurs in the bucket posture sensor or the bucket cylinder pressure sensor. The overturning moment, etc. may also be calculated.

In the above-described embodiments and modified examples, the control unit 304 does not adjust the regeneration flow rate of hydraulic oil from the bottom side oil chamber of the boom cylinder 7 to the rod side oil chamber of the arm cylinder 8 through the regeneration circuit 175La. The unstable behavior of the excavator 100 may be suppressed by the following method. For example, an electromagnetic relief valve that can forcibly discharge the hydraulic oil in the oil chamber on the bottom side of the boom cylinder 7 to the hydraulic oil tank T may be provided. As a result, when the overturning moment of the excavator 100 exceeds the stabilizing moment and there is a possibility that the behavior of the excavator 100 may become unstable, the control unit 304 operates the electromagnetic relief valve, and the bottom side of the boom cylinder 7 The hydraulic oil in the oil chamber can be drained. Therefore, the boom cylinder 7 can move in the retracting direction, that is, in the lowering direction of the boom 4 under the weight of the boom 4, and as a result, at least one of the dynamic disturbances that exert a dynamic overturning moment on the aircraft body can be removed. part is absorbed. Therefore, dynamic disturbances are less likely to be transmitted as a dynamic overturning moment to the machine body, and unstable behavior of the excavator 100 such as forward overturning (rear part lifting) and vibration can be suppressed. Further, the control unit 304 can suppress unstable behavior of the shovel 100 that occurs when the shovel 100 is not in an earth removal operation. In this case, the prediction unit 303 may predict whether there is a possibility that the behavior of the excavator 100 will become unstable, regardless of the operating states of the boom 4 and the arm 5. Thereby, the prediction unit 303 can predict whether or not there is a possibility that unstable behavior of the shovel 100 will occur at times other than when the shovel 100 is in an earth removal operation. In this case, the electromagnetic relief valve is provided closer to the control valve 175R than the hydraulic oil holding circuit 90 on the high-pressure hydraulic line between the oil chamber on the bottom side of the boom cylinder 7 and the control valve 175R in the control valve 17. It's okay to be hit. When operating the electromagnetic relief valve, the control unit 304 may also output a control command to the electromagnetic proportional valve 92 to cancel the function of the hydraulic oil holding circuit 90. Thereby, the function of the hydraulic oil holding circuit 90 and the function of the electromagnetic relief valve can be made compatible. For example, the electromagnetic relief valve is provided in the high pressure hydraulic line between the hydraulic oil holding circuit 90 and the control valve 17. Further, the electromagnetic relief valve may be provided in a portion of the high-pressure hydraulic line between the bottom-side oil chamber of the boom cylinder 7 and the control valve 175R in the control valve 17, which is built in the control valve 17. Further, the electromagnetic relief valve may be built into the control valve 175R.

Furthermore, in the embodiments and modifications described above, the prediction unit 303 may predict whether or not unstable behavior will occur in the excavator 100 using a method different from the above. For example, the prediction unit 303 may predict that unstable behavior will occur in the excavator 100 when the detected value of the boom bottom pressure by the boom bottom pressure sensor S7B exceeds a predetermined standard.

Furthermore, in the above-described embodiments and modifications, the control unit 304 controls the oil chamber from the bottom side oil chamber of the boom cylinder 7 to the rod side of the arm cylinder 8, regardless of the prediction result of the prediction unit 303, during the earth removal operation of the excavator 100. The regeneration flow rate of hydraulic oil to the oil chamber may be made smaller than the normal reference state. In this case, the prediction unit 303 may be omitted.

[Effect]
Next, the operation of the shovel 100 according to this embodiment will be explained.

