JP2022151543A - Shovel - Google Patents

Abstract

To facilitate determination of an erroneous operation.SOLUTION: A shovel comprises a detection unit that detects a physical quantity that varies according to the content of an operation on an operating device that operates an actuator, and a determination unit that determines whether the operation is an erroneous operation according to whether the physical quantity has continuously increased or decreased.SELECTED DRAWING: Figure 1

Description

The present invention relates to excavators.

In conventional work vehicles, there is known a technique of locking the operation of the hydraulic actuator by the operating member when the operation by the operating member is determined to be an erroneous operation. For example, conventionally, when the elapsed time from the release state allowing the supply of pilot pressure to the actuator control valve is less than a predetermined time and the pilot pressure becomes equal to or higher than a predetermined pressure, the operating member is operated. is determined as an erroneous operation and the operation of the hydraulic actuator is locked (Patent Document 1).

Japanese Patent No. 5467176

In the conventional technique described above, it is necessary to set a threshold for the elapsed time from the release state allowing the supply of the pilot pressure and a threshold for the pilot pressure. However, the manner in which the pilot pressure rises is affected by the viscosity of the hydraulic oil, and the viscosity of the hydraulic oil is also affected by the temperature of the outside air and the like. Therefore, conventionally, these thresholds must be appropriately set according to the environment in which the work vehicle is used, making it difficult to easily determine an erroneous operation. Furthermore, a low pilot pressure threshold and a long elapsed time threshold are required to fully lock the lever erroneous operation. However, if this is done, the user's intended operation will be locked, making the machine less user-friendly. Therefore, these thresholds must be set appropriately, making it difficult to easily determine an erroneous operation.

Therefore, in view of the above circumstances, it is an object of the present invention to facilitate determination of an erroneous operation.

An excavator according to an embodiment of the present invention includes a detection unit that detects a physical quantity that changes according to the details of an operation performed on an operation device that operates an actuator, and a determination unit that determines whether the operation is an erroneous operation.

To facilitate determination of erroneous operation.

1 is a side view of a shovel according to an embodiment of the present invention; FIG. 1 is a top view of a shovel according to an embodiment of the present invention; FIG. It is a figure which shows the structural example of the basic system mounted in an excavator. It is a figure which shows the structural example of the hydraulic system mounted in an excavator. It is a figure which shows an example of the electric circuit diagram which shows the relationship between a control valve and a controller. 4 is a first flow chart for explaining the operation of the shovel of the embodiment; FIG. 4 is a diagram for explaining the relationship between a negative control pressure, an operation signal, and a control signal; It is a second flow chart explaining the operation of the shovel of the embodiment. It is a figure explaining the relationship between a pilot pressure, an operation signal, and a control signal. FIG. 3 is a diagram showing another configuration example of a hydraulic system mounted on an excavator; It is a figure explaining the relationship between the discharge pressure of a reserve pump, an operation signal, and a control signal.

(embodiment)
First, a shovel 100 as an excavator according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a side view of the shovel 100, and FIG. 2 is a top view of the shovel 100. FIG.

In this embodiment, the undercarriage 1 of the excavator 100 includes a crawler 1C as a driven body. The crawler 1</b>C is driven by a traveling hydraulic motor 2</b>M mounted on the lower traveling body 1 . However, the travel hydraulic motor 2M may be a travel motor generator as an electric actuator. 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. Since the lower traveling body 1 is driven by the crawler 1C, it functions as a driven body.

An upper rotating body 3 is rotatably mounted on the lower traveling body 1 via a rotating mechanism 2 . The turning mechanism 2 as a driven body is driven by a turning hydraulic motor 2A mounted on the upper turning body 3 . However, the turning hydraulic motor 2A may be a turning motor-generator as an electric actuator. Since the upper rotating body 3 is driven by the rotating mechanism 2, it functions as a driven body.

A boom 4 as a driven body is attached to the upper revolving body 3 . An arm 5 as a driven body is attached to the tip of the boom 4 , and a bucket 6 as a driven body and an end attachment is attached to the tip of the arm 5 . The boom 4, arm 5 and bucket 6 constitute an excavation attachment which is an example of an attachment. A boom 4 is driven by a boom cylinder 7 , an arm 5 is driven by an arm cylinder 8 , and a bucket 6 is driven by a bucket cylinder 9 .

A boom angle sensor S1 is attached to the boom 4, an arm angle sensor S2 is attached to the arm 5, and a bucket angle sensor S3 is attached to the bucket 6.

A boom angle sensor S1 detects the rotation angle of the boom 4 . In this embodiment, the boom angle sensor S1 is an acceleration sensor, and can detect the boom angle, which is the rotation angle of the boom 4 with respect to the upper rotating body 3 . The boom angle is, for example, the minimum angle when the boom 4 is lowered, and increases as the boom 4 is raised.

Arm angle sensor S2 detects the rotation angle of arm 5 . In this embodiment, the arm angle sensor S2 is an acceleration sensor, and can detect the arm angle, which is the rotation angle of the arm 5 with respect to the boom 4 . The arm angle is, for example, the minimum angle when the arm 5 is closed most, and increases as the arm 5 is opened.

A bucket angle sensor S3 detects the rotation angle of the bucket 6 . In this embodiment, the bucket angle sensor S3 is an acceleration sensor and can detect the bucket angle, which is the rotation angle of the bucket 6 with respect to the arm 5 . The bucket angle is, for example, the smallest angle when the bucket 6 is closed most, and increases as the bucket 6 opens.

The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 are each a potentiometer using a variable resistor, a stroke sensor that detects the stroke amount of the corresponding hydraulic cylinder, and a rotary encoder that detects the rotation angle around the connecting pin. , a gyro sensor, a combination of an acceleration sensor and a gyro sensor, or the like.

The upper revolving body 3 is provided with a cabin 10 as an operator's cab, and an engine 11 and the like as a prime mover of the shovel 100 are mounted. The upper rotating body 3 is also provided with a controller 30, an object detection device 70, an imaging device 80, an orientation detection device 85, a body tilt sensor S4, a turning angular velocity sensor S5, and the like. An operating device 26 and the like are provided inside the cabin 10 . In this document, for the sake of convenience, the side of the upper rotating body 3 to which the boom 4 is attached is referred to as the front, and the side to which the counterweight is attached is referred to as the rear.

Further, in this embodiment, an electric motor may be used as the prime mover instead of using the engine 11 . In this case, a power storage device is also mounted to supply electric power to the electric motor. A power storage device is a device for storing electric power, and is, for example, an electric double layer capacitor, a lithium ion battery, a nickel metal hydride battery, or the like. By controlling the electric motor using the inverter, the main pump 14 is rotationally driven by electric power stored in the power storage device.

Controller 30 is a control device for controlling excavator 100 . In this embodiment, the controller 30 is configured by a computer including a CPU, RAM, NVRAM, ROM, and the like. Then, the controller 30 reads a program corresponding to each functional element from the ROM, loads it into the RAM, and causes the CPU to execute the corresponding process.

The object detection device 70 is configured to detect objects existing around the excavator 100 . Further, the object detection device 70 may be configured to calculate the distance from the object detection device 70 or the excavator 100 to the recognized object. Objects include, for example, people, animals, vehicles, construction equipment, buildings, holes, and the like. The object detection device 70 includes, for example, an ultrasonic sensor, millimeter wave radar, stereo camera, LIDAR, distance image sensor, infrared sensor, and the like. In this embodiment, the object detection device 70 includes a front 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 revolving structure 3, and a left end of the upper surface of the upper revolving structure 3. and a right sensor 70R attached to the right end of the upper surface of the upper swing body 3 .

The object detection device 70 may be configured to detect a predetermined object within a predetermined area set around the excavator 100 . For example, it may be configured to be able to distinguish between a person and an object other than a person.

