JP2022157910A - Shovel - Google Patents

Abstract

To provide a shovel that improves workability of air bleeding work.SOLUTION: A shovel comprises an upper turning body, a lower traveling body, a directional control valve 176, and a control device 30 for controlling the directional control valve. The control device supplies pilot pressure from both sides of a spool of the directional control valve when the directional control valve is in a neutral state.SELECTED DRAWING: Figure 4A

Description

The present disclosure relates to excavators.

A working machine comprising a lower traveling structure, an upper revolving structure that can swivel with respect to the lower traveling structure, an attachment attached to the upper revolving structure, a swing hydraulic motor that rotates the upper revolving structure, and a hydraulic actuator that drives the attachment. It has been known. Patent Literature 1 discloses a fluid pressure control device capable of removing air from a pilot chamber.

JP 2016-75341 A

By the way, when the excavator is assembled and hydraulic oil is supplied to the hydraulic circuit, air is mixed in the pilot line. Therefore, an air bleeding operation is performed to remove air from the pilot line.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a shovel that improves the workability of air bleeding work.

An excavator according to an embodiment of the present invention is an excavator that includes an upper rotating body, a lower running body, a directional control valve, and a control device that controls the directional control valve, wherein the control device With the control valve in neutral, pilot pressure is supplied from both sides of the spool of the directional control valve.

ADVANTAGE OF THE INVENTION According to this invention, the shovel which improves the workability|operativity of air bleeding work can be provided.

1 is a side view of a shovel according to an embodiment of the present invention; FIG. Figure 2 is a top view of the shovel of Figure 1; 2 is a diagram showing a configuration example of a hydraulic system mounted on the excavator of FIG. 1; FIG. FIG. 4 is a diagram of part of the hydraulic system for operating the arm cylinder; FIG. 4 is a diagram of part of the hydraulic system for the boom cylinder; FIG. 4 is a diagram of part of the hydraulic system for the bucket cylinder; FIG. 4 is a diagram of part of the hydraulic system for the swing hydraulic motor; 4 is a flowchart for explaining an air bleeding operation; 4 is an example of a graph showing the relationship between the stroke amount of the spool in the control valve and the pilot pressure; It is a schematic block diagram explaining an example of a control valve.

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. The crawler 1</b>C is driven by a traveling hydraulic motor 2</b>M 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.

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

A boom 4 is attached to the upper revolving 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 attachment AT, 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 . The boom cylinder 7, arm cylinder 8, and bucket cylinder 9 constitute an attachment actuator. In the example shown in Figures 1 and 2, the bucket 6 is an excavating bucket, but it may also be a skeleton bucket or (a gravel bucket). Also, the bucket 6 may have a bucket tilt mechanism.

The upper swing body 3 is provided with a cabin 10 as an operator's cab and is equipped with a power source such as an engine 11 . Inside the cabin 10, an operation device 26, a controller 30, an operation method switching device SD, and the like are provided. A space recognition device 70 and the like are attached to the upper swing body 3 . In this document, for the sake of convenience, the side of the upper rotating body 3 to which the attachment AT is attached is referred to as the front, and the side to which the counterweight is attached is referred to as the rear.

The space recognition device 70 is configured to recognize objects existing in a three-dimensional space around the excavator 100 . Further, the space recognition device 70 may be configured to calculate the distance from the space recognition device 70 or the excavator 100 to the recognized object. The space recognition device 70 includes, for example, an ultrasonic sensor, a millimeter wave radar, an imaging device, a LIDAR, a range image sensor, an infrared sensor, etc., or any combination thereof. The imaging device is, for example, a monocular camera or a stereo camera. In this embodiment, the space recognition 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 . An upper sensor that recognizes an object existing in the space above the upper swing body 3 may be attached to the excavator 100 .

