JP2024094841A - Excavator - Google Patents

Abstract

The present invention provides a state in which movement of an actuator not related to an abnormality is permitted even when movement of an actuator related to an abnormality is not permitted.
[Solution] The excavator 100 includes a lower traveling body 1, an upper rotating body 3 rotatably mounted on the lower traveling body 1, a plurality of actuators, a plurality of electric operation devices used to operate the plurality of actuators, and a controller 30 that determines whether or not there is an abnormality in one of the plurality of electric operation devices. The controller 30 prohibits the movement of one actuator in response to the operation of one electric operation device determined to have an abnormality.
[Selected Figure] Figure 1

Description

This disclosure relates to a shovel.

Conventionally, there is known an excavator equipped with an electromagnetic proportional valve that is disposed in a pipeline between the end of a spool of a control valve that switches the flow of hydraulic oil flowing in and out of a hydraulic actuator and a pilot hydraulic pump, and that adjusts the pilot pressure acting on the end of the spool of the control valve (see Patent Document 1). In this excavator, an emergency stop valve for cutting off hydraulic pressure when an abnormality in the excavator is detected is disposed in the pipeline between the pilot hydraulic pump and the electromagnetic proportional valve.

JP 2019-206878 A

However, even if the emergency stop valve described above does not allow the movement of the actuator related to the abnormality, it cannot realize a state in which the movement of the actuator not related to the abnormality is allowed.

Therefore, even if the movement of the actuator related to the abnormality is not permitted, it is desirable to realize a state in which the movement of the actuator not related to the abnormality is permitted.

The excavator according to an embodiment of the present disclosure includes a lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, a plurality of actuators, a plurality of electric operating devices used to operate the plurality of actuators, and a control device that determines whether or not there is an abnormality in one of the plurality of electric operating devices, and the control device prohibits movement of one of the actuators in response to the operation of one of the electric operating devices that has been determined to have an abnormality.

The above-mentioned shovel can achieve a state in which actuator movement unrelated to the abnormality is permitted even when actuator movement related to the abnormality is not permitted.

FIG. 1 is a side view of a shovel according to an embodiment of the present disclosure. FIG. 2 is a top view of the shovel of FIG. 1 . FIG. 2 is a diagram showing a configuration example of a hydraulic system mounted on the excavator shown in FIG. FIG. 1 is a diagram of a portion of the hydraulic system for operation of the arm cylinder. FIG. 2 is a diagram of a portion of the hydraulic system involved in the operation of the boom cylinder. FIG. 2 is a diagram of a portion of a hydraulic system for operation of a bucket cylinder. FIG. 2 is a diagram of a portion of a hydraulic system relating to the operation of a swing hydraulic motor. FIG. 1 is a diagram of a portion of the hydraulic system relating to the operation of the left travel hydraulic motor. FIG. 1 is a diagram of a portion of the hydraulic system relating to the operation of the right travel hydraulic motor. FIG. 2 is a block diagram showing a configuration example of a controller. 13 is a block diagram showing details of a configuration example of an enable unit. FIG. FIG. 4 is a diagram illustrating an example of a relationship between a PWM signal and an enable command signal.

First, a shovel 100 as an excavator according to an embodiment of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is a side view of the shovel 100, and Figure 2 is a top view of the shovel 100.

In this embodiment, the lower traveling body 1 of the excavator 100 includes a crawler 1C. The crawler 1C is driven by a traveling hydraulic motor 2M as a traveling actuator mounted on the lower traveling body 1. Specifically, the crawler 1C includes a left crawler 1CL and a right crawler 1CR. The left crawler 1CL is driven by a left traveling hydraulic motor 2ML, and the right crawler 1CR is driven by a right traveling hydraulic motor 2MR.

The upper rotating body 3 is mounted on the lower traveling body 1 so as to be able to rotate via a rotation mechanism 2. The rotation mechanism 2 is driven by a rotation hydraulic motor 2A as a rotation actuator mounted on the upper rotating body 3. However, the rotation actuator may also be a rotation motor generator as an electric actuator.

A boom 4 is attached to the upper rotating body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5 as an end attachment. The boom 4, the arm 5, and the bucket 6 constitute an excavation attachment, which is an example of an attachment AT. The boom 4 is driven by a boom cylinder 7, the arm 5 is driven by an arm cylinder 8, and the bucket 6 is driven by a bucket cylinder 9. The boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 constitute an attachment actuator. The excavation attachment may be equipped with attitude sensors such as a boom angle sensor, an arm angle sensor, and a bucket angle sensor. In the example shown in Figures 1 and 2, the bucket 6 is an excavation bucket, but it may be a slope bucket, a skeleton bucket, or a (gravel removal bucket). The bucket 6 may also be equipped with a bucket tilt mechanism.

The boom angle sensor is attached to the boom 4 and detects the rotation angle of the boom 4 relative to the upper rotating body 3 (hereinafter, the "boom angle"). The boom angle is, for example, the angle formed by a straight line connecting both ends of the boom 4 (the center points of the connecting pins) with the rotation plane (plane perpendicular to the rotation axis) of the upper rotating body 3 in a side view. The boom angle sensor is, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU (Inertial Measurement Unit), or a combination thereof. The boom angle sensor may also be composed of a potentiometer using a variable resistor, a cylinder sensor that detects the stroke amount of a hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, or the like. The same applies to the arm angle sensor and the bucket angle sensor. A detection signal corresponding to the boom angle by the boom angle sensor is taken into the controller 30.

The arm angle sensor is attached to the arm 5 and detects the rotation angle of the arm 5 relative to the boom 4 (hereinafter, the "arm angle"). The arm angle is, for example, the angle between a line connecting both ends of the boom 4 (the center points of the connecting pin) and a line connecting both ends of the arm 5 (the center points of the connecting pin) in a side view. A detection signal corresponding to the arm angle by the arm angle sensor is input to the controller 30.

The bucket angle sensor is attached to the bucket 6 and detects the rotation angle of the bucket 6 relative to the arm 5 (hereinafter, "bucket angle"). The bucket angle is, for example, the angle formed by a line connecting the fulcrum (center point of the connecting pin) and the tip (cutting edge) of the bucket 6 with a line connecting both ends of the arm 5 (center points of the connecting pin) in a side view. A detection signal corresponding to the bucket angle by the bucket angle sensor is input to the controller 30. Note that the bucket angle sensor may be omitted. In this case, the controller 30 may estimate the bucket angle based on the output of the operation sensor 29RB (see FIG. 3).

The upper rotating body 3 is provided with a cabin 10 as a driver's cab, and is equipped with a power source such as an engine 11. The power source may be a hydrogen engine or an electric motor. Inside the cabin 10, an operating device 26, a controller 30, a gate lock lever 50, an operation method switching device SD, etc. are provided. The upper rotating body 3 is also equipped with a spatial recognition device 70 and a rotation angular velocity sensor S5, etc. A machine body inclination sensor may also be attached to the upper rotating body 3. In this document, for convenience, the side of the upper rotating body 3 to which the excavation attachment is attached is referred to as the front side, and the side to which the counterweight is attached is referred to as the rear side.

The spatial recognition device 70 is configured to recognize objects present in the three-dimensional space around the excavator 100. The spatial recognition device 70 includes, for example, an imaging device, a LIDAR, or any combination thereof. In this embodiment, the spatial recognition device 70 includes a forward sensor 70F attached to the front end of the upper surface of the cabin 10, a rear sensor 70B attached to the rear end of the upper surface of the upper rotating body 3, a left sensor 70L attached to the left end of the upper surface of the upper rotating body 3, and a right sensor 70R attached to the right end of the upper surface of the upper rotating body 3.

The machine body inclination sensor detects the inclination state of the machine body (upper rotating body 3 or lower running body 1) relative to the horizontal plane. The machine body inclination sensor detects, for example, the inclination angle around two axes in the fore-aft and lateral directions (hereinafter, "fore-aft inclination angle" and "lateral inclination angle") of the shovel 100 (i.e., upper rotating body 3). The machine body inclination sensor is, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an inertial measurement unit (IMU), or a combination thereof. The detection signal corresponding to the inclination angle (fore-aft inclination angle and lateral inclination angle) by the machine body inclination sensor is input to the controller 30.