In this embodiment, the excavator 100 includes a lower traveling body, an upper revolving body, a boom, an arm, a bucket, a first hydraulic cylinder, a second hydraulic cylinder, a hydraulic pump, a control valve, It includes a reproduction circuit and a control section. The undercarriage body is, for example, the undercarriage body 1. The upper revolving structure is, for example, the upper revolving structure 3. The boom is, for example, boom 4. The arm is, for example, arm 5. The bucket is, for example, bucket 6. The first hydraulic cylinder is, for example, the boom cylinder 7. The second hydraulic cylinder is, for example, the arm cylinder 8. The hydraulic pump is, for example, the main pump 14. The control valve is, for example, the control valve 17. The reproducing circuit is, for example, a reproducing circuit 175La. The control unit is, for example, the control unit 304. Specifically, the upper rotating body is rotatably mounted on the lower traveling body. The boom is also attached to the upper revolving structure. Further, the arm is attached to the tip of the boom. Further, the bucket is attached to the tip of the arm. A first hydraulic cylinder drives the boom. The second hydraulic cylinder also drives the arm. Further, the control valve supplies hydraulic oil supplied from the hydraulic pump to the first hydraulic cylinder and the second hydraulic cylinder. Further, the regeneration circuit regenerates hydraulic oil discharged from the first hydraulic cylinder into the second hydraulic cylinder when the boom is lowered and the arm is opened. Then, during the operation of discharging the contents of the bucket (earth removal operation), the control unit makes the regeneration flow rate to the second hydraulic cylinder by the regeneration circuit smaller than a predetermined reference state.

Thereby, the shovel 100 (control device) can suppress the regeneration flow rate from the first hydraulic cylinder to the second hydraulic cylinder accompanying the boom lowering operation and arm opening operation during the earth removal operation. Therefore, the excavator 100 can suppress the acceleration of the boom and arm during the earth removal operation, and as a result, the dynamic disturbance (external force) acting on the attachment (bucket) can be suppressed. Therefore, the shovel 100 can suppress unstable behavior during the earth removal operation. Moreover, by suppressing the regeneration flow rate from the hydraulic cylinder that drives the boom to the hydraulic cylinder that drives the arm, it is possible to suppress the acceleration of both the boom and the arm. Therefore, the shovel 100 can more efficiently suppress unstable behavior of the shovel 100 during the earth removal operation.

Furthermore, in the present embodiment, if there is a possibility that the excavator exhibits unstable behavior during the operation of discharging the contents of the bucket (during the earth removal operation), the control unit adjusts the above-mentioned regeneration flow rate from the reference state. You can also make it smaller.

Thereby, the shovel 100 can suppress the above-mentioned regeneration flow rate only when there is a possibility that unstable behavior will occur in the shovel during the earth removal operation. Therefore, unstable behavior of the shovel 100 can be suppressed while suppressing a decrease in the working efficiency of the shovel 100.

In addition, in this embodiment, the control unit controls the regeneration flow rate to be smaller than the reference state when the boom lowering operation and the arm opening operation are performed at the same time and there is a possibility that unstable behavior will occur in the excavator. You may.

Thereby, the shovel 100 can suppress the above-mentioned regeneration flow rate only when there is a possibility that the shovel 100 will exhibit unstable behavior during the earth removal operation. This is because the earth removal operation is often performed by simultaneously performing the boom lowering operation and the arm opening operation.

Furthermore, in the present embodiment, the control unit sets the regeneration flow rate to the reference state when there is no possibility of unstable behavior of the shovel during the operation of discharging the contents of the bucket (during the earth removal operation). It's okay.

Thereby, a decrease in the working efficiency of the shovel 100 can be suppressed.

In addition, in this embodiment, when there is no possibility of unstable behavior of the excavator, when the amount of contents in the bucket is relatively small, and when the orientation of the upper revolving body and the orientation of the lower traveling body is At least one of the cases where the difference is relatively large may be included.

Thereby, a decrease in the working efficiency of the shovel 100 can be suppressed.

Further, in the present embodiment, the excavator 100 may include a first attitude sensor, a second attitude sensor, a first pressure sensor, a second pressure sensor, and a calculation unit. The first attitude sensor is, for example, a boom attitude sensor S1. The second posture sensor is, for example, arm posture sensor S2. The first pressure sensor is, for example, a boom cylinder pressure sensor S7. The second pressure sensor is, for example, an arm cylinder pressure sensor S8. The calculation unit is, for example, the calculation unit 301. Specifically, the first attitude sensor may acquire data regarding the attitude state of the boom. Further, the second posture sensor may acquire data regarding the posture state of the arm. Further, the first pressure sensor may acquire data regarding the pressure of hydraulic fluid in the first hydraulic cylinder. Further, the second pressure sensor may acquire data regarding the pressure of hydraulic fluid in the second hydraulic cylinder. Further, the calculation unit may calculate the external force acting on the bucket based on the outputs of the first attitude sensor, the second attitude sensor, the first pressure sensor, and the second pressure sensor. Then, the control section may make the regeneration flow rate to the second hydraulic cylinder by the regeneration circuit smaller than the reference state based on the calculation result of the calculation section during the operation of discharging the contents of the bucket.