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

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 each time the push button switch is pressed, the operation lever is switched between the first operation method and the second operation method. It is configured so that the operation method can be switched. For example, in the first operation method, the arm 5 is opened when the left control lever 26L (see FIG. 3) is tilted forward, and the arm 5 is closed when the left control lever 26L is tilted backward. A left turn is executed when the left control lever 26L is tilted leftward, and a right turn is executed when the left control lever 26L is tilted rightward. In the first operation method, the boom 4 is lowered when the right operating lever 26R (see FIG. 3) is tilted forward, and the boom 4 is raised when the right operating lever 26R is tilted backward. The bucket 6 is closed when the right operating lever 26R is tilted leftward, and the bucket 6 is opened when the right operating lever 26R is tilted rightward. On the other hand, in the second operation method, a right turn is executed when the left control lever 26L (see FIG. 3) is tilted forward, and a left turn is executed when the left control lever 26L is tilted backward. The arm 5 is opened when the left operating lever 26L is tilted leftward, and the arm 5 is closed when the left operating lever 26L is tilted rightward.

For example, the operator of the excavator 100 selects the first operation method when performing excavation work using an excavation bucket, and selects the second operation method when performing gravel removal work using a skeleton bucket (removal bucket). You may choose.

Controller 30 is a control device for controlling excavator 100 . In this embodiment, the controller 30 is configured by a computer including a CPU, a volatile memory device, a non-volatile memory device, and the like. Then, the controller 30 reads a program corresponding to each function from the nonvolatile storage device, loads it into the volatile storage device, and causes the CPU to execute the corresponding process. Each function includes, for example, a machine guidance function that guides the manual operation of the excavator 100 by the operator, and supports the manual operation of the excavator 100 by the operator or causes the excavator 100 to operate automatically or autonomously. Including machine control functions such as The controller 30 includes a contact avoidance function that automatically or autonomously operates or stops the excavator 100 in order to avoid contact between the excavator 100 and an object present within the monitoring range around the excavator 100 . You can Objects around the excavator 100 are monitored not only within the monitoring range but also outside the monitoring range.

Next, a configuration example of the hydraulic system mounted on the excavator 100 will be described with reference to FIG. 3 . FIG. 3 is a diagram showing a configuration example of a hydraulic system mounted on the excavator 100. As shown in FIG. FIG. 3 shows the mechanical driveline, hydraulic lines, pilot lines and electrical control system in double, solid, dashed and dotted lines respectively.

A 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 operation device 26, a discharge pressure sensor 28, an operation sensor 29, a controller 30, and the like.

In FIG. 3, the hydraulic system is configured such that hydraulic oil can be circulated from the main pump 14 driven by the engine 11 to the hydraulic oil tank via the center bypass line 40 or the 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 is configured to supply hydraulic fluid to the control valve unit 17 via a hydraulic fluid line. In this embodiment, the main pump 14 is a swash plate type variable displacement hydraulic pump.

The regulator 13 is configured to be able to control 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 is an example of a pilot pressure generating device, and is configured to supply hydraulic fluid to hydraulic control equipment via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generator may be implemented by the main pump 14 . That is, the main pump 14 may have a function of supplying hydraulic fluid to various hydraulic control devices via a pilot line in addition to the function of supplying hydraulic fluid to the control valve unit 17 via the hydraulic fluid line. In this case, 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 171-176. 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 unit 17 is configured to selectively supply hydraulic fluid discharged from the main pump 14 to one or more hydraulic actuators through control valves 171-176. The control valves 171 to 176, for example, control the flow rate of hydraulic fluid flowing from the main pump 14 to the hydraulic actuator and the flow rate of hydraulic fluid flowing from the hydraulic actuator to the hydraulic fluid tank. 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 operating device 26 is configured so that an operator can 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 operation device is configured to supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the 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 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 content of the operation of the operation device 26 by the operator. In this embodiment, the operation sensor 29 detects the operation direction and the amount of operation of the operation device 26 corresponding to each actuator, and outputs the detected values to the controller 30 .

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

The control valve 171 controls the flow of hydraulic fluid in order to supply the hydraulic fluid discharged by the left main pump 14L to the left traveling hydraulic motor 2ML and to discharge the hydraulic fluid discharged by the left traveling hydraulic motor 2ML to the hydraulic fluid tank. It is a switching spool valve.