The rotation angular velocity sensor S5 is configured to detect the rotation angular velocity of the upper rotating body 3. In this embodiment, the rotation angular velocity sensor S5 is, for example, an inertial measurement unit (IMU) that measures the attitude of the upper rotating body 3. The rotation angular velocity sensor S5 may also be a resolver or a rotary encoder, etc. The rotation angular velocity sensor S5 may detect the rotation speed. The rotation speed may be calculated from the rotation angular velocity.

The operating device 26 is a device used by an operator to operate the actuator. In this embodiment, the operating device 26 is an electric operating device. The operating device 26 includes, for example, an operating lever and an operating pedal. In this embodiment, the operating lever is an electric operating lever. The actuator includes at least one of a hydraulic actuator and an electric actuator.

The operation method switching device SD is configured to be able to switch the operation method of the operation lever. For example, the operation method switching device SD includes a push button switch provided on the right console in the cabin 10, and is configured to be able to switch the operation method of the operation lever between the first operation method and the second operation method each time the push button switch is pressed. For example, the first operation method is configured such that when the left operation lever 26L (see FIG. 3) is tilted forward, the arm 5 is opened, when the left operation lever 26L is tilted backward, the arm 5 is closed, when the left operation lever 26L is tilted left, a left turn is performed, and when the left operation lever 26L is tilted right, a right turn is performed. The first operation method is configured so that when the right operating lever 26R (see FIG. 3) is tilted forward, the boom 4 is lowered, when the right operating lever 26R is tilted backward, the boom 4 is raised, when the right operating lever 26R is tilted left, the bucket 6 is closed, and when the right operating lever 26R is tilted right, the bucket 6 is opened. On the other hand, the second operation method is configured so that when the left operating lever 26L (see FIG. 3) is tilted forward, a right turn is performed, when the left operating lever 26L is tilted backward, a left turn is performed, when the left operating lever 26L is tilted left, the arm 5 is opened, and when the left operating lever 26L is tilted right, the arm 5 is closed.

The operator of the excavator 100 may, for example, select the first operating method when performing excavation work using an excavation bucket, and may select the second operating method when performing gravel removal work using a skeleton bucket (gravel removal bucket).

The controller 30 is a control device for controlling the excavator 100. In this embodiment, the controller 30 is configured as a computer including a CPU, a volatile storage device, and a non-volatile storage device. The controller 30 reads out a program corresponding to each function from the non-volatile storage device, loads it into the volatile storage device, and causes the CPU to execute the corresponding process.

Next, referring to FIG. 3, an example of the configuration of a hydraulic system mounted on the excavator 100 will be described. FIG. 3 is a diagram showing an example of the configuration of a hydraulic system mounted on the excavator 100. In FIG. 3, the mechanical power transmission system, hydraulic oil line, pilot line, and electrical control system are indicated by double lines, solid lines, dashed lines, and dotted lines, respectively.

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

In FIG. 3, the hydraulic system is configured to circulate hydraulic oil from the main pump 14 driven by the engine 11 through a center bypass line 40 or a parallel line 42 to a hydraulic oil tank.

The engine 11 is an example of a power source for the shovel 100. In this embodiment, the engine 11 is, for example, a diesel engine that operates to maintain a predetermined rotation speed. The output shaft of the engine 11 is connected to the input shafts of the main pump 14 and the pilot pump 15. The power source for the shovel 100 may be a battery or a motor that runs on electricity from an external power source connected via a power cable.

The main pump 14 is configured to supply hydraulic oil to the control valve unit 17 via a hydraulic oil line. In this embodiment, the main pump 14 is a swash plate type variable displacement hydraulic pump.

The regulator 13 is configured to control the discharge volume of the main pump 14. In this embodiment, the regulator 13 controls the discharge volume of the main pump 14 by adjusting the swash plate tilt angle of the main pump 14 in response to a control command from the controller 30.

The pilot pump 15 is an example of a pilot pressure generating device that generates pilot pressure, which is a control pressure acting on each pilot port of the control valves 171 to 176, and is configured to be able to supply hydraulic oil to hydraulic control devices via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be realized by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to various hydraulic control devices via a pilot line, in addition to a function of supplying hydraulic oil to the control valve unit 17 via a hydraulic oil line. In this case, the pilot pump 15 may be omitted.

The control valve unit 17 is a hydraulic control device that controls the hydraulic system in the excavator 100. In this embodiment, the control valve unit 17 includes control valves 171 to 176. The control valve 175 includes a control valve 175L and a control valve 175R, and the control valve 176 includes a control valve 176L and a control valve 176R. The control valve unit 17 is configured to selectively supply hydraulic oil discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176. The control valves 171 to 176 control, for example, the flow rate of hydraulic oil flowing from the main pump 14 to the hydraulic actuators and the flow rate of hydraulic oil flowing from the hydraulic actuators to a hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, a left traveling hydraulic motor 2ML, a right traveling hydraulic motor 2MR, and a swing hydraulic motor 2A.

The operating device 26 is configured to allow an operator to operate the actuator. In this embodiment, the operating device 26 includes a hydraulic actuator operating device configured to allow an operator to operate the hydraulic actuator. Specifically, the hydraulic actuator operating device is configured to supply hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 using a solenoid valve. The pressure of the hydraulic oil supplied to each pilot port (pilot pressure) is a pressure that corresponds to the operation direction and operation amount of the operating device 26 corresponding to each hydraulic actuator.

The discharge pressure sensor 28 is configured to detect the discharge pressure of the main pump 14. In this embodiment, the discharge pressure sensor 28 outputs the detected value to the controller 30.

The operation sensor 29 is configured to detect the operation of the operation device 26 by the operator. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operation device 26 corresponding to each actuator, and outputs the detected value to the controller 30. In the illustrated example, the operation sensor 29 is an operation angle sensor that detects the operation angle of the operation lever.

The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates hydraulic oil to the hydraulic oil tank via the left center bypass line 40L or the left parallel line 42L, and the right main pump 14R circulates hydraulic oil to the hydraulic oil tank via the right center bypass line 40R or the right parallel line 42R.

The left center bypass line 40L is a hydraulic oil line that passes through the control valves 171, 173, 175L, and 176L arranged in the control valve unit 17. The right center bypass line 40R is a hydraulic oil line that passes through the control valves 172, 174, 175R, and 176R arranged in the control valve unit 17.

The control valve 171 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the left traveling hydraulic motor 2ML and to discharge the hydraulic oil discharged by the left traveling hydraulic motor 2ML to the hydraulic oil tank.

The control valve 172 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the right traveling hydraulic motor 2MR and to discharge the hydraulic oil discharged by the right traveling hydraulic motor 2MR to the hydraulic oil tank.

The control valve 173 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the swing hydraulic motor 2A and to discharge the hydraulic oil discharged by the swing hydraulic motor 2A to the hydraulic oil tank.

The control valve 174 is a spool valve that supplies the hydraulic oil discharged by the right main pump 14R to the bucket cylinder 9 and switches the flow of hydraulic oil to discharge the hydraulic oil in the bucket cylinder 9 to the hydraulic oil tank.

The control valve 175L is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the boom cylinder 7. The control valve 175R is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the boom cylinder 7 and to discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

The control valve 176L is a spool valve that supplies hydraulic oil discharged by the left main pump 14L to the arm cylinder 8 and switches the flow of hydraulic oil to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

The control valve 176R is a spool valve that supplies hydraulic oil discharged by the right main pump 14R to the arm cylinder 8 and switches the flow of hydraulic oil to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

The left parallel conduit 42L is a hydraulic oil line that runs parallel to the left center bypass conduit 40L. When the flow of hydraulic oil through the left center bypass conduit 40L is restricted or blocked by any of the control valves 171, 173, and 175L, the left parallel conduit 42L can supply hydraulic oil to a more downstream control valve. The right parallel conduit 42R is a hydraulic oil line that runs parallel to the right center bypass conduit 40R. When the flow of hydraulic oil through the right center bypass conduit 40R is restricted or blocked by any of the control valves 172, 174, and 175R, the right parallel conduit 42R can supply hydraulic oil to a more downstream control valve.

The regulator 13 includes a left regulator 13L and a right regulator 13R. The left regulator 13L controls the discharge volume of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to the discharge pressure of the left main pump 14L. Specifically, the left regulator 13L adjusts the swash plate tilt angle of the left main pump 14L in response to an increase in the discharge pressure of the left main pump 14L, for example, to reduce the discharge volume. The same is true for the right regulator 13R. This is to prevent the absorption power (absorption horsepower) of the main pump 14, which is expressed as the product of the discharge pressure and the discharge volume, from exceeding the output power (output horsepower) of the engine 11.