The imaging device 80 is configured to image the surroundings of the excavator 100 . In this embodiment, the imaging device 80 includes a rearward camera 80B attached to the rear end of the upper surface of the upper rotating body 3, a left camera 80L attached to the left end of the upper surface of the upper rotating body 3, and an upper surface of the upper rotating body 3. It includes a right camera 80R mounted on the right end. It may also include a front camera.

The rear camera 80B is positioned adjacent to the rear sensor 70B, the left camera 80L is positioned adjacent to the left sensor 70L, and the right camera 80R is positioned adjacent to the right sensor 70R. A forward camera may be positioned adjacent to the forward sensor 70F.

The image captured by the imaging device 80 is displayed on the display device DS installed in the cabin 10 . The imaging device 80 may be configured to display a viewpoint-converted image such as a bird's-eye view image on the display device DS. The bird's-eye view image is generated, for example, by synthesizing images output from the rear camera 80B, the left camera 80L, and the right camera 80R.

The imaging device 80 may function as an object detection device. In this case, the object detection device 70 may be omitted.

With this configuration, the excavator 100 can display an image of the object detected by the object detection device 70 on the display device DS. Therefore, when the movement of the driven body is restricted or prohibited, the operator of the excavator 100 can immediately confirm what the object is by looking at the image displayed on the display device DS. can.

The orientation detection device 85 is configured to detect information on the relative relationship between the orientation of the upper rotating body 3 and the orientation of the lower traveling body 1 (hereinafter referred to as "orientation information"). For example, the direction detection device 85 may be composed of a combination of a geomagnetic sensor attached to the lower traveling body 1 and a geomagnetic sensor attached to the upper rotating body 3 .

Alternatively, the orientation detection device 85 may be configured by a combination of a GNSS receiver attached to the lower traveling body 1 and a GNSS receiver attached to the upper swing body 3 . In a configuration in which the upper rotating body 3 is driven to rotate by a rotating motor-generator, the orientation detection device 85 may be configured by a resolver. The orientation detection device 85 may be arranged, for example, at a center joint provided in relation to the revolving mechanism 2 that achieves relative rotation between the lower traveling body 1 and the upper revolving body 3 .

The body tilt sensor S4 detects the tilt of the excavator 100 with respect to a predetermined plane. In this embodiment, the machine body tilt sensor S4 is an acceleration sensor that detects the tilt angle of the longitudinal axis and the tilt angle of the lateral axis of the upper rotating body 3 with respect to the horizontal plane. It may be composed of a combination of an acceleration sensor and a gyro sensor. For example, the longitudinal axis and the lateral axis of the upper swing body 3 are orthogonal to each other and pass through a shovel center point, which is one point on the swing axis of the shovel 100 .

The turning angular velocity sensor S5 detects the turning angular velocity of the upper turning body 3 . In this embodiment, it is a gyro sensor. It may be a resolver, a rotary encoder, or the like. The turning angular velocity sensor S5 may detect turning velocity. The turning speed may be calculated from the turning angular velocity.

In the following, any combination of boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, fuselage tilt sensor S4 and turning angular velocity sensor S5 are also collectively referred to as attitude sensors.

Next, a basic system mounted on the excavator 100 will be described with reference to FIG. FIG. 3 shows a configuration example of a basic system mounted on the excavator 100. As shown in FIG. In FIG. 3, the mechanical power transmission line is indicated by a double line, the hydraulic oil line is indicated by a thick solid line, the pilot line is indicated by a broken line, and the electric power line is indicated by a thin solid line.

The basic system mainly includes an engine 11, a main pump 14, a pilot pump 15, a control valve 17, an operation device 26, an operation pressure sensor 29, a controller 30, an alarm device 49, a control valve 60, an object detection device 70, and an engine control unit. (ECU 74), engine speed adjustment dial 75, imaging device 80, and the like.

The engine 11 is a diesel engine that employs isochronous control that maintains a constant engine speed regardless of increases or decreases in load. The fuel injection amount, fuel injection timing, boost pressure, etc. in the engine 11 are controlled by the ECU 74 . The engine 11 is connected to a main pump 14 and a pilot pump 15 as hydraulic pumps. The main pump 14 is connected to a control valve 17 via a hydraulic oil line.

The control valve 17 is a hydraulic control device that controls the hydraulic system of the excavator 100 . The control valve 17 is connected to hydraulic actuators such as a left travel hydraulic motor 2ML, a right travel hydraulic motor 2MR, a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, and a turning hydraulic motor.

Specifically, control valve 17 includes a plurality of spool valves corresponding to each hydraulic actuator. Each spool valve is configured to be displaceable according to the pilot pressure so that the opening area of the PC port and the opening area of the CT port can be increased or decreased. The PC port is a port that communicates between the main pump 14 and the hydraulic actuator. A CT port is a port that communicates between a hydraulic actuator and a hydraulic fluid tank.

The operating device 26 is a device used by an operator to operate the actuator. The actuator includes at least one of a hydraulic actuator and an electric actuator. In this embodiment, the operating device 26 is a hydraulic operating device, and supplies the hydraulic oil discharged by the pilot pump 15 to the corresponding pilot port of the spool valve in the control valve 17 via a pilot line.

The pressure (pilot pressure) of hydraulic fluid supplied to each of the pilot ports is a pressure corresponding to the operation direction and amount of operation of the operating device 26 corresponding to each of the hydraulic actuators. The operating device 26 includes, for example, a left operating lever, a right operating lever, and a travel operating device.

A discharge pressure sensor 28 detects 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 operating pressure sensor 29 detects details of the operation of the operating device 26 by the operator. In this embodiment, the operation pressure sensor 29 detects the operation direction and the operation amount of the operation device 26 corresponding to each actuator in the form of pressure (operation pressure), and outputs the detected value to the controller 30 . The operation content of the operation device 26 may be detected using a sensor other than the operation pressure sensor.

The alarm device 49 is configured to call attention of a person involved in the work of the excavator 100 . The alarm device 49 may be configured by, for example, a combination of an indoor alarm device and an outdoor alarm device.

The indoor alarm device is configured to alert the operator of the excavator 100 in the cabin 10 . The indoor alarm device includes, for example, at least one of an audio output device, a vibration generator, and a light emitting device provided inside the cabin 10 . The room alarm device may be a display device DS.

The outdoor alarm device is configured to call the attention of workers working around the excavator 100 . The outdoor alarm device includes, for example, at least one of an audio output device and a light emitting device provided outside the cabin 10 . The audio output device as the outdoor alarm device may be, for example, a travel alarm device attached to the bottom surface of the upper swing body 3 . The outdoor alarm device may be a light-emitting device provided on the upper swing body 3 . However, the outdoor alarm device may be omitted. For example, when the object detection device 70 detects an object, the alarm device 49 may notify a person involved in the work of the shovel 100 to that effect.

The control valve 60 is configured to switch between a valid state and an invalid state of the operating device 26 . The valid state of the operating device 26 is a state in which the operator can operate the hydraulic actuators using the operating device 26 . The disabled state of the operating device 26 is a state in which the operator cannot operate the hydraulic actuators using the operating device 26 .

In this embodiment, control valve 60 includes a gate lock valve configured to operate in response to commands from controller 30 . Specifically, the control valve 60 is arranged in a pilot line that connects the pilot pump 15 and the operating device 26 and is configured to switch between disconnection and communication of the pilot line according to a command from the controller 30 .

The operation device 26 becomes active when the gate lock valve is opened by, for example, operating a gate lock lever (not shown). When the gate lock valve is opened means that the pilot line is in communication with the gate lock valve. In the following description, the state in which the gate lock valve is opened may be expressed as the communicating state.

Further, the operating device 26 is disabled when the gate lock valve is closed by operating the gate lock lever. When the gate lock valve is closed means that the pilot line is blocked by the gate lock valve. In the following description, the state in which the gate lock valve is opened may be expressed as the blocked state.