The control valve 172 controls the flow of hydraulic fluid in order to supply the hydraulic fluid discharged by the right main pump 14R to the right traveling hydraulic motor 2MR and to discharge the hydraulic fluid discharged by the right traveling hydraulic motor 2MR to the hydraulic fluid tank. It is a switching spool valve.

The control valve 173 supplies the hydraulic oil discharged by the left main pump 14L to the swing hydraulic motor 2A and discharges the hydraulic oil discharged by the swing hydraulic motor 2A to the hydraulic oil tank. 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 supplies hydraulic fluid to the 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, and 175L. can. The right parallel pipeline 42R is a hydraulic oil line parallel to the right center bypass pipeline 40R. The right parallel line 42R supplies 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, and 175R. can.

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 power (absorption horsepower) of the main pump 14 represented by the product of the discharge pressure and the discharge amount 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 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 operation 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

In the example shown in FIG. 3, the left control lever 26L functions as an arm control lever when operated in the front-rear direction, and functions as a turning control lever when operated in the left-right direction.

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 operating 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.

In the example shown in FIG. 3, the right operating lever 26R functions as a boom operating lever when operated in the front-rear 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. 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 sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the content of the operator's operation of the left operation lever 26L in the front-rear direction, and outputs the detected value to the controller 30. FIG. The details of the operation are, for example, the lever operation direction, lever operation amount (lever operation angle), and the like.

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

The controller 30 receives the output of the operation sensor 29 , outputs a control command to the regulator 13 as necessary, and changes the discharge amount of the main pump 14 . The controller 30 also receives the output of a control pressure sensor 19 provided upstream of the throttle 18 and outputs a control command to the regulator 13 as necessary to change the discharge amount of the main pump 14 . 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 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 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. 3 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. 3 can reliably supply necessary and sufficient working oil from the main pump 14 to the hydraulic actuator to be operated when the hydraulic actuator is to be operated.

A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are attached to the boom cylinder 7 . The arm cylinder 8 is attached with an arm rod pressure sensor S8R and an arm bottom pressure sensor S8B. A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B are attached to the bucket cylinder 9 . The boom rod pressure sensor S7R, boom bottom pressure sensor S7B, arm rod pressure sensor S8R, arm bottom pressure sensor S8B, bucket rod pressure sensor S9R, and bucket bottom pressure sensor S9B are also collectively referred to as "cylinder pressure sensors." A left swing pressure sensor S10L and a right swing pressure sensor S10R are attached to the swing hydraulic motor 2A.

The boom rod pressure sensor S7R detects the pressure of the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom rod pressure"), and the boom bottom pressure sensor S7B detects the pressure of the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom rod pressure"). , “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 "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 "arm rod pressure"). , “arm bottom pressure”) is detected. The bucket rod pressure sensor S9R detects the pressure of the rod side oil chamber of the bucket cylinder 9 (hereinafter referred to as "bucket rod pressure"), and the bucket bottom pressure sensor S9B detects the pressure of the bottom side oil chamber of the bucket cylinder 9 (hereinafter referred to as "bucket rod pressure"). , “bucket bottom pressure”) is detected. The left swing pressure sensor S10L detects the pressure of hydraulic fluid at the left port of the swing hydraulic motor 2A. The right turning pressure sensor S10R detects the pressure of hydraulic fluid at the right port of the turning hydraulic motor 2A. A value detected by each sensor is transmitted to the controller 30 .

Next, with reference to FIGS. 4A to 4D, the configuration for the controller 30 to operate the actuators by the machine control function will be described. 4A-4D are partial cutaway views of the hydraulic system. Specifically, FIG. 4A is a view of the hydraulic system portion related to the operation of the arm cylinder 8, and FIG. 4B is a view of the hydraulic system portion related to the operation of the boom cylinder 7. As shown in FIG. FIG. 4C is a diagram extracting a hydraulic system portion relating to the operation of the bucket cylinder 9, and FIG. 4D is a diagram extracting a hydraulic system portion relating to the operation of the turning hydraulic motor 2A.