The operating device 26 includes a left operating lever 26L, a right operating lever 26R, and a travel operating device. The travel operating device includes a travel lever 26D and a travel pedal. The travel lever 26D includes a left travel lever 26DL and a right travel lever 26DR.

The left operating lever 26L is used for turning operations and operating the arm 5. When the left operating lever 26L is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 176. When the left operating lever 26L is operated in the left/right direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 173.

Specifically, when the left operating lever 26L is operated in the arm closing direction, it introduces hydraulic oil to the right pilot port of the control valve 176L and introduces hydraulic oil to the left pilot port of the control valve 176R. When the left operating lever 26L is operated in the arm opening direction, it introduces hydraulic oil to the left pilot port of the control valve 176L and introduces hydraulic oil to the right pilot port of the control valve 176R. When the left operating lever 26L is operated in the left turning direction, it introduces hydraulic oil to the left pilot port of the control valve 173, and when operated in the right turning direction, it introduces hydraulic oil to the right pilot port of the control valve 173.

In the example shown in FIG. 3, the left operating lever 26L functions as an arm operating lever when operated in the forward/rearward direction, and functions as a rotation operating lever when operated in the left/right direction.

The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever 26R is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 175. When it is operated in the left/right direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 174.

Specifically, when the right operating lever 26R is operated in the boom lowering direction, it introduces hydraulic oil to the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the boom raising direction, it introduces hydraulic oil to the right pilot port of the control valve 175L and also introduces hydraulic oil to the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the bucket closing direction, it introduces hydraulic oil to the right pilot port of the control valve 174, and when the right operating lever 26R is operated in the bucket opening direction, it introduces hydraulic oil to the left pilot port of the control valve 174.

In the example shown in FIG. 3, the right operating lever 26R functions as a boom operating lever when operated in the forward/backward direction, and functions as a bucket operating lever when operated in the left/right direction.

The travel lever 26D is used to operate the crawler 1C. Specifically, the left travel lever 26DL is used to operate the left crawler 1CL. The left travel lever 26DL may be configured to be linked to the left travel pedal. When the left travel lever 26DL is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 171. The right travel lever 26DR is used to operate the right crawler 1CR. The right travel lever 26DR may be configured to be linked to the right travel pedal. When the right travel lever 26DR is operated in the forward/backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 172.

The discharge pressure sensor 28 includes a discharge pressure sensor 28L and a discharge pressure sensor 28R. The discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L and outputs the detected value to the controller 30. The same is true for the discharge pressure sensor 28R.

The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the content of the operation of the left operating lever 26L in the forward/rearward direction by the operator, and outputs the detected value to the controller 30. The content of the operation includes, for example, the lever operation direction, the lever operation amount (lever operation angle), etc.

Similarly, the operation sensor 29LB detects the operation of the left operating lever 26L in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RA detects the operation of the right operating lever 26R in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RB detects the operation of the right operating lever 26R in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DL detects the operation of the left travel lever 26DL in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DR detects the operation of the right travel lever 26DR in the forward-backward direction by the operator, and outputs the detected value to the controller 30.

The controller 30 receives the output of the operation sensor 29, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The controller 30 also receives the output of the control pressure sensor 19 provided upstream of the orifice 18, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The orifice 18 includes a left orifice 18L and a right orifice 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

In the left center bypass line 40L, a left throttle 18L is disposed between the control valve 176L, which is the most downstream, and the hydraulic oil tank. Therefore, the flow of hydraulic oil discharged by the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L generates a control pressure for controlling the left regulator 13L. The left control pressure sensor 19L is a sensor for detecting this control pressure, and outputs the detected value to the controller 30. The controller 30 controls the discharge rate of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to this control pressure. The controller 30 reduces the discharge rate of the left main pump 14L as this control pressure increases, and increases the discharge rate of the left main pump 14L as this control pressure decreases. The discharge rate of the right main pump 14R is also controlled in a similar manner.

Specifically, as shown in FIG. 3, in the case of a standby state in which none of the hydraulic actuators in the excavator 100 are operated, the hydraulic oil discharged by the left main pump 14L passes through the left center bypass line 40L and reaches the left throttle 18L. The flow of hydraulic oil discharged by the left main pump 14L increases the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the allowable minimum discharge amount, suppressing the pressure loss (pumping loss) when the discharged hydraulic oil passes through the left center bypass line 40L. On the other hand, when any hydraulic actuator is operated, the hydraulic oil discharged by the left main pump 14L flows into the hydraulic actuator to be operated through the control valve corresponding to the hydraulic actuator to be operated. The flow of hydraulic oil discharged by the left main pump 14L reduces or eliminates the amount of hydraulic oil reaching the left throttle 18L, lowering the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 increases the discharge volume of the left main pump 14L, circulating sufficient hydraulic oil to the hydraulic actuator to be operated and ensuring the drive of the hydraulic actuator to be operated. The controller 30 also controls the discharge volume of the right main pump 14R in the same way.

With the above-mentioned configuration, the hydraulic system of FIG. 3 can suppress unnecessary energy consumption in the main pump 14 in a standby state. The unnecessary energy consumption includes pumping loss caused in the center bypass line 40 by the hydraulic oil discharged from the main pump 14. Furthermore, when operating a hydraulic actuator, the hydraulic system of FIG. 3 can reliably supply the necessary and sufficient hydraulic oil from the main pump 14 to the hydraulic actuator to be operated.

The boom cylinder 7 may be provided with a boom rod pressure sensor S7R and a boom bottom pressure sensor S7B. The arm cylinder 8 may be provided with an arm rod pressure sensor S8R and an arm bottom pressure sensor S8B. The bucket cylinder 9 may be provided with a bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B. The boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B are also referred to as "cylinder pressure sensors". The swing hydraulic motor 2A may be provided with a left swing pressure sensor S10L and a right swing pressure sensor S10R. The left traveling hydraulic motor 2ML may be provided with a reverse pressure sensor S11B and a forward pressure sensor S11F, and the right traveling hydraulic motor 2MR may be provided with a reverse pressure sensor S12B and a forward pressure sensor S12F. The left turning pressure sensor S10L, the right turning pressure sensor S10R, the reverse pressure sensor S11B, the forward pressure sensor S11F, the reverse pressure sensor S12B, and the forward pressure sensor S12F are also referred to as "motor pressure sensors."

The boom rod pressure sensor S7R detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom rod pressure"), and the boom bottom pressure sensor S7B detects the pressure in the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom bottom pressure"). The arm rod pressure sensor S8R detects the pressure in the rod side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm rod pressure"), and the arm bottom pressure sensor S8B detects the pressure in the bottom side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm bottom pressure"). The bucket rod pressure sensor S9R detects the pressure in the rod side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket rod pressure"), and the bucket bottom pressure sensor S9B detects the pressure in the bottom side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket bottom pressure"). The left swing pressure sensor S10L detects the pressure of the hydraulic oil in the left port of the swing hydraulic motor 2A. The right swing pressure sensor S10R detects the pressure of the hydraulic oil in the right port of the swing hydraulic motor 2A. The values detected by each sensor are sent to the controller 30. The movement of the hydraulic cylinder may be detected by a stroke sensor that detects the cylinder stroke amount.

A valve functioning as a master valve may be provided in the pilot line connecting the pilot pump 15 and the control valve unit 17. This valve is configured to switch between a closed state and an open state, and in the closed state, it can block the flow of hydraulic oil between the pilot pump 15 and the control valve unit 17, and in the open state, it can allow the flow of hydraulic oil between the pilot pump 15 and the control valve unit 17. In the illustrated example, the valve functioning as a master valve is called a gate lock valve 35, and is configured to switch between a closed state and an open state in response to a control command from the controller 30. The gate lock valve 35 may be disposed in the pilot line connecting the pilot pump 15 and each pilot port of the control valves 171 to 176 so that the strokes of each of the control valves 171 to 176 can be stopped individually. In addition, the determination of whether to switch the gate lock valve 35 from the open state to the closed state may be performed during the operation of the excavator 100, may be performed while the excavator 100 is stopped, or may be performed when a start flag is set. The start flag is set, for example, when the operating device 26 is operated or when the engine 11 is started.