The ECU 74 outputs data regarding the state of the engine 11 , such as coolant temperature, to the controller 30 . The regulator 13 of the main pump 14 outputs data regarding the tilt angle of the swash plate to the controller 30 . The discharge pressure sensor 28 outputs data regarding the discharge pressure of the main pump 14 to the controller 30 . An oil temperature sensor 14c provided in a pipe line between the hydraulic oil tank and the main pump 14 outputs data regarding the temperature of the hydraulic oil flowing through the pipe line to the controller 30. The operating pressure sensor 29 outputs data regarding the pilot pressure generated when the operating device 26 is operated to the controller 30 . The controller 30 can accumulate these data in a temporary storage unit (memory) and output them to the display device DS when necessary.

The engine speed adjustment dial 75 is a dial for adjusting the speed of the engine 11 . The engine speed adjustment dial 75 outputs data regarding the set state of the engine speed to the controller 30 . The engine speed adjustment dial 75 is configured to switch the engine speed in four stages of SP mode, H mode, A mode and idling mode.

The SP mode is a rotation speed mode that is selected when it is desired to give priority to the amount of work, and utilizes the highest engine speed. The H mode is a rotational speed mode that is selected when it is desired to achieve both work load and fuel efficiency, and utilizes the second highest engine rotational speed. The A mode is a rotational speed mode selected when it is desired to operate the excavator 100 with low noise while giving priority to fuel efficiency, and uses the third highest engine rotational speed. The idling mode is a rotational speed mode that is selected when the engine 11 is to be in an idling state, and uses the lowest engine rotational speed. The engine 11 is controlled so that the engine speed corresponding to the speed mode set by the engine speed adjustment dial 75 is constant. The rotation speed mode is not limited to the present embodiment, and may be set in five or more stages.

The display device DS has a control section DSa, an image display section DS1, and a switch panel DS2 as an input section. The control section DSa is configured to be able to control the image displayed on the image display section DS1. In this embodiment, the controller DSa is configured by a computer including a CPU, RAM, NVRAM, ROM, and the like. In this case, the control unit DSa reads a program corresponding to each functional element from the ROM, loads it into the RAM, and causes the CPU to execute the corresponding process. However, each functional element may be configured by hardware, or may be configured by a combination of software and hardware. Also, the image displayed on the image display section DS1 may be controlled by the controller 30 or the imaging device 80 .

The switch panel DS2 is a panel containing hardware switches. The switch panel DS2 may be a touch panel. The display device DS operates by being supplied with power from the storage battery BT. The storage battery BT is charged with electricity generated by the alternator 11a, for example. The power of storage battery BT may be supplied to controller 30 and the like. A starter 11 b of the engine 11 is driven by, for example, electric power from the storage battery BT to start the engine 11 .

The lever button LB is a button provided on the operating device 26 . In this embodiment, the lever button LB is a button provided at the tip of the operating lever as the operating device 26 . An operator of the excavator 100 can operate the lever button LB while operating the operating lever. For example, the operator can press the lever button LB with the thumb while gripping the operating lever with the hand.

Next, functions of the controller 30 of this embodiment will be described. The controller 30 of the present embodiment realizes the functions of each section described later by executing a program stored in a ROM or the like by the CPU.

The controller 30 of this embodiment has a switching section 31 , a detection section 32 and a determination section 33 . The switching unit 31 outputs a control signal for controlling the state of the control valve 60 (gate lock valve) according to the switching instruction from the determination unit 33 . Specifically, the switching unit 31 receives a control valve switching instruction from the determination unit 33 and switches the control valve 60 from the communicating state to the blocking state.

Further, the switching unit 31 may switch the control valve 60 from the closed state to the open state or from the open state to the closed state in accordance with the operation of a gate lock lever (not shown).

The detection unit 32 detects physical quantities detected by the excavator 100 . Specifically, the physical quantity in the present embodiment is, for example, the pressure of the hydraulic oil (pilot pressure) detected by the operating pressure sensor 29, the control pressure (negative control pressure) detected by the control pressure sensor 19, which will be described later, and the like. including. In other words, the physical quantity in the present embodiment is a value that changes according to the amount of lever operation (details of operation) on the operating device 26 of the excavator 100, and is a value that is detected according to the content of the operation on the operating device 26. be.

When the control valve 60 is in the open state, the determination unit 33 determines whether the physical quantity detected by the detection unit 32 continuously decreases or increases multiple times within a predetermined time period after the switch 51 is switched to the ON state, Also, it is determined whether or not the operation of the operating device 26 is an erroneous operation depending on whether the value is equal to or less than a predetermined value or equal to or greater than a predetermined value.

In the present embodiment, the determination unit 33 determines that the physical quantity is the control pressure (negative control pressure) detected by the control pressure sensor 19, and the negative control pressure is detected multiple times in succession within a predetermined time after the switch 51 is switched to the ON state. Decrease and determine whether or not the negative control pressure is equal to or less than a predetermined value. Here, the predetermined time and the predetermined value after switching to the ON state of the switch 51 are values that are set in advance, and are defined values that are set independently of the environment of the work site of the excavator 100. be.

Then, when the negative control pressure decreases continuously a plurality of times within a predetermined period of time after the switch 51 is switched to the ON state, the determination unit 33 determines that the operation of the operating device 26 at this time is an erroneous operation. 31 of an instruction to switch the gate lock valve from the communication state to the cutoff state.

Note that the determination unit 33 of the present embodiment may determine, for example, whether the control valve 60 is in the communicating state or in the blocking state.

Next, a configuration example of the hydraulic system mounted on the excavator 100 will be described with reference to FIG. 4 . FIG. 4 is a diagram showing a configuration example of a hydraulic system mounted on the excavator 100. As shown in FIG. FIG. 4 shows the mechanical driveline, hydraulic lines, pilot lines and electrical control system in double, solid, dashed 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 17, an operation device 26, a discharge pressure sensor 28, an operation pressure sensor 29, a controller 30, a control valve 60, and the like. include.

In FIG. 4, the hydraulic system circulates hydraulic oil from a main pump 14 driven by an engine 11 to a hydraulic oil tank through a center bypass line 40 or a parallel line 42 .

The engine 11 is a drive source for the excavator 100 . In this embodiment, the engine 11 is, for example, a diesel engine that operates to maintain a predetermined number of revolutions. An output shaft of the engine 11 is connected to respective input shafts of the main pump 14 and the pilot pump 15 .

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

The regulator 13 controls the discharge amount of the main pump 14 . In this embodiment, the regulator 13 controls the discharge amount of the main pump 14 by adjusting the tilt angle of the swash plate of the main pump 14 according to the control command from the controller 30 .

The pilot pump 15 supplies hydraulic fluid to hydraulic control equipment including the operating device 26 via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump.

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

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

The left center bypass line 40L is a hydraulic fluid line passing through control valves 171, 173, 175L and 176L arranged within the control valve 17. As shown in FIG. The right center bypass line 40R is a hydraulic fluid line passing through control valves 172, 174, 175R and 176R arranged within the control valve 17. As shown in FIG.

The control valve 171 supplies the hydraulic fluid discharged by the left main pump 14L to the left traveling hydraulic motor 2ML and discharges the hydraulic fluid discharged by the left traveling hydraulic motor 2ML to the hydraulic fluid tank. It is a spool valve that switches the flow.

The control valve 172 supplies the hydraulic fluid discharged by the right main pump 14R to the right traveling hydraulic motor 2MR and discharges the hydraulic fluid discharged by the right traveling hydraulic motor 2MR to the hydraulic fluid tank. It is a spool valve that switches the flow.

The control valve 173 supplies hydraulic fluid discharged by the left main pump 14L to the turning hydraulic motor 2A, and controls the flow of hydraulic fluid in order to discharge the hydraulic fluid discharged by the turning hydraulic motor 2A to the hydraulic fluid tank. It is a switching spool valve.

The control valve 174 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 bucket cylinder 9 and 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 fluid to supply the hydraulic fluid 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 from 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 switches the flow of hydraulic fluid to supply the hydraulic fluid discharged by the left main pump 14L to the arm cylinder 8 and to discharge the hydraulic fluid in the arm cylinder 8 to the hydraulic fluid tank. .