The hydraulic system includes a proportional valve 31, as shown in FIGS. 4A-4D. The proportional valve 31 includes proportional valves 31AL-31DL and 31AR-31DR.

The proportional valve 31 functions as a control valve for machine control. The proportional valve 31 is arranged in a pipeline 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 pipeline. In this embodiment, the proportional valve 31 operates according to a control command output by the controller 30 . Therefore, the controller 30 supplies the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the proportional valve 31, regardless of the operation of the operating device 26 by the operator. can. The controller 30 can then cause the pilot pressure generated by the proportional valve 31 to act on the pilot port of the corresponding control valve.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to the specific operating device 26 even when the specific operating device 26 is not operated. Further, even when a specific operating device 26 is being operated, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operating device 26 .

For example, the left operating lever 26L is used to operate the arm 5, as shown in FIG. 4A. Specifically, the left operation lever 26L utilizes hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure to the pilot port of the control valve 176 according to the operation in the front-rear direction. More specifically, when the left operation lever 26L is operated in the arm closing direction (backward), the pilot pressure corresponding to the amount of operation is applied to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. act. Further, when the left operating lever 26L is operated in the arm opening direction (forward direction), a pilot pressure corresponding to the amount of operation is applied to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

A switch NS is provided on the left operating lever 26L. In this embodiment, the switch NS is a push button switch provided at the tip of the left operating lever 26L. The operator can operate the left operating lever 26L while pressing the switch NS. The switch NS may be provided on the right operating lever 26R, or may be provided at another position inside the cabin 10 .

The operation sensor 29LA detects the content of the operator's operation of the left operation lever 26L in the front-rear direction, and outputs the detected value to the controller 30. FIG.

The proportional valve 31AL operates according to a control command (current command) output by the controller 30 . Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 through the proportional valve 31AL to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. The proportional valve 31AR operates according to a control command (current command) output by the controller 30. Then, it adjusts the pilot pressure of hydraulic oil introduced from the pilot pump 15 through the proportional valve 31AR into the left pilot port of the control valve 176L and the right pilot port of the control valve 176R. The proportional 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 proportional 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.

A pilot pressure sensor 32AL for detecting pilot pressure is provided on a pilot line connecting the proportional valve 31AL and one port of the control valve 176 (the right port of the control valve 176L and the left port of the control valve 176R). there is A pilot pressure sensor 32AR for detecting pilot pressure is provided on a pilot line connecting the proportional valve 31AR and the other port of the control valve 176 (the left port of the control valve 176L and the right port of the control valve 176R). there is Values detected by each of pilot pressure sensors 32AL and 32AR are transmitted to controller 30 .

With this configuration, the controller 30 supplies hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL in response to the arm closing operation by the operator. can. In addition, the controller 30 supplies hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL, regardless of the arm closing operation by the operator. can. That is, the controller 30 can close the arm 5 according to the arm closing operation by the operator or regardless of the arm closing operation by the operator.

Further, the controller 30 can supply the hydraulic fluid discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR in response to the arm opening operation by the operator. In addition, the controller 30 supplies hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR, regardless of the arm opening operation by the operator. can. That is, the controller 30 can open the arm 5 according to the arm opening operation by the operator or regardless of the arm opening operation by the operator.

In addition, with this configuration, the controller 30 can operate the closing side pilot port of the control valve 176 (the left side pilot port of the control valve 176L and the By reducing the pilot pressure acting on the right pilot port of the control valve 176R, the closing operation of the arm 5 can be forcibly stopped. The same applies to the case where the opening operation of the arm 5 is forcibly stopped while the operator is performing the arm opening operation.

Alternatively, the controller 30 may optionally control the proportional valve 31AR to control the valve 31AR on the opposite side of the closed side pilot port of the control valve 176, even when the operator is performing an arm closing operation. By increasing the pilot pressure acting on the opening side pilot port of the control valve 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) and forcibly returning the control valve 176 to the neutral position, the arm 5 may be forcibly stopped. The same applies to the case of forcibly stopping the opening operation of the arm 5 when the arm opening operation is performed by the operator.