A gate lock lever 50 may also be provided inside the cabin 10. The gate lock lever 50 is a device that switches the state of the shovel 100. In the illustrated example, the gate lock lever 50 has a locked state in which the shovel 100 is in an unworkable state, and an unlocked state in which the shovel 100 is in a workable state. The "workable state" means a state in which the operator can operate the shovel 100, and the "unworkable state" means a state in which the operator cannot operate the shovel 100. The gate lock lever 50 outputs a signal indicating its current state to the controller 30. The controller 30 repeatedly monitors (checks) the state of the gate lock lever 50 at a predetermined cycle.

Specifically, the operator unlocks the gate lock lever 50 by pulling up the gate lock lever 50 provided at the front left end of the driver's seat, and locks the gate lock lever 50 by pushing down the gate lock lever 50. In the unlocked state, the gate lock lever 50 blocks the entrance to the cabin 10 to restrict the operator from exiting the cabin 10, while enabling operation by the operating device 26 to allow the operator to operate the shovel 100. On the other hand, in the locked state, the gate lock lever 50 opens the entrance to the cabin 10 to allow the operator to exit the cabin 10, while disabling operation by the operating device 26 to prevent the operator from operating the shovel 100.

The gate lock lever 50 may be configured to close the gate lock valve 35 in the locked state and open the gate lock valve 35 in the unlocked state. In this case, the operator can manually switch the gate lock lever 50 between the locked state and the unlocked state to switch the gate lock valve 35 between the open state and the closed state. Specifically, the gate lock valve 35 is a switching valve provided in a pipeline between the pilot pump 15 and the control valve unit 17. In the example shown in FIG. 3, the gate lock valve 35 is an electromagnetic valve that operates in response to a control command from the controller 30. In the example shown in FIG. 3, the gate lock valve 35 is mechanically connected to the gate lock lever 50 and configured to operate in conjunction with the manual operation of the gate lock lever 50. In addition, the control valve unit 17 includes control valves 171 to 176 that control the flow of hydraulic oil between the main pump 14 and various hydraulic actuators. When the gate lock valve 35 is in a closed state, it can block the flow of hydraulic oil between the pilot pump 15 and each pilot port of the control valves 171 to 176 (blocking hydraulic pressure) and disable operation by the operating device 26. When the gate lock valve 35 is in an open state, it can allow the flow of hydraulic oil between the pilot pump 15 and each pilot port of the control valves 171 to 176 and enable operation by the operating device 26.

Next, the configuration for the controller 30 to operate the actuators will be described with reference to Figures 4A to 4F. Figures 4A to 4F are diagrams of parts of the hydraulic system. Specifically, Figure 4A is a diagram of the hydraulic system portion related to the operation of the arm cylinder 8, and Figure 4B is a diagram of the hydraulic system portion related to the operation of the boom cylinder 7. Figure 4C is a diagram of the hydraulic system portion related to the operation of the bucket cylinder 9, and Figure 4D is a diagram of the hydraulic system portion related to the operation of the swing hydraulic motor 2A. Figure 4E is a diagram of the hydraulic system portion related to the operation of the left traveling hydraulic motor 2ML, and Figure 4F is a diagram of the hydraulic system portion related to the operation of the right traveling hydraulic motor 2MR.

As shown in Figures 4A to 4F, the hydraulic system includes a solenoid valve 31 and a pressure sensor 32. The solenoid valve 31 includes solenoid valves 31AL to 31FL and solenoid valves 31AR to 31FR. The pressure sensor 32 includes pressure sensors 32AL to 32FL and pressure sensors 32AR to 32FR.

The solenoid valve 31 is disposed in a pipe connecting the pilot pump 15 and the pilot port of the corresponding control valve in the control valve unit 17, and is configured to change the flow area of the pipe by changing the opening area. In this embodiment, the solenoid valve 31 is an electromagnetic proportional valve and operates in response to a control command output by the controller 30. Specifically, the solenoid valve 31 is driven by a current supplied through a current output unit 30F (see FIG. 5) that operates in response to a control command (control signal) output by the controller 30. The solenoid valve 31 may be configured to detect the value of the supplied current (current value) and output the detected value to the controller 30. That is, the solenoid valve 31 may also be configured to function as a current sensor. The controller 30 may be configured to feedback control the solenoid valve 31 based on this detection value. Therefore, the controller 30 can supply the pilot oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the solenoid valve 31 in response to the operation of the operating device 26 by the operator or regardless of the operation of the operating device 26 by the operator. Then, the controller 30 can apply the pilot pressure generated by the solenoid valve 31 to the pilot port of the corresponding control valve.

The pressure sensor 32 is configured to detect the magnitude of the pilot pressure generated by the solenoid valve 31. The pressure sensor 32 is configured to output the detected value to the controller 30.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a specific operating device 26 not only when an operation is being performed on the specific operating device 26, but also when no operation is being performed on the specific operating device 26. Furthermore, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operating device 26 even when an operation is being performed on the specific operating device 26. Furthermore, the controller 30 can feedback control the pilot pressure generated by the solenoid valve 31 based on the output of the pressure sensor 32.

For example, as shown in FIG. 4A, the left operating lever 26L is used to operate the arm 5. Specifically, the left operating lever 26L uses pilot oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 176. More specifically, when the left operating lever 26L is operated in the arm closing direction (rearward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. This pilot pressure is detected by the pressure sensor 32AL. Also, when the left operating lever 26L is operated in the arm opening direction (forward), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R. This pilot pressure is detected by the pressure sensor 32AR.

The operation device 26 is provided with a switch SW. In this embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is an MC switch (push button switch) provided at the tip of the left operation lever 26L. The operator can operate the left operation lever 26L while pressing the switch SW1. The switch SW1 may be provided on the right operation lever 26R or at another position in the cabin 10. The switch SW2 is an MC switch (push button switch) provided at the tip of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 may be provided on the right travel lever 26DR or at another position in the cabin 10.

The operation sensor 29LA detects the forward/rearward operation of the left operating lever 26L by the operator and outputs the detected value to the controller 30.

The solenoid valve 31AL operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL. The solenoid valve 31AR operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR. The solenoid valve 31AL can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be stopped at any valve position. Similarly, the solenoid valve 31AR can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be stopped at any valve position.

With this configuration, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL in response to the arm closing operation by the operator. The controller 30 can also supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL, regardless of the arm closing operation by the operator. In other words, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or regardless of the arm closing operation by the operator. In this way, the solenoid valve 31AL functions as an "arm solenoid valve" or an "arm closing solenoid valve".

In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR in response to the arm opening operation by the operator. In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR, regardless of the arm opening operation by the operator. In other words, the controller 30 can open the arm 5 in response to the arm opening operation by the operator or regardless of the arm opening operation by the operator. In this way, the solenoid valve 31AR functions as an "arm solenoid valve" or an "arm opening solenoid valve".

In addition, with this configuration, even if the operator is performing an arm closing operation, the controller 30 can, if necessary, reduce the pilot pressure acting on the pilot ports on the closing side of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) to forcibly stop the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

Alternatively, even if the operator is performing an arm closing operation, the controller 30 may, if necessary, control the solenoid valve 31AR to increase the pilot pressure acting on the opening pilot port of the control valve 176 (the right pilot port of control valve 176L and the left pilot port of control valve 176R) opposite the closing pilot port of the control valve 176, and forcibly return the control valve 176 to the neutral position, thereby forcibly stopping the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

Although the following explanation with reference to Figures 4B to 4F is omitted, the same applies to the case where the operation of the boom 4 is forcibly stopped when the operator is performing a boom-raising or boom-lowering operation, the case where the operation of the bucket 6 is forcibly stopped when the operator is performing a bucket-closing or bucket-opening operation, and the case where the rotation operation of the upper rotating body 3 is forcibly stopped when the operator is performing a rotation operation. The same also applies to the case where the traveling operation of the lower traveling body 1 is forcibly stopped when the operator is performing a traveling operation.

In addition, in order to improve the responsiveness of arm operations (arm closing operation and arm opening operation), the controller 30 may be configured to apply a small pilot pressure to the pilot ports on both sides of the control valve 176 before the arm operation is performed. The same applies to other operations such as boom operations (boom raising operation and boom lowering operation). In other words, the controller 30 can improve the responsiveness of the hydraulic actuator by using more pilot oil.