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

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

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

The operating device 26 includes a left operating lever 26L, a right operating lever 26R and a travel lever 26D. 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 and operating the arm 5. As shown in FIG. When the left operating lever 26L is operated in the front-rear direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure corresponding to the amount of lever operation to the pilot port of the control valve 176 . Further, when operated in the left-right direction, hydraulic oil discharged from the pilot pump 15 is used to introduce a control pressure corresponding to the amount of lever operation to 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 fluid into the right pilot port of the control valve 176L and introduces hydraulic fluid into the left pilot port of the control valve 176R. . Further, when the left operating lever 26L is operated in the arm opening direction, it introduces hydraulic fluid into the left pilot port of the control valve 176L and introduces hydraulic fluid into the right pilot port of the control valve 176R. When the left control lever 26L is operated in the left turning direction, hydraulic oil is introduced into the left pilot port of the control valve 173, and when it is operated in the right turning direction, the right pilot port of the control valve 173 is introduced. Hydraulic oil is introduced into

The right operating lever 26R is used for operating the boom 4 and operating the bucket 6 . When the right operating lever 26R is operated in the longitudinal direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure corresponding to the amount of lever operation to the pilot port of the control valve 175 . Further, when operated in the left-right direction, hydraulic oil discharged from the pilot pump 15 is used to introduce a control pressure corresponding to the amount of lever operation to the pilot port of the control valve 174 .

Specifically, when the right operation lever 26R is operated in the boom lowering direction, hydraulic fluid is introduced into the left pilot port of the control valve 175R. Further, when the right operation lever 26R is operated in the boom raising direction, it introduces hydraulic fluid into the right pilot port of the control valve 175L and introduces hydraulic fluid into the left pilot port of the control valve 175R. When the right operation lever 26R is operated in the bucket closing direction, hydraulic oil is introduced into the right pilot port of the control valve 174, and when it is operated in the bucket opening direction, the hydraulic oil is introduced into the left pilot port of the control valve 174. Introduce hydraulic oil.

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. It may be configured to be interlocked with the left travel pedal. When the left travel lever 26DL is operated in the longitudinal direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure corresponding to the amount of lever operation to the pilot port of the control valve 171 . The right travel lever 26DR is used to operate the right crawler 1CR. It may be configured to interlock with the right travel pedal. When the right travel lever 26DR is operated in the longitudinal direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure corresponding to the amount of lever operation to 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 applies to the discharge pressure sensor 28R.

The operation pressure sensor 29 includes operation pressure sensors 29LA, 29LB, 29RA, 29RB, 29DL and 29DR. The operation pressure sensor 29LA detects the content of the operator's operation of the left operation lever 26L in the front-rear direction in the form of pressure, and outputs the detected value to the controller 30. FIG. The operation content is, for example, the lever operation direction, lever operation amount (lever operation angle), and the like.

Similarly, the operation pressure sensor 29LB detects, in the form of pressure, the details of the left-right direction operation of the left operation lever 26L by the operator, and outputs the detected value to the controller 30 . The operation pressure sensor 29RA detects the content of the operator's operation of the right operation lever 26R in the front-rear direction in the form of pressure, and outputs the detected value to the controller 30. FIG.

The operation pressure sensor 29 RB detects, in the form of pressure, the details of the operator's operation of the right operation lever 26 R in the horizontal direction, and outputs the detected value to the controller 30 . The operation pressure sensor 29DL detects, in the form of pressure, the content of the operator's operation of the left traveling lever 26DL in the front-rear direction, and outputs the detected value to the controller 30 . The operation pressure sensor 29DR detects, in the form of pressure, the content of the operator's operation of the right travel lever 26DR in the front-rear direction, and outputs the detected value to the controller 30 .

The controller 30 receives the output of the operating pressure sensor 29 and outputs a control command to the regulator 13 as necessary to change the discharge amount of the main pump 14 .

Here, negative control using the throttle 18 and the control pressure sensor 19 will be described. The throttle 18 includes a left throttle 18L and a right throttle 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

A left throttle 18L is disposed between the most downstream control valve 176L and the hydraulic oil tank in the left center bypass line 40L. Therefore, the flow of hydraulic oil discharged from the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L generates a control pressure (negative 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. FIG.

The value detected by the control pressure sensor 19 is a negative control pressure that changes when the hydraulic fluid discharged from the main pump 14 flows into the hydraulic actuator due to the movement of the control valves 171 to 176 corresponding to the lever operation amount of the operating device 26. be.

The controller 30 controls the discharge amount of the left main pump 14L by adjusting the tilt angle of the swash plate of the left main pump 14L according to this control pressure. The controller 30 decreases the discharge amount of the left main pump 14L as the control pressure increases, and increases the discharge amount of the left main pump 14L as the control pressure decreases. The discharge amount of the right main pump 14R is similarly controlled.

Specifically, in the standby state in which none of the hydraulic actuators in the excavator 100 is operated as shown in FIG. It reaches the diaphragm 18L. The flow of hydraulic fluid discharged from 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 minimum allowable discharge amount, thereby suppressing pressure loss (pumping loss) when the discharged hydraulic oil passes through the left center bypass pipe 40L. On the other hand, when one of the hydraulic actuators is operated, hydraulic fluid discharged from the left main pump 14L flows into the operated hydraulic actuator via the control valve corresponding to the operated hydraulic actuator.

Then, the flow of hydraulic oil discharged from the left main pump 14L reduces or eliminates the amount reaching the left throttle 18L, thereby reducing the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 increases the discharge amount of the left main pump 14L, circulates a sufficient amount of hydraulic oil to the hydraulic actuator to be operated, and ensures the driving of the hydraulic actuator to be operated. Note that the controller 30 similarly controls the discharge amount of the right main pump 14R.

With the configuration as described above, the hydraulic system of FIG. 4 can suppress wasteful energy consumption in the main pump 14 in the standby state. Wasteful energy consumption includes pumping loss caused by the hydraulic fluid discharged by the main pump 14 in the center bypass pipe 40 . Further, the hydraulic system of FIG. 4 can reliably supply necessary and sufficient hydraulic oil from the main pump 14 to the hydraulic actuator to be operated when the hydraulic actuator is to be operated.

The control valve 60 is configured to switch the operating device 26 between a valid state and a disabled state. In this embodiment, the control valve 60 is a spool type solenoid valve and is configured to operate according to a current command from the controller 30 .

The enabled state of the operating device 26 is a state in which the operator can operate the operating device 26 to move the related driven body, and the disabled state of the operating device 26 is the state in which the operator operates the operating device 26. It is a state in which the related driven body cannot be moved even if the In other words, when the control valve 60 is open, the operation device 26 is enabled, and when the control valve 60 is closed, operation of the hydraulic actuator by the operation device 26 is disabled.

In the present embodiment, the control valve 60 is an electromagnetic valve capable of switching between a communication state and a disconnection state of the pilot line CD1 that connects the pilot pump 15 and the operating device 26 . Specifically, the control valve 60 is configured to switch between the communication state and the cutoff state of the pilot line CD1 according to a command from the controller 30 . More specifically, the control valve 60 brings the pilot line CD1 into a communicating state at the first valve position, and brings the pilot line CD1 into a blocked state at the second valve position. FIG. 4 shows that the control valve 60 is in the first valve position and that the pilot line CD1 is open.

The control valve 60 may be configured to interlock with a gate lock lever (not shown). Specifically, the pilot line CD1 may be disconnected when the gate lock lever is pushed down, and the pilot line CD1 may be connected when the gate lock lever is pulled up. Further, the control valve 60 may be configured to be able to switch between the enabled state and the disabled state of each of the plurality of operating devices 26 separately.

Using the hydraulic system described above, the controller 30 may be configured to automatically perform braking of the drive of the excavator 100 as needed. Automatically effecting braking of a drive includes, for example, forcibly slowing down or stopping movement of that drive even if the operating device 26 associated with that drive is operated. You can stay.