As a result, the excavator 100 (control device), for example, monitors the external force acting on the bucket and suppresses the regeneration flow rate by the regeneration circuit in accordance with the situation where the excavator may exhibit unstable behavior. be able to.

Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist described in the claims.

1 Lower traveling body 1ML Travel hydraulic motor 1MR Travel hydraulic motor 2 Swing mechanism 2M Swing hydraulic motor 3 Upper rotating body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 13, 13L, 13R Regulator 14, 14L, 14R Main pump 15 Pilot pump 17 Control valve 26 Operating device 29 Operating pressure sensor 30 Controller 50 Output device 50A Display device 50B Sound output device 52 Input device 60 Hydraulic control valve 90 Hydraulic oil holding circuit 100 Excavator 171, 172, 173, 174, 175L, 175R, 176L, 176R Control valve 175La Regeneration circuit 175Lb Regeneration throttle 175Lc Check valve 175Ra Regeneration circuit 175Rb Check valve 301 Arithmetic unit 302 Judgment unit 303 Prediction unit 304 Control unit AT Attachment HA Hydraulic actuator S1 Boom attitude sensor S2 Arm attitude Sensor S4 Aircraft tilt sensor S5 Turning state sensor S7 Boom cylinder pressure sensor S8 Arm cylinder pressure sensor

Claims (6)

a lower running body;
an upper rotating body rotatably mounted on the lower traveling body;
a boom attached to the upper revolving body;
an arm attached to the tip of the boom;
a bucket attached to the tip of the arm;
a first hydraulic cylinder that drives the boom;
a second hydraulic cylinder that drives the arm;
hydraulic pump and
a control valve that supplies hydraulic oil supplied from the hydraulic pump to the first hydraulic cylinder and the second hydraulic cylinder;
a regeneration circuit that regenerates hydraulic oil discharged from the first hydraulic cylinder into the second hydraulic cylinder when the boom lowering operation and the arm opening operation are performed at the same time;
a control unit that makes the regeneration flow rate to the second hydraulic cylinder by the regeneration circuit smaller than a predetermined reference state during the operation of discharging the contents of the bucket;
shovel. The control unit makes the regeneration flow rate smaller than the reference state if there is a possibility that unstable behavior will occur in the excavator during the operation of discharging the contents of the bucket.
The excavator according to claim 1. The control unit makes the regeneration flow rate smaller than the reference state when the boom lowering operation and the arm opening operation are performed at the same time and there is a possibility that unstable behavior will occur in the excavator. ,
The excavator according to claim 1 or 2. The control unit sets the regeneration flow rate to the reference state if there is no possibility that unstable behavior will occur in the shovel during the operation of discharging the contents of the bucket.
An excavator according to any one of claims 1 to 3. In the case where there is no possibility of unstable behavior occurring in the excavator, the amount of the stored material is relatively small, and the difference between the orientation of the upper rotating body and the orientation of the lower rotating body is relatively large. includes at least one of the cases where
The excavator according to claim 4. a first attitude sensor that acquires data regarding the attitude state of the boom;
a second posture sensor that acquires data regarding the posture state of the arm;
a first pressure sensor that acquires data regarding the pressure of hydraulic fluid in the first hydraulic cylinder;
a second pressure sensor that acquires data regarding the pressure of hydraulic fluid in the second hydraulic cylinder;
a calculation unit that calculates an external force acting on the bucket based on outputs of the first attitude sensor, the second attitude sensor, the first pressure sensor, and the second pressure sensor;
The control unit makes the regeneration flow rate to the second hydraulic cylinder by the regeneration circuit smaller than the reference state based on the calculation result of the calculation unit during the operation of discharging the contents of the bucket.
An excavator according to any one of claims 1 to 5.

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