As shown in FIG. 4B, the right operating lever 26R is used to operate the boom 4. Specifically, the right operating lever 26R uses pilot oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 175. More specifically, when the right operating lever 26R is operated in the boom-up direction (rearward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. This pilot pressure is detected by the pressure sensor 32BL. When the right operating lever 26R is operated in the boom-down direction (forward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R. This pilot pressure is detected by the pressure sensor 32BR.

The operation sensor 29RA detects the forward/rearward operation of the right operating lever 26R by the operator and outputs the detected value to the controller 30.

The solenoid valve 31BL operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL. The solenoid valve 31BR operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR. The solenoid valve 31BL can adjust the pilot pressure so that the control valves 175L and 175R can be stopped at any valve position. The solenoid valve 31BR can also adjust the pilot pressure so that the control valve 175R can be stopped at any valve position.

With this configuration, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL in response to the boom-raising operation by the operator. The controller 30 can also supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL, regardless of the boom-raising operation by the operator. In other words, the controller 30 can raise the boom 4 in response to the boom-raising operation by the operator or regardless of the boom-raising operation by the operator. In this way, the solenoid valve 31BL functions as a "boom solenoid valve" or a "boom-raising solenoid valve".

In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR in response to the boom lowering operation by the operator. In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR, regardless of the boom lowering operation by the operator. In other words, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator, or regardless of the boom lowering operation by the operator. In this way, the solenoid valve 31BR functions as a "boom solenoid valve" or a "boom lowering solenoid valve".

As shown in FIG. 4C, the right operating lever 26R is also used to operate the bucket 6. Specifically, the right operating lever 26R uses pilot oil discharged by the pilot pump 15 to apply pilot pressure corresponding to left-right operation to the pilot port of the control valve 174. More specifically, when the right operating lever 26R is operated in the bucket closing direction (left direction), it applies pilot pressure corresponding to the amount of operation to the left pilot port of the control valve 174. This pilot pressure is detected by the pressure sensor 32CL. Also, when the right operating lever 26R is operated in the bucket opening direction (right direction), it applies pilot pressure corresponding to the amount of operation to the right pilot port of the control valve 174. This pilot pressure is detected by the pressure sensor 32CR.

The operation sensor 29RB detects the left/right operation of the right operating lever 26R by the operator and outputs the detected value to the controller 30. Note that if the bucket angle sensor is omitted, the controller 30 may estimate the bucket angle based on the output of the operation sensor 29RB.

The solenoid valve 31CL operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL. The solenoid valve 31CR operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR. The solenoid valve 31CL can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position. Similarly, the solenoid valve 31CR can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position.

With this configuration, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL in response to the bucket closing operation by the operator. The controller 30 can also supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL, regardless of the bucket closing operation by the operator. In other words, the controller 30 can close the bucket 6 in response to the bucket closing operation by the operator, or regardless of the bucket closing operation by the operator. In this way, the solenoid valve 31CL functions as a "bucket solenoid valve" or a "bucket closing solenoid valve".

In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR in response to the bucket opening operation by the operator. In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR, regardless of the bucket opening operation by the operator. In other words, the controller 30 can open the bucket 6 in response to the bucket opening operation by the operator, or regardless of the bucket opening operation by the operator. In this way, the solenoid valve 31CR functions as a "solenoid valve for bucket" or a "solenoid valve for bucket opening".

As shown in FIG. 4D, the left operating lever 26L is also used to operate the turning mechanism 2. Specifically, the left operating lever 26L uses pilot oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the left and right direction to the pilot port of the control valve 173. More specifically, when the left operating lever 26L is operated in the left turning direction (left direction), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 173. This pilot pressure is detected by the pressure sensor 32DL. Also, when the left operating lever 26L is operated in the right turning direction (right direction), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 173. This pilot pressure is detected by the pressure sensor 32DR.

The operation sensor 29LB detects the left/right operation of the left operating lever 26L by the operator and outputs the detected value to the controller 30.

The solenoid valve 31DL operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL. The solenoid valve 31DR operates in response to a control command output by the controller 30. It adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR. The solenoid valve 31DL can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position. Similarly, the solenoid valve 31DR can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position.

With this configuration, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL in response to a left turning operation by the operator. The controller 30 can also supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL, regardless of a left turning operation by the operator. In other words, the controller 30 can rotate the turning mechanism 2 to the left in response to a left turning operation by the operator or regardless of a left turning operation by the operator. In this way, the solenoid valve 31DL functions as a "swing solenoid valve" or a "left turning solenoid valve".

In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR in response to a right turning operation by the operator. In addition, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR, regardless of a right turning operation by the operator. In other words, the controller 30 can rotate the turning mechanism 2 to the right in response to a right turning operation by the operator, or regardless of a right turning operation by the operator. In this way, the solenoid valve 31DR functions as a "swing solenoid valve" or a "right turning solenoid valve".

As shown in FIG. 4E, the left travel lever 26DL is used to operate the left crawler 1CL. Specifically, the left travel lever 26DL uses pilot oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 171. More specifically, when the left travel lever 26DL is operated in the forward direction (forward direction), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 171. This pilot pressure is detected by the pressure sensor 32EL. When the left travel lever 26DL is operated in the reverse direction (rearward direction), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 171. This pilot pressure is detected by the pressure sensor 32ER.

The operation sensor 29DL electrically detects the forward/rearward operation of the left travel lever 26DL by the operator and outputs the detected value to the controller 30.

The solenoid valve 31EL operates in response to a control command output by the controller 30. The solenoid valve 31EL adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL. The solenoid valve 31ER operates in response to a control command output by the controller 30. The solenoid valve 31ER adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER. The solenoid valves 31EL and 31ER can adjust the pilot pressure so that the control valve 171 can be stopped at any valve position.

With this configuration, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL, regardless of the left forward movement operation by the operator. In other words, the left crawler 1CL can be moved forward. Also, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER, regardless of the left reverse movement operation by the operator. In other words, the left crawler 1CL can be moved backward. In this way, the solenoid valve 31EL functions as a "left running solenoid valve" or a "left forward running solenoid valve", and the solenoid valve 31ER functions as a "left running solenoid valve" or a "left reverse running solenoid valve".

Also, as shown in FIG. 4F, the right travel lever 26DR is used to operate the right crawler 1CR. Specifically, the right travel lever 26DR uses pilot oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 172. More specifically, when the right travel lever 26DR is operated in the forward direction (forward direction), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 172. This pilot pressure is detected by the pressure sensor 32FL. Also, when the right travel lever 26DR is operated in the reverse direction (rearward direction), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 172. This pilot pressure is detected by the pressure sensor 32FR.

The operation sensor 29DR electrically detects the forward/rearward operation of the right travel lever 26DR by the operator and outputs the detected value to the controller 30.

The solenoid valve 31FL operates in response to a control command output by the controller 30. The solenoid valve 31FL adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FL. The solenoid valve 31FR operates in response to a control command output by the controller 30. The solenoid valve 31FR adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FR. The solenoid valves 31FL and 31FR can adjust the pilot pressure so that the control valve 172 can be stopped at any valve position.

With this configuration, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FL, regardless of the right forward movement operation by the operator. In other words, the right crawler 1CR can be moved forward. Also, the controller 30 can supply pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FR, regardless of the right reverse movement operation by the operator. In other words, the right crawler 1CR can be moved backward. In this way, the solenoid valve 31FL functions as a "right running solenoid valve" or a "right forward running solenoid valve", and the solenoid valve 31FR functions as a "right running solenoid valve" or a "right reverse running solenoid valve".

The excavator 100 may also be configured to automatically operate the bucket tilt mechanism. In this case, the hydraulic system portion related to the bucket tilt cylinder that constitutes the bucket tilt mechanism may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7, etc.

In addition, each control valve may be configured as an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electrical signal from the controller 30 that corresponds to the amount of operation of the electric control lever.

Next, an example of the configuration of the controller 30 will be described with reference to FIG. 5. FIG. 5 is a block diagram showing an example of the configuration of the controller 30.

In the excavator 100, the operator can stop the movement of all the actuators by manually operating the gate lock lever 50. Furthermore, when the controller 30 detects an abnormality in the operation device 26, it can stop the movement of all the actuators by closing the gate lock valve 35. However, rather than stopping all the actuators, the operator may wish to operate other actuators that are not related to the abnormality while preventing the operation of actuators related to the abnormality. For example, when an abnormality is detected in the swing operation lever, the operator may wish to stop the movement of the swing hydraulic motor 2A and then operate the traveling hydraulic motor 2M in order to move the excavator 100 to a location suitable for repairs.