The controller 30 may be configured, for example, to automatically brake the driving unit when the object detection device 70 detects an object. In this case, the drive section may include, for example, at least one of the turning hydraulic motor 2A and the traveling hydraulic motor 2M. Braking of the drive unit is realized by, for example, switching the pilot line CD1 from the communication state to the disconnection state by the control valve 60 while the operation device 26 is being operated. This is because the control valve corresponding to the operating device 26 that is being operated returns to the neutral valve position. Note that braking the drive unit may include at least one of reducing the operating speed of the drive unit and stopping the movement of the drive unit.

"When braking the drive unit" means, for example, when the operating speed of the drive unit is reduced, when the movement of the drive unit is stopped, and when the stop of the drive unit is maintained. may contain

It should be noted that such a hydraulic system may employ an electric operating lever having an electric pilot circuit instead of a hydraulic operating lever. In this case, the lever operation amount of the electric operation lever is input to the controller 30 as an electric signal, for example. A solenoid valve is arranged between the pilot pump 15 and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electrical signal from controller 30 . With this configuration, when a manual operation is performed using the electric operation lever, the controller 30 controls the solenoid valves with an electric signal corresponding to the lever operation amount to increase or decrease the pilot pressure, thereby moving each control valve. be able to.

Next, the relationship between the control valve 60 and the controller 30 will be described with reference to FIG. FIG. 5 is an example of an electric circuit diagram showing the relationship between the control valve and the controller.

A switch 51 and a relay 52 are connected to the controller 30 of this embodiment. The switch 51 has one end connected to the ignition power source 55 and the other end connected to one input terminal of the controller 30 and the relay 52 . Relay 52 is connected between switch 51 and control valve 60 .

The switch 51 is turned ON (conducting) or OFF (blocking) according to the operation of the gate lock lever.

In this embodiment, when the switch 51 is turned on by operating the gate lock lever, the control valve 60 and the ignition power source 55 are electrically connected via the relay 52, power is supplied to the control valve 60, and the control valve 60 is in communication. At this time, the relay 52 is in the ON state (conduction).

When the switch 51 is turned on, a high level (hereinafter referred to as H level) signal is input from the ignition power supply 55 to the controller 30 via the switch 51 . Based on this signal, the controller 30 detects that the control valve 60 is in the open state.

Further, in the present embodiment, when the switch 51 is turned off by operating the gate lock lever, the control valve 60 and the ignition power source 55 are cut off, power supply to the control valve 60 is stopped, and the control valve 60 is turned off. is blocked.

When the switch 51 is turned off, the H level signal input from the ignition power supply 55 to the controller 30 is inverted to low level (hereinafter referred to as L level). The controller 30 detects that the control valve 60 is in the closed state from this L level signal.

Thus, the switch 51 of the present embodiment switches the state of the control valve 60 from the communicating state to the blocking state or from the blocking state to the communicating state according to the operation of the gate lock lever.

The relay 52 controls conduction and interruption between the switch 51 and the control valve 60 according to the control signal output from the switching section 31 of the controller 30 .

More specifically, when the determining unit 33 determines that the operation of the operating device 26 is an erroneous operation, the relay 52 switches between the switch 51 and the The control valve 60 is shut off, and the control valve 60 is brought into the shut-off state.

The case where the physical quantity changes due to the operation of the operating device 26 is the case where the operating device 26 is in the enabled state, indicating that the control valve 60 is in the communicating state.

In other words, the switching of the state of the control valve 60 using the relay 52 of the present embodiment is applied when the control valve 60 is brought into the communication state by the switch 51 .

The relay 52 has one input terminal connected to the other end of the switch 51 and the other input terminal connected to the controller 30 . Also, the output terminal of the relay 52 is connected to the control valve 60 .

In this embodiment, when the switch 51 is in the ON state and the switch 51 and the control valve 60 are electrically connected via the relay 52, the control valve 60 is in the communication state. That is, the operating device 26 is activated.

Further, when the connection between the switch 51 and the control valve 60 is cut off by the relay 52, even if the switch 51 is in the ON state, electric power is not supplied to the control valve 60, and the control valve 60 is in the cut-off state. . That is, the operating device 26 is disabled.

As described above, in the present embodiment, even when the control valve 60 is in the open state by the gate lock lever, if the controller 30 determines that the operation of the operation device 26 is an erroneous operation, the controller 30 performs control. Valve 60 can be placed in a closed state. Therefore, according to this embodiment, safety can be improved compared to the case where the state of the control valve 60 is controlled only by the gate lock lever.

Next, operation of the shovel 100 of this embodiment will be described with reference to FIG. FIG. 6 is a first flowchart for explaining the operation of the excavator of the embodiment.

The controller 30 of the excavator 100 executes the process of FIG. 6 when the control valve (gate lock valve) 60 is in the closed state and the engine is on.

In this embodiment, for example, when the operator inserts the key into the key cylinder of the excavator 100 and rotates the key to the first position, the excavator 100 is powered on and the controller 30 is activated. After that, even if the key is further rotated to the second position, if the control valve 60 is in the open state, the engine 11 will not be turned ON. is turned ON.

In the present embodiment, this control can prevent the excavator 100 from suddenly moving even if the operation device 26 is erroneously operated immediately after the engine 11 is turned on.

It is also assumed that the operator temporarily suspends the operation inside the cabin 10 during the work. For example, when making a telephone call, when waiting for the arrival of the next dump truck, and the like. In this state, the operator shuts off the control valve 60 by operating the gate lock while maintaining the engine 11 in the ON state (the state in which the engine 11 is rotating). In this way, by putting the control valve 60 in the closed state, even if the operator accidentally tilts the lever during standby, it is possible to prevent the pilot pressure from being applied to the control valves 171 to 176. It does not malfunction.

When the operator keeps the engine 11 in the ON state and shuts off the control valve 60 by operating the gate lock (state in which the operation is temporarily interrupted), the controller 30 locks the gate. It is determined whether or not the control valve 60 has been switched from the closed state to the open state by operating the lever (step S601). In other words, the controller 30 determines whether the switch 51 is turned on. In step S601, if the control valve 60 is not in the open state, the controller 30 waits until the control valve 60 is in the open state.

In step S601, when the control valve 60 is placed in the open state, the controller 30 causes the detection unit 32 to start detecting the control pressure (negative control pressure) detected by the control pressure sensor 19 (step S602). In this state, since the lever included in the operating device 26 is not tilted, the high-pressure hydraulic fluid discharged from the main pump 14 is returned to the tank T through the throttle 18 without flowing into any hydraulic actuator. be Since the return oil to the tank T is restricted by the throttle 18, the negative control pressure detected by the control pressure sensor 19 is high. In such a state, the determination section 33 continues to detect the state of the switch 51 and the state of the negative control pressure.

Subsequently, the controller 30 monitors the switching of the switch 51 to the ON state by the determination unit 33, and the negative control pressure decreases continuously a plurality of times within a predetermined time after the switching to the ON state of the switch 51 below a predetermined value. It is determined whether or not (step S603).

Here, for example, while the operator is operating the gate lock lever to restart the operation, the operator's arm may come into contact with the lever. As described above, if the lever is already tilted due to malfunction during operation of the gate lock lever, the pilot pressure is applied to the control valve corresponding to the tilted lever immediately after the control valve 60 is switched to the communication state. put away.

As a result, hydraulic fluid flows into the hydraulic actuator via the control valve to which the pilot pressure is applied, and the hydraulic actuator suddenly operates. Since the amount of return oil flowing into the throttle 18 decreases due to the flow of hydraulic fluid into the hydraulic actuator, the negative control pressure also decreases.

As a result, in step S603, if the negative control pressure decreases continuously a plurality of times to a predetermined value or less within a predetermined time after the switch 51 is switched to the ON state, the controller 30 determines that an erroneous operation has occurred, and the control valve 60 is cut off (step S604), and the process ends.

As described above, in step S604, the controller 30 causes the determination unit 33 to detect an erroneous operation when the negative control pressure decreases to a predetermined value or less within a predetermined period of time after the switch 51 is switched to the ON state. I judge. The determination unit 33 then notifies the switching unit 31 of a switching instruction for the relay 52 . Further, the determination unit 33 may determine that the operation is erroneous using only a plurality of successive decreases in the negative control pressure within a predetermined time.

Upon receiving this notification, the switching unit 31 outputs to the relay 52 a control signal for switching the control valve 60 from the communication state to the disconnection state. The relay 52 cuts off the connection between the switch 51 and the control valve 60 based on this control signal. By this operation, the power supply to the control valve 60 is stopped, the control valve 60 is switched from the communication state to the disconnection state, and the operating device 26 is disabled.

In step S603, if the negative control pressure is equal to or less than a predetermined value and does not decrease consecutively multiple times within a predetermined period of time, the controller 30 determines that this operation is normal, and maintains the communication state of the control valve 60 ( Step S605), the process ends.

In the present embodiment, by operating the gate lock lever so as to switch the control valve 60 from the cut-off state to the open state, the entrance of the cabin 10 is blocked, and the operator or the like can enter and exit the cabin 10. It becomes difficult to remove. Therefore, in the present embodiment, it is possible to prevent people from getting in and out of the cabin 10 when the operating device 26 is in a valid state.

Further, in the present embodiment, the hatch of the cabin 10 is opened by operating the gate lock lever so as to switch the control valve 60 from the communication state to the cutoff state. Therefore, in the present embodiment, when the operation device 26 is disabled, it becomes easier for a person such as an operator to enter and exit the cabin 10 .

In this embodiment, the controller 30 may control the regulator 13 so that the discharge amount of the main pump 14 is minimized after the control valve 60 is shut off in step S604.

Furthermore, in the present embodiment, the controller 30 may reduce the rotational speed of the engine 11 after the control valve 60 is closed in step S604.

In this embodiment, as described above, the controller 30 outputs the ON signal to the switch 51 so as to bring the control valve 60 into the open state, and then detects the occurrence of an erroneous operation based on the continuous decrease in the negative control pressure within a predetermined time. Determine presence/absence. As a result, for example, even if the viscosity of the hydraulic oil changes due to a change in the outside air temperature, it is possible to reduce the determination error due to the viscosity. By performing such control, after the control valve 60 is shut off, it is possible to reduce the amount of hydraulic oil supplied to the hydraulic actuator that operates in response to the erroneously operated lever, and the time required to completely stop the operation of the excavator 100. can be shortened.

The operation of the excavator 100 will be specifically described below with reference to FIG. FIG. 7 is a diagram for explaining the relationship between the negative control pressure, the operation signal, and the control signal. FIG. 7(A) is a diagram showing the waveform of the negative control pressure, and FIG. 7(B) is a diagram showing the waveform of the signal relating to the judgment of an erroneous operation.

In the example of FIG. 7, the predetermined time is set to a predetermined time ΔT from when the switch 51 is switched to the ON state. In this case, the predetermined time is the time from timing T1 to timing T5. At timing T1, when the switch 51 is turned on and a high level (hereinafter referred to as H level) operation signal SG1 is input, the controller 30 detects that the control valve 60 is open. In the example of FIG. 7A, the negative control pressure is detected at timing T1, timing T2, and timing T3.

In FIG. 7A, when the lever has already been tilted at timing T1, the negative control pressure continuously decreases thereafter. In FIG. 7A, the negative control pressure value at timing T1 is N1 (standby pressure), and the negative control pressure value detected at timing T2 is N2, which is lower than N1. Also, the value of the negative control pressure detected at timing T3 is N3, which is a value lower than N2.

Even during standby, the negative control pressure fluctuates because the hydraulic oil is at high pressure. A threshold value (predetermined value) Nth. Thereby, the determination unit 33 can determine that the variation in the negative control pressure higher than the predetermined value Nth is normal variation during standby. Also, the threshold value (predetermined value) Nth for preventing erroneous determination does not necessarily have to be set.

In the example of FIG. 7A, the negative control pressure is continuously decreased a plurality of times after the operation signal SG1 corresponding to the lever operation amount to the operation device 26 is input.

In the example of FIG. 7A, the period from timing T1 to timing T3 is within a predetermined period of time until timing T5, and furthermore, the detection values (N2, N3) of the negative control pressure are threshold values for preventing erroneous judgment ( (predetermined value) Nth or less.

Therefore, at timing T3, the controller 30 determines that an erroneous operation has occurred when the gate lock lever is operated at timing T1, and as shown in FIG. The signal SG2 is inverted from low level (hereinafter referred to as L level) to H level.

In this embodiment, when the control signal SG2 is inverted from L level to H level, the relay 52 switches to the cutoff position, and the connection between the switch 51 and the control valve 60 is cut off. As a result, the control valve 60 switches from the communicating state to the blocking state. That is, the operating device 26 is disabled. At this time, since the switch 51 remains ON, the operation signal SG1 maintains the H level.

Therefore, in the present embodiment, the control signal SG2 can be switched to the H level from the timing T1 at which the control valve 60 is opened to the timing T3 earlier than the timing T5. As a result, the control valve 60 is closed, and the generation of pilot pressure to the control valves 171-176 can be suppressed. As a result, all the hydraulic fluid discharged from the main pump 14 passes through the throttle 18, and the negative control pressure is restored at timing T4.

As described above, in the present embodiment, it is determined whether or not the operation on the operation device 26 is an erroneous operation based on whether or not the detected physical quantity continuously changes. Therefore, in the present embodiment, it is not necessary to set a threshold that depends on the environment of the work site of the excavator 100 in judging an erroneous operation, and it is possible to easily judge an erroneous operation.

In addition, in the present embodiment, it is possible to determine whether or not there is an erroneous operation in a short time because it is determined whether or not the operation is erroneous depending on how the physical quantity changes.

In the example of FIG. 7, the control signal SG2 output from the controller 30 to the relay 52 is L level when the control valve 60 is open, and is H level when the control valve 60 is closed. However, the signal is not limited to this. The control signal SG2 may be a signal that becomes H level when the control valve 60 is in the open state and becomes L level when the control valve 60 is in the closed state. In other words, the control signal SG2 may be a signal whose level changes according to the state of the control valve 60. FIG.

In addition, in the example of FIG. 7, each value of the negative control pressures N1, N2, and N3 is set as a physical quantity, but it is not limited to this.

The physical quantity may be, for example, a value indicating the difference between the negative control pressure N1 and the negative control pressure N2. In other words, the differential value (gradient) of the negative control pressure may be used as the physical quantity. In this case, the more the physical quantity continuously decreases, the more rapidly the negative control pressure decreases. Therefore, when the amount of change in the negative control pressure is taken as the physical quantity, the determination unit 33 may determine that an operation is erroneous when the physical quantity continuously decreases.

Also, the integral value of the negative control pressure may be used as the physical quantity. In this case, the amount of increase in the integral value at each timing is calculated, and the amount of increase is calculated from the integral value of the negative control pressure at timing T1, the amount of increase in the integral value of the negative control pressure at timing T2, and the integral value of the negative control pressure at timing T2. Therefore, when the amount of increase in the integrated value of the negative control pressure at timing T3 decreases continuously, it can be said that the negative control pressure is rapidly decreasing.

(another embodiment)
Another embodiment will be described below with reference to FIG. In the present embodiment, the pilot pressure is used as the physical quantity to determine an erroneous operation when restarting the operation of the excavator 100 .

Specifically, in this embodiment, the detection unit 32 of the controller 30 detects the pressure of hydraulic fluid (pilot pressure) detected by the operation pressure sensor 29 . Further, the determination unit 33 determines that the operation of the operation device 26 is an erroneous operation when the pilot pressure increases continuously a plurality of times within a predetermined time after the switch 51 is switched to the ON state at a predetermined value or more.