To deal with such cases, the excavator 100 may be provided with multiple gate lock valves 35 that are individually arranged in the pipelines (pilot lines) between the pilot pump 15 and each pilot port of the control valves 171 to 176. However, such a configuration may result in an increase in the number of parts, which may increase the manufacturing cost of the excavator 100.

Therefore, in this embodiment, the controller 30 is able to individually cut off the current output to operate each actuator, thereby achieving functionality similar to that achieved by a configuration including multiple gate lock valves 35.

In the example shown in FIG. 5, the controller 30 includes a fault determination unit 30A, a control unit 30B, an input unit 30C, a conversion unit 30D, an enable unit 30E, and a current output unit 30F.

The fault determination unit 30A and the control unit 30B are composed of software (programs) stored in a non-volatile storage device such as a ROM or NVRAM. The controller 30 reads out the software corresponding to the fault determination unit 30A and the control unit 30B from the non-volatile storage device and loads it into the RAM, and causes the CPU to execute the corresponding processing. The input unit 30C, the conversion unit 30D, and the current output unit 30F are composed of electronic circuits, and the enable unit 30E is composed of an FPGA (Field-Programmable Gate Array). However, the fault determination unit 30A and the control unit 30B may be composed of an electronic circuit or may be composed of firmware such as an FPGA. The input unit 30C, the conversion unit 30D, and the current output unit 30F may be composed of software or may be composed of an FPGA. The enable unit 30E may be composed of software or may be composed of an electronic circuit. In addition, each of the fault determination unit 30A, the control unit 30B, the input unit 30C, the conversion unit 30D, the enable unit 30E, and the current output unit 30F may be configured with a combination of at least two of software, electronic circuits, firmware, etc.

In addition, in the example shown in FIG. 5, for clarity, each of the enable unit 30E and the current output unit 30F is shown as one block, but in reality, the controller 30 has a number of enable units 30E corresponding to the number of solenoid valves 31 and a number of current output units 30F corresponding to the number of solenoid valves 31. For example, the enable unit 30E includes an arm closing enable unit corresponding to the solenoid valve 31AL (see FIG. 4A) related to the arm closing operation, an arm opening enable unit corresponding to the solenoid valve 31AR (see FIG. 4A) related to the arm opening operation, a boom raising enable unit corresponding to the solenoid valve 31BL (see FIG. 4B) related to the boom raising operation, and a boom lowering enable unit corresponding to the solenoid valve 31BR (see FIG. 4B) related to the boom lowering operation. However, the arm closing enable unit and the arm opening enable unit may be integrated into one arm operation enable unit. The same applies to the boom operation enable unit, the bucket operation enable unit, the swing operation enable unit, and the travel operation enable unit. In addition, the arm operation enable unit and the swing operation enable unit may be integrated into a single right operation lever enable unit, and the boom operation enable unit and the bucket operation enable unit may be integrated into a single left operation lever enable unit. The same applies to the current output unit 30F.

The fault determination unit 30A is configured to determine whether or not there is an abnormality in the operation device 26. In the present disclosure, the abnormality in the operation device 26 includes not only an abnormality in the operation device 26 itself, but also an abnormality in each of a plurality of components (such as a solenoid valve, a control valve, and a pressure sensor) for realizing the movement of the actuator in response to the operation of the operation device 26. For example, even if there is no abnormality in the boom operation lever itself, if there is an abnormality in the solenoid valve 31BL, and therefore the boom cylinder 7 cannot be operated appropriately in response to the operation of the boom operation lever, the fault determination unit 30A is configured to determine that there is an abnormality in the boom operation lever for convenience's sake. In other words, when there is an abnormality in a part of the boom operation system, the controller 30 is configured to determine that there is an abnormality in the boom operation lever for convenience, even if there is no abnormality in the boom operation lever itself. In the illustrated example, the fault determination unit 30A is configured to continuously determine whether or not there is an abnormality while power is being supplied to the controller 30. However, the failure determination unit 30A may be configured to perform the determination only for a specified period of time, such as while the engine 11 is running or while the gate lock valve 35 is in an open state.

The control unit 30B is configured to generate a control signal for operating the actuator in response to the operation of the operating device 26.

The input unit 30C is configured to convert information output by a sensor that detects the operation of the operating device 26 into information that can be processed by the controller 30. In the illustrated example, the input unit 30C is an electronic circuit that converts analog data output by the operation sensor 29 into digital data that can be processed by each of the failure determination unit 30A and the control unit 30B.

The conversion unit 30D is configured to convert information output by various sensors into information that can be processed by the controller 30. In the illustrated example, the conversion unit 30D is an analog-to-digital conversion circuit (electronic circuit) that converts analog data (current value) output by the solenoid valve 31 functioning as a current sensor and analog data (pressure value) output by the pressure sensor 32, etc., into digital data that can be processed by the failure determination unit 30A. Note that the value of the current (current value) supplied to the solenoid valve 31 may be detected by a current sensor independent of the solenoid valve 31.

The fault determination unit 30A determines whether or not there is an abnormality in the operating device 26 based on the digital data output by the input unit 30C and the digital data output by the conversion unit 30D. The fault determination unit 30A also generates an enable command signal based on the determination result and outputs the enable command signal to the enable unit 30E. In the illustrated example, the enable command signal is a binary signal that alternatively takes a voltage level (ON level) representing "ON" and a voltage level (OFF level) representing "OFF". The fault determination unit 30A continuously outputs an ON level enable command signal until it determines that there is an abnormality in the operating device 26, and at the point in time when it determines that there is an abnormality, it switches the ON level enable command signal to an OFF level enable command signal. The control unit 30B also generates a control signal for the current output unit 30F (enable unit 30E) based on the digital data output by the conversion unit 30D.

The enable unit 30E is a safety circuit that transmits an appropriate control signal generated by the control unit 30B to the current output unit 30F, while suppressing or preventing an inappropriate control signal generated by the control unit 30B from being transmitted to the current output unit 30F. In other words, the enable unit 30E is a monitoring circuit that monitors the appropriateness of the control signal generated by the control unit 30B. In the illustrated example, the enable unit 30E is configured to be able to control the output (transmission) of the control signal generated by the control unit 30B to the current output unit 30F.

Figure 6 is a block diagram showing details of an example configuration of the enable unit 30E. In the example shown in Figure 6, the enable unit 30E is configured to receive as inputs a control signal generated by the control unit 30B and an enable command signal generated by the fault determination unit 30A, and output a PWM signal to the current output unit 30F. Specifically, the enable unit 30E includes a PWM output circuit 30E1, an interlock circuit 30E2, and a logical product circuit (AND circuit 30E3).

The PWM output circuit 30E1 is an example of a circuit for converting a control signal generated by the control unit 30B into a signal that can be processed by the current output unit 30F. In the illustrated example, the PWM output circuit 30E1 generates a PWM signal based on a control signal from the control unit 30B, and outputs the generated PWM signal to the AND circuit 30E3. Note that the control unit 30B may be configured to output a PWM signal as a control signal. In this case, the PWM output circuit 30E1 is omitted.

The interlock circuit 30E2 is configured to suppress or prevent an inappropriate PWM signal generated by the PWM output circuit 30E1 from being transmitted to the current output unit 30F. In the illustrated example, the interlock circuit 30E2 generates an enable signal based on an enable command signal from the fault determination unit 30A, and outputs the generated enable signal to the AND circuit 30E3. Specifically, the enable signal is a binary signal that alternatively takes an H (High) level and an L (Low) level. The interlock circuit 30E2 outputs an H-level enable signal to the AND circuit 30E3 while an ON-level enable command signal is input, and outputs an L-level enable signal to the AND circuit 30E3 while an OFF-level enable command signal is input. The enable command signal generated by the fault determination unit 30A may be directly input to the AND circuit 30E3. In this case, the interlock circuit 30E2 is omitted.

The AND circuit 30E3 is configured to transmit the input signal to the current output unit 30F when a certain condition is satisfied. In the illustrated example, while an H-level enable signal is being input, the AND circuit 30E3 outputs the PWM signal input from the PWM output circuit 30E1 directly to the current output unit 30F, and while an L-level enable signal is being input, the AND circuit 30E3 outputs a PWM signal with a duty ratio (pulse width/period) of 0% (all output pulses are OFF) regardless of the PWM signal input from the PWM output circuit 30E1.

Figure 7 shows an example of the relationship between the PWM signal (input) input to the AND circuit 30E3, the enable command signal, and the PWM signal (output) output from the AND circuit 30E3.

Figure 7 shows that the PWM signal (input) and the PWM signal (output) have the same waveform until the enable command signal is switched to the OFF level at time t1, but after the enable command signal is switched to the OFF level at time t1, the duty ratio of the PWM signal (output) becomes 0%.

The current output unit 30F is an electronic circuit configured to supply a current corresponding to the control signal generated by the control unit 30B to the solenoid valve 31. In the illustrated example, the current output unit 30F supplies a current to the solenoid valve 31 in response to the PWM signal output by the enable unit 30E. Specifically, it supplies a current of a magnitude corresponding to the duty ratio of the PWM signal to the solenoid valve 31. The magnitude of the current supplied to the solenoid valve 31 increases as the duty ratio of the PWM signal increases.

With the above-described configuration, when the controller 30 detects an abnormality in a specific operating device 26, it can prohibit the movement of a specific actuator corresponding to that specific operating device 26. Furthermore, the controller 30 may or may not prohibit the movement of actuators other than that specific actuator, i.e., actuators corresponding to operating devices 26 for which no abnormality has been detected.

Note that prohibiting the movement of an actuator includes stopping the movement of an actuator that is currently operating, and preventing the operation of an actuator that is not currently operating.

For example, when the swing operation lever is operated in the left swing direction, the failure determination unit 30A of the controller 30 determines whether or not there is an abnormality in the swing operation lever based on the operation signal from the operation sensor 29LB (see FIG. 3), the pressure value from the pressure sensor 32DL (see FIG. 4D) that detects the pilot pressure acting on the left pilot port of the control valve 173, and the current value from the solenoid valve 31DL (see FIG. 4D). Note that in this disclosure, an abnormality in the swing operation lever includes not only an abnormality in the swing operation lever itself, but also an abnormality in each of the multiple components (swing hydraulic motor 2A, solenoid valve 31DL, solenoid valve 31DR, pressure sensor 32DL, pressure sensor 32DR, control valve 173, etc.) that realize the movement of the swing hydraulic motor 2A in response to the operation of the swing operation lever. For example, even if there is no abnormality in the swing operation lever itself, if there is an abnormality in the pressure sensor 32DL and the swing hydraulic motor 2A cannot be operated appropriately in response to the operation of the swing operation lever, the failure determination unit 30A is configured to determine that there is an abnormality in the swing operation lever.

The malfunction determination unit 30A may determine the presence or absence of an abnormality using the pressure value from the left turning pressure sensor S10L instead of the pressure value from the pressure sensor 32DL, or may additionally determine the presence or absence of an abnormality using the pressure value from the left turning pressure sensor S10L. The malfunction determination unit 30A may also determine the presence or absence of an abnormality by alternatively or additionally using the detection value of a sensor other than the left turning pressure sensor S10L.

The fault determination unit 30A does not need to specify which of the swing operation lever, the pressure sensor 32DL, the solenoid valve 31DL, etc. is abnormal, but only needs to determine whether there is an abnormality in the movement of the swing hydraulic motor 2A in response to the operation of the swing operation lever, that is, whether there is an abnormality in the swing operation system as a whole, but may specify which of the swing operation lever, the pressure sensor 32DL, the solenoid valve 31DL, etc. is abnormal. For example, if the fault determination unit 30A can estimate the occurrence of a disconnection between the operation device 26 and the controller 30, it may output this to a display device or the like to inform the operator. An abnormality in the operation device 26 itself is detected, for example, when the value of the operation signal deviates from a preset range, or when no change is observed in the operation signal despite fluctuations in the output of the pressure sensor 32, etc. Alternatively, an abnormality in the pressure sensor 32 itself is detected, for example, when the pressure value deviates from a preset range, or when no change is observed in the pressure value despite fluctuations in the operation signal, etc. Similarly, an abnormality in the solenoid valve 31 itself is detected, for example, when the current value deviates from a preset range, or when no change is observed in the current value despite fluctuations in the operation signal, etc. The operation device 26 may be configured to output a predetermined signal pattern even when the operation device 26 is not being operated. This is because it makes it easier to detect abnormalities. That is, this is because it makes it possible to detect abnormalities in the operation device 26 itself even when the operation device 26 is not being operated. The failure determination unit 30A may also be configured to ignore momentary abnormalities in the operation signal. This is to suppress erroneous detection of abnormalities. Specifically, when an abnormal value is continuously output for a predetermined time, or when an abnormal value is repeatedly output a predetermined number of times or more, the failure determination unit 30A may detect the state as an abnormality in the operation device 26. The same applies when a mechanical or electrical abnormality occurs inside the operation device 26, when an abnormality occurs in the pressure sensor 32, or when an abnormality occurs in the solenoid valve 31, etc.

In the illustrated example, when the fault determination unit 30A determines that there is an abnormality in the swing operation lever, it outputs an enable command signal of OFF level to the swing operation enable unit, which is one of the enable units 30E, and stops the supply of current to the solenoid valves 31DL and 31DR through the swing current output unit, which is one of the current output units 30F, thereby prohibiting the movement of the swing hydraulic motor 2A. On the other hand, even when the movement of the swing hydraulic motor 2A is prohibited, the fault determination unit 30A does not prohibit the movement of other actuators such as the traveling hydraulic motor 2M, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 until it determines that there is an abnormality in each of them. With this configuration, the controller 30 can satisfy the operator's degenerate operation request such as "Since an abnormality has occurred in the swing hydraulic motor 2A but no abnormality has occurred in the traveling hydraulic motor 2M, I would like to operate the traveling hydraulic motor 2M while prohibiting the movement of the swing hydraulic motor 2A." The controller 30 may be configured to accept such a degenerate operation request only when a specific switch provided in the cabin 10 or the like is operated by the operator. The specific switch is, for example, a push button switch for switching the operation mode of the excavator 100 between the normal mode and the degenerate operation mode. The normal mode is, for example, an operation mode that is not the degenerate operation mode, and is an operation mode in which the operation of all actuators is prohibited when an abnormality is detected in the operation of one actuator.

In addition, if the failure determination unit 30A determines that there is an abnormality in the slewing operation lever when the slewing operation lever is operated to the left, it may stop the supply of current to the solenoid valve 31DL through the slewing current output unit without stopping the supply of current to the solenoid valve 31DR through the slewing current output unit, thereby prohibiting only the movement of the slewing hydraulic motor 2A for left turning without prohibiting the movement of the slewing hydraulic motor 2A for right turning.

In addition, when the failure determination unit 30A determines that there is an abnormality in the boom operation lever (right operation lever 26R), it may prohibit the movement of the boom cylinder 7 by stopping the supply of current to the solenoid valve 31BL and the solenoid valve 31BR through the boom current output unit, and may prohibit the movement of the bucket cylinder 9 by stopping the supply of current to the solenoid valve 31CL and the solenoid valve 31CR through the bucket current output unit. This is because the bucket operation lever, together with the boom operation lever, constitutes the right operation lever 26R. In this case, the failure determination unit 30A does not need to prohibit the movement of the arm cylinder 8 and the swing hydraulic motor 2A in response to the operation of the arm operation lever and the swing operation lever that constitute the left operation lever 26L. In addition, the failure determination unit 30A does not need to prohibit the movement of the traveling hydraulic motor 2M in response to the operation of the traveling operation device.

However, if the failure determination unit 30A determines that there is an abnormality in one specific control lever, such as when it determines that there is an abnormality in the swing control lever, it may temporarily prohibit the movement of all actuators. In other words, the failure determination unit 30A may stop the movement of all actuators that are in operation by outputting an OFF level enable command signal to each of the enable units 30E corresponding to each actuator. Then, after temporarily stopping the movement of all actuators, the failure determination unit 30A may release the prohibition on the movement of actuators other than the actuator corresponding to the specific control lever determined to be abnormal.

As described above, as shown in FIG. 1, the excavator 100 according to the embodiment of the present disclosure includes a lower traveling body 1, an upper rotating body 3 rotatably mounted on the lower traveling body 1, a plurality of actuators (a swing hydraulic motor 2A, a traveling hydraulic motor 2M, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9), a plurality of electric operation devices (operation devices 26) used to operate the plurality of actuators, and a control device (controller 30) capable of determining whether or not one of the plurality of operation devices 26 has an abnormality. The controller 30 is configured to prohibit the movement of one actuator in response to the operation of one operation device 26 determined to have an abnormality.