FIG. 8 is a second flowchart for explaining the operation of the excavator of the embodiment. The state of the excavator 100 when the process shown in FIG. 8 is executed is the same as the state when the process of FIG. 6 is executed, and the process of step S801 of FIG. Since it is the same, the explanation is omitted.

Subsequent to step S801, the controller 30 starts detecting the pilot pressure with the operation pressure sensor 29 through the detection unit 32 (step S802).

Subsequently, the controller 30 uses the determination unit 33 to determine whether or not the pilot pressure has increased continuously a plurality of times within a predetermined time at a predetermined value or more (step S803).

In step S803, if the pilot pressure is equal to or greater than the predetermined value and the pilot pressure increases consecutively multiple times within the predetermined time, the controller 30 proceeds to step S804. Further, in step S803, if the pilot pressure does not increase consecutively a plurality of times within a predetermined time at a predetermined value or more, the controller 30 proceeds to step S805. Further, the determination unit 33 may determine that the operation is erroneous based only on a plurality of successive increases in the pilot pressure within a predetermined time.

The processing of step S804 and the processing of step S805 are the same as the processing of step S604 and the processing of step S605 in FIG. 6, so description thereof will be omitted.

The relationship between the pilot pressure, the operation signal, and the control signal will be described below with reference to FIG. FIG. 9 is a diagram explaining the relationship between the pilot pressure, the operation signal, and the control signal. FIG. 9A is a diagram showing the waveform of the pilot pressure of the excavator 100 to which the present embodiment is applied, and FIG. FIG. 4 is a diagram showing; FIG. 9(C) is a diagram showing the waveform of the pilot pressure in the excavator of the comparative example, and FIG. 9(D) is a diagram showing the waveform of the signal relating to the determination of an erroneous operation in the excavator of the comparative example.

As shown in FIG. 9A, at timing T11, when the switch 51 is turned on and the H-level operation signal SG11 is input, the controller 30 detects that the control valve 60 is in the open state, The determination unit 33 starts to periodically detect the pilot pressure. In the example of FIG. 9A, the pilot pressure is detected at timing T11, timing T12, and timing T13. The predetermined time is set to a predetermined time ΔT from when the switch 51 is switched to the ON state. In this case, the predetermined time is the time from timing T11 to timing T15.

In FIG. 9A, the pilot pressure value at timing T11 is P1, and the pilot pressure value detected at timing T12 is P2, which is higher than P1. Also, the value of the pilot pressure detected at timing T13 is P3, which is higher than P2.

The pilot pressure also fluctuates during standby. A threshold value ( Predetermined value) Pth is set. Thereby, the determination unit 33 can determine that the fluctuation in the pilot pressure lower than the predetermined value is normal fluctuation during standby. Also, the threshold value (predetermined value) Pth for preventing erroneous determination does not necessarily have to be set.

Therefore, in the example of FIG. 9(A), the pilot pressure increases continuously a plurality of times after the operation signal SG11 corresponding to the lever operation amount for the operating device 26 is input.

Further, in the example of FIG. 9A, the period from timing T11 to timing T13 is within a predetermined period of time, and the pilot pressure P3 is equal to or higher than a predetermined value.

Therefore, as shown in FIG. 9B, at timing T13, the controller 30 determines that the operation started at timing T11 is an erroneous operation, and causes the switching unit 31 to invert the control signal SG12 from L level to H level. , the control valve 60 is switched from the open state to the closed state. As a result, in the present embodiment, the control signal SG12 can be switched to the H level at timing T13 earlier than timing T15 from timing T11 at which the control valve 60 is opened. As a result, the control valve 60 is closed, and the generation of pilot pressure to the control valves 171-176 can be suppressed. As a result, hydraulic fluid is cut off between the pilot pump 15 and the operating device 26, so the pilot pressure also decreases at timing T14.

Therefore, in the present embodiment, the period from timing T11 when the control valve 60 is opened to timing T13 when the control signal SG12 goes high is the judgment time required for judging an erroneous operation.

On the other hand, as shown in FIG. 9C, in the comparative example, at the timing Ta, when the switch 51 is turned on and the H level signal SG21 is input, the controller 30 controls the pilot pressure to increase within a certain period of time. First, it is determined whether or not the value is equal to or greater than the threshold TH.

In the example of FIG. 9(C), at timing Tb, which is within a certain period of time from timing Ta, the pilot pressure becomes equal to or higher than the threshold TH, so this operation is determined to be an erroneous operation. A signal SG22 is output to shut off the lock valve.

In this comparative example, it is necessary to set a certain time (threshold of time for judging an erroneous operation) in consideration of the viscosity of hydraulic oil that changes with temperature.

Specifically, for example, when the work site of the shovel 100 is in a cold district or the like, the temperature of the outside air is low, so the viscosity of the hydraulic oil is high. Further, when the work site of the excavator 100 is in a warm region or the like, the temperature of the outside air is higher than in cold regions, so the viscosity of the hydraulic oil is lower than in cold regions.

In such a case, even if the same erroneous operation is performed in the excavator 100, when the viscosity of the hydraulic oil is high, it takes longer for the pilot pressure to reach the threshold TH than when the viscosity of the hydraulic oil is low. It takes.

Therefore, when the viscosity of the hydraulic oil is high, it is necessary to set the time threshold for determining an erroneous operation longer than when the viscosity of the hydraulic oil is low. As described above, in the method of the comparative example, it is necessary to set a threshold for determining an erroneous operation according to the environment, and it is difficult to set an appropriate threshold.

In addition, in the comparative example, when the hydraulic oil is monitored until it reaches the threshold value TH, it is determined that the operation is erroneous, so it takes time to determine. In the example of FIG. 9, the determination time taken to determine an erroneous operation in FIG. 9B is the period from timing T11 to timing T13. On the other hand, the determination time required for an erroneous operation in FIG. 9(D) is the period from timing Ta to timing Tb, and it can be seen that the determination time is long compared to FIG. 9(B).

As described above, in the present embodiment, it is possible to quickly and easily determine an operation error of the excavator 100 without depending on the environment of the work site of the excavator 100 .

(Still another embodiment)
In this embodiment, the physical quantity includes the discharge pressure of a pump provided separately from the main pump 14 .

FIG. 10 is a diagram showing another configuration example of the hydraulic system mounted on the excavator. The hydraulic system shown in FIG. 10 includes a pump 14A apart from the main pump 14. As shown in FIG. The pump 14A is, for example, a spare pump that is added when securing the flow rate when moving actuators other than the actuators (bucket, boom, arm, travel, swing) driven by the hydraulic oil discharged by the main pump 14. is. Another actuator may be, for example, a tiltrotator rotary drive, a compactor, or the like.

The pump 14A supplies hydraulic fluid to the control valve 17A through a hydraulic fluid line. The control valve 17A includes a control valve 177 corresponding to another actuator (hereinafter cylinder) 9A. The control valve 177 is a spool valve that switches the flow of hydraulic fluid to supply the hydraulic fluid discharged by the pump 14A to the cylinder 9A and to discharge the hydraulic fluid in the cylinder 9A to the hydraulic fluid tank.

The discharge pressure sensor 28A detects the discharge pressure of the pump 14A. In this embodiment, the discharge pressure sensor 28A outputs the detected value to the controller 30 . In the following description, the discharge pressure of the pump 14A may be expressed as preliminary pump pressure.

In the excavator 100 of this embodiment, the operating device 26A is one of the operating devices 26 and may be used to operate another actuator. The operation device 26A is, for example, a proportional switch provided on an operation lever, an operation pedal, or the like.

The operating device 26A generates pilot pressure acting on the right pilot port of the control valve 177 (hereinafter referred to as right pilot pressure) and pilot pressure acting on the left pilot port of the control valve 177 (hereinafter referred to as left pilot pressure). The right pilot pressure of the control valve 177 is, for example, a pilot pressure for extending or retracting the cylinder 9A, and the left pilot pressure of the control valve 177 is, for example, a pilot pressure for retracting or extending the cylinder 9A. be.

The proportional valves 65L and 65R are valves that adjust the pilot pressure generated by the pilot pump 15 according to the operation amount of the operating device 26A. The proportional valve 65L receives the left pilot pressure generated by the pilot pump 15 as the primary pressure, and adjusts the adjusted pilot pressure according to the operation amount of the operating device 26A (specifically, the opening degree of the cushion valve) as the secondary pressure. Act on the left pilot port of control valve 177 . The proportional valve 65R receives the right pilot pressure generated by the pilot pump 15 as the primary pressure, and applies the adjusted pilot pressure to the right pilot port of the control valve 177 as the secondary pressure according to the operation amount of the operating device 26A.

The controller 30 of the present embodiment may use the discharge pressure detected by the discharge pressure sensor 28</b>A instead of the operation pressure detected by the operation pressure sensor 29 to determine an erroneous operation of the excavator 100 . Further, in the present embodiment, in addition to the operation pressure detected by the operation pressure sensor 29, the discharge pressure detected by the discharge pressure sensor 28A at the time of determination by the determination unit 33 is equal to or higher than a predetermined value within a predetermined time. It may also be determined whether or not the number has increased consecutively multiple times.

Specifically, the determining unit 33 determines whether the negative control pressure decreases continuously multiple times within a predetermined time at a predetermined value or higher, or when the discharge pressure of the pump 14A continuously increases multiple times at a predetermined value or higher. First, the operation on the operating device 26 is determined as an erroneous operation.

The relationship between the discharge pressure of the pump 14A, the operation signal, and the control signal will be described below with reference to FIG. FIG. 11 is a diagram for explaining the relationship between the discharge pressure of the standby pump, the operation signal, and the control signal. FIG. 11A is a diagram showing the waveform of the discharge pressure of the pump 14A of the excavator 100 to which the present embodiment is applied, and FIG. is a diagram showing the waveform of .

As shown in FIG. 11A, at timing T21, the switch 51 is turned on based on the operation of the gate lock lever by the operator, and when the H-level operation signal SG31 is input, the controller 30 causes the control valve 60 to open. Detecting that the communication state has been established, the determination unit 33 starts to periodically detect the discharge pressure of the pump 14A. In the example of FIG. 11A, the discharge pressure of the pump 14A is detected at timing T21, timing T22, and timing T23. The predetermined time is set to a predetermined time ΔTa from when the switch 51 is switched to the ON state. In this case, the predetermined time is the time from timing T21 to timing T25.

In FIG. 11A, the value of the discharge pressure of the pump 14A at timing T21 is P11, and the value of the discharge pressure of the pump 14A detected at timing T22 is P21, which is higher than P11. Also, the value of the discharge pressure of the pump 14A detected at timing T23 is P31, which is higher than P21.

The discharge pressure of the pump 14A also fluctuates during standby. In order to prevent the judging unit 33 from judging a small fluctuation in the discharge pressure of the pump 14A during standby as a continuous increase several times, the pressure value slightly higher than the discharge pressure P11 of the pump 14A during standby is erroneously set. A threshold value (predetermined value) Pth1 for preventing determination is set. As a result, the determination unit 33 can determine that fluctuations in the discharge pressure of the pump 14A that are lower than the predetermined value are normal fluctuations during standby. Also, the threshold value (predetermined value) Pth1 for preventing erroneous determination does not necessarily have to be set.

In the example of FIG. 11(A), the discharge pressure of the pump 14A increases continuously a plurality of times after the operation signal SG31 corresponding to the lever operation amount for the operation device 26 is input.

After that, in the example of FIG. 11A, the period from timing T21 to timing T23 is within a predetermined period of time, and the pilot pressure P31 is equal to or higher than a predetermined value.

Therefore, as shown in FIG. 11B, at timing T23, the controller 30 determines that the operation started at timing T21 is an erroneous operation, and causes the switching unit 31 to invert the control signal SG32 from L level to H level. .

In this embodiment, when the control signal SG32 is inverted from L level to H level, the relay 52 switches to the cutoff position, and the connection between the switch 51 and the control valve 60 is cut off. As a result, the connection between the relay 52 and the control valve 60 is cut off, and the control valve 60 switches from the communication state to the cutoff state. That is, the operating device 26 is disabled.

As a result, in the present embodiment, the control signal SG32 can be switched to the H level at timing T23 earlier than timing T25 from timing T21 at which the control valve 60 is opened.

The predetermined value for the negative control pressure and the predetermined value for the discharge pressure of the pump 14A are different values.

Further, in the present embodiment, the determination unit 33 determines that the pilot pressure continuously increases multiple times within a predetermined time at a predetermined value or higher, or the discharge pressure of the pump 14A continuously increases multiple times at a predetermined value or higher. If so, the operation on the operation device 26 is determined to be an erroneous operation.

Note that the predetermined value for the pilot pressure and the predetermined value for the discharge pressure of the pump 14A are different values.

In this embodiment, an operation error is determined when each of the two types of physical quantities satisfies the above-described conditions within a predetermined period of time. Therefore, in the present embodiment, for example, even if negative control pressure detection fails or pilot pressure detection fails, an erroneous operation can be determined, and safety can be improved.

Further, the physical quantity may be, for example, an integrated value of each of the negative control pressure, the pilot pressure, the discharge pressure of the pump 14A, and the discharge pressure of the main pump 14, or may be a differential value.

Further, in each of the above-described embodiments, the controller 30 causes the switching unit 31 to cut off the connection between the control valve 60 and the switch 51 when the determination unit 33 determines that the operation is erroneous, thereby turning the operation device 26 on. Although the operation device 26 is disabled, the operation device 26 may be disabled other than when an erroneous operation is determined.

Specifically, for example, when the object detection device 70 detects a predetermined object within a predetermined area set around the excavator 100, the controller 30 changes the control signal output from the switching unit 31 from L level to At H level, the control valve 60 may be shut off and the operating device 26 may be disabled.

By controlling in this way, for example, when a person, an animal, or the like is detected in the area around the excavator 100, the operation of the excavator 100 can be automatically stopped.

Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. can be added.

Reference Signs List 11 engine 14 main pump 19 control pressure sensor 28 discharge pressure sensor 30 controller 31 switching unit 32 detection unit 33 determination unit 60 control valve 100 excavator

Claims (6)

a detection unit that detects a physical quantity that changes according to the content of an operation performed on an operation device that operates an actuator;
and a determination unit that determines whether or not the operation is an erroneous operation according to whether or not the physical quantity has increased or decreased continuously. The physical quantity is a negative control pressure,
The determination unit is
2. The excavator according to claim 1, wherein said operation is determined to be an erroneous operation when said negative control pressure continuously decreases below a predetermined value within a predetermined time. The physical quantity is pilot pressure,
The determination unit is
2. The excavator according to claim 1, wherein said operation is determined as an erroneous operation when said pilot pressure continuously increases to a predetermined value or more within a predetermined time. The physical quantity is
is the discharge pressure of a pump that is provided separately from the main pump and that supplies hydraulic oil to another actuator;
The determination unit is
4. The excavator according to claim 2, wherein said operation is determined as an erroneous operation when the discharge pressure of said pump continuously increases above a predetermined value within a predetermined time. a control valve that connects or disconnects a pilot line that connects the operating device and the pilot pump;
a switching unit that switches the pilot line from a communication state to a disconnection state or from a disconnection state to a communication state using the control valve;
The switching unit is
The excavator according to any one of claims 1 to 4, wherein the pilot line is switched from a communication state to a disconnection state when the operation is determined to be an erroneous operation. having an object detection unit that detects a predetermined object within a set predetermined area;
The switching unit is
6. The excavator according to claim 5, wherein said pilot line is switched from a communication state to a cut-off state when said predetermined object within said predetermined area is detected by said object detection unit.

Images