With this configuration, the shovel 100 can individually determine whether or not there is an abnormality in the multiple operating devices 26, and then individually prohibit the movement of the multiple actuators. This has the effect of realizing a state in which the movement of the actuator not related to the abnormality is permitted even when the movement of the actuator related to the abnormality is not permitted. In addition, the shovel 100 has the effect of preventing the movement of the actuator related to the abnormality from being continuously permitted. Therefore, the shovel 100 can prevent the occurrence of malfunctions such as a large movement of the corresponding actuator despite the operator only slightly operating a specific operating device 26, or a movement of the corresponding actuator despite the operator not operating a specific operating device 26.

The controller 30 may also be configured to allow the movement of other actuators in response to the operation of other operating devices 26 that are determined to be normal.

With this configuration, the excavator 100 actively tolerates actuator movements that are not related to the abnormality, which has the effect of more reliably realizing a state in which actuator movements that are not related to the abnormality are tolerated even when actuator movements that are not related to the abnormality are not tolerated.

The controller 30 may also determine whether or not there is an abnormality in the operating device 26 based on the output of a first sensor (operation sensor 29) that detects the operation content of the operating device 26, the output of a second sensor (at least one of a pressure sensor 32, a posture sensor, a cylinder pressure sensor, a motor pressure sensor, and a stroke sensor, etc.) that directly or indirectly detects the actual movement of the actuator, and the output of a third sensor (solenoid valve 31 that functions as a current sensor) that detects the value of the current that causes the actuator to move. The current that causes the actuator to move is, for example, a current supplied to the solenoid valve 31 that generates a pilot pressure that operates the control valve 175 that controls the flow rate of hydraulic oil that causes the boom cylinder 7 to expand and contract. In addition, when the actuator is an electromagnetic actuator, the current that causes the actuator to move may be a current that is supplied directly to the actuator.

With this configuration, the excavator 100 has the advantage of being able to prohibit the movement of the actuator related to the abnormality simply by determining whether there is an abnormality in the movement of the actuator in response to the operation of the operating device 26, without having to specify whether the abnormality is occurring in the operating device 26, the actuator, the first sensor, the second sensor, or the third sensor, etc. This is because the controller 30 can compare the outputs of multiple sensors, such as the first sensor, the second sensor, and the third sensor, with each other to determine whether there is an abnormality.

The controller 30 may also be configured to generate a PWM signal to control the current that causes the actuator to move, and when it is determined that one of the operating devices 26 is abnormal, to change the waveform of the generated PWM signal to prohibit the actuator from moving in response to the operation of the operating device 26. In the example shown in FIG. 7, when the controller 30 determines that one of the operating devices 26 is abnormal, it sets the duty ratio of the PWM signal (input) generated in response to a control signal from the control unit 30B to 0%, thereby prohibiting the actuator from moving in response to the operation of the operating device 26.

With this configuration, the excavator 100 has the advantage of being able to prohibit the movement of actuators related to an abnormality by controlling the current supplied to hydraulic control devices such as the solenoid valve 31, which are continuously used even when no abnormality is detected, without the need for additional hydraulic control devices such as emergency stop valves that operate only when an abnormality is detected.

In addition, when the controller 30 determines that one operating device 26 is abnormal, it may stop the movement of all of the actuators, and then release the prohibition on the movement of the other actuators in response to the operation of other electric operating devices that are not determined to be abnormal.

This configuration allows the excavator 100 to satisfy the operator's degenerate operation requirements.

The above describes preferred embodiments of the present invention in detail. However, the present invention is not limited to the above-described embodiments, nor to the embodiments described below. Various modifications or substitutions can be applied to the above-described or below-described embodiments without departing from the scope of the present invention. Furthermore, features described separately can be combined as long as no technical contradiction occurs.

For example, in the above embodiment, the controller 30 is provided in the cabin 10 and is configured to be able to determine whether or not there is an abnormality in the operating device 26 provided in the cabin 10. However, the controller 30 may be provided outside the shovel 100. In this case, the controller 30 may be provided in a remote control room outside the shovel 100 and configured to be able to determine whether or not there is an abnormality in the electric operating device 26 also provided in the remote control room. In this case, the electric operating device 26, the controller 30, and the shovel 100 constitute a control system for the shovel.

In the above embodiment, the enable unit 30E is a part of the controller 30, and is disposed downstream of the control unit 30B between the control unit 30B and the current output unit 30F in the flow of information. Therefore, the enable unit 30E can handle the control signal generated by the control unit 30B, and has the effect of more reliably cutting off the current supplied to the solenoid valve 31 compared to when it is disposed upstream of the control unit 30B. This is because, if it is disposed upstream of the control unit 30B, it may not be possible to suppress the supply of an inappropriate current to the solenoid valve 31 due to an abnormality in the control unit 30B. In addition, the enable unit 30E has the effect of being able to handle a low voltage signal, rather than a relatively large current output by the current output unit 30F, and has the effect of being able to adopt a simpler circuit configuration compared to when a relatively large current is handled. However, the enable unit 30E may be disposed upstream of the control unit 30B, for example, between the input unit 30C and the control unit 30B. The enable unit 30E may also be a part of a control device other than the controller 30 that is outside the controller 30. In this case, the enable unit 30E may be disposed between the controller 30 (current output unit 30F) and the solenoid valve 31.

1: Lower traveling body 2: Swing mechanism 2A: Swing hydraulic motor 2M: Travel hydraulic motor 2ML: Left traveling hydraulic motor 2MR: Right traveling 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: Regulator 14: Main pump 14L: Left main pump 14R: Right main pump 15: Pilot pump 17: Control valve unit 18L: Left throttle 18R: Right throttle 19L: Left control pressure sensor 19R: Right control pressure sensor 26: Operation device 26D: Travel lever 26DL: Left travel lever 26DR: Right travel lever 26L: Left operation lever 26R: Right operation lever 28: Discharge pressure sensor 29, 29DL, 29DR, 29LA, 29LB, 29RA, 29RB, ... operation sensor 30 ... controller 30A ... failure determination section 30B ... control section 30C ... input section 30D ... conversion section 30E ... enable section 30E1 ... PWM output circuit 30E2 ... interlock circuit 30E3 ... AND circuit 30F ... current output section 31, 31AL to 31FL, 31AR to 31FR ... solenoid valve 32, 32AL to 32FL, 32AR to 32FR ... pressure sensor 35 ... gate lock valve 50 ... gate lock lever 70 ... space recognition device 70B ... rear sensor 70F ... front sensor 70L ... left sensor 70R ... right sensor 100 ... shovel 171 to 176 ... control valve AT ... attachment S5: Turning angular velocity sensor S7B: Boom bottom pressure sensor S7R: Boom rod pressure sensor S8B: Arm bottom pressure sensor S8R: Arm rod pressure sensor S9B: Bucket bottom pressure sensor S9R: Bucket rod pressure sensor SW, SW1, SW2: Switch

Claims (5)

A lower running body;
An upper rotating body rotatably mounted on the lower traveling body;
A plurality of actuators;
A plurality of electric operating devices used to operate the plurality of actuators;
A control device that determines whether or not one of the plurality of electric operating devices has an abnormality,
The control device prohibits a movement of one of the actuators in response to an operation of one of the electric operation devices determined to have an abnormality.
Shovel. The control device allows the movement of the other actuator in response to the operation of the other electric operation device determined to be normal.
The shovel according to claim 1. The control device determines whether or not there is an abnormality in one of the plurality of electric operating devices based on an output of a first sensor that detects the operation content of the electric operating device, an output of a second sensor that detects the movement of the actuator, and an output of a third sensor that detects the value of a current that causes the movement of the actuator.
The shovel according to claim 1. The control device controls a current that brings about movement of the actuator by generating a PWM signal, and when it is determined that one of the plurality of electric operating devices has an abnormality, it inhibits movement of one of the actuators in response to operation of the one electric operating device determined to have an abnormality by changing the waveform of the generated PWM signal.
The shovel according to claim 1. When the control device determines that one of the plurality of electric operation devices has an abnormality, the control device prohibits the movements of all of the plurality of actuators, and then releases the prohibition on the movements of the other actuators in response to the operation of the other electric operation devices that have not been determined to have an abnormality.
The shovel according to claim 1.