Further, although the description with reference to FIGS. 4B to 4D below is omitted, when the operation of the boom 4 is forcibly stopped while the operator is performing the boom raising operation or the boom lowering operation, the operation When the movement of the bucket 6 is forcibly stopped when the bucket closing operation or bucket opening operation is performed by the operator, and when the turning operation of the upper rotating body 3 is performed by the operator The same applies to the case of forced termination. The same applies to the case where the running motion of the lower running body 1 is forcibly stopped while the running operation is being performed by the operator.

Moreover, as shown in FIG. 4B, the right operating lever 26R is used to operate the boom 4. As shown in FIG. Specifically, the right operating lever 26R utilizes the hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure to the pilot port of the control valve 175 according to the operation in the front-rear direction. More specifically, when the right operating lever 26R is operated in the boom raising direction (backward), the pilot pressure corresponding to the amount of operation acts on the left pilot port of the control valve 175R. Further, when the right operation lever 26R is operated in the boom lowering direction (forward direction), a pilot pressure corresponding to the amount of operation is applied to the right pilot port of the control valve 175R.

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

The proportional valve 31BL operates according to a control command (current command) output by the controller 30. Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL. The proportional valve 31BR operates according to a control command (current command) output by the controller 30 . Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR. The proportional valve 31BL can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position. Also, the proportional valve 31BR can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position.

A pilot pressure sensor 32BL for detecting pilot pressure is provided in a pilot line that connects the proportional valve 31BL and one port of the control valve 175 (the left port of the control valve 175R). A pilot pressure sensor 32BR for detecting pilot pressure is provided on a pilot line connecting the proportional valve 31BR and the other port of the control valve 175 (the right port of the control valve 175R). The values detected by each of pilot pressure sensors 32BL and 32BR are transmitted to controller 30 .

With this configuration, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL in response to the boom raising operation by the operator. In addition, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL regardless of the operator's operation to raise the boom. That is, the controller 30 can raise the boom 4 according to the operator's boom raising operation or regardless of the operator's boom raising operation.

Further, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR in response to the boom lowering operation by the operator. In addition, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR regardless of the boom lowering operation by the operator. That is, the controller 30 can lower the boom 4 according to the operator's boom lowering operation or regardless of the operator's boom lowering operation.

In addition, in FIG. 4B, the controller 30 controls the proportional valves 31BL and 31BR and supplies the pilot pressure to the control valve 175R. Similarly, controller 30 controls a proportional valve (not shown) to provide pilot pressure to control valve 175L.

The right operating lever 26R is also used to operate the bucket 6, as shown in FIG. 4C. Specifically, the right operating lever 26R utilizes the hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure to the pilot port of the control valve 174 according to the operation in the left-right direction. More specifically, the right operating lever 26R applies a pilot pressure corresponding to the amount of operation to the left pilot port of the control valve 174 when operated in the bucket closing direction (leftward direction). Further, when the right operation lever 26R is operated in the bucket opening direction (rightward), a pilot pressure corresponding to the amount of operation is applied to the right pilot port of the control valve 174. As shown in FIG.

The operation sensor 29 RB detects the content 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 proportional valve 31CL operates according to a control command (current command) output by the controller 30 . Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL. The proportional valve 31CR operates according to a control command (current command) output by the controller 30 . Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR. The proportional valve 31CL can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position. Similarly, the proportional valve 31CR can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position.

A pilot pressure sensor 32CL for detecting pilot pressure is provided in a pilot line that connects the proportional valve 31CL and one port of the control valve 174 (the left port of the control valve 174). A pilot pressure sensor 32CR for detecting pilot pressure is provided in a pilot line connecting the proportional valve 31CR and the other port of the control valve 174 (the right port of the control valve 174). Values detected by each of the pilot pressure sensors 32CL and 32CR are sent to the controller 30 .

With this configuration, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL in response to the bucket closing operation by the operator. Further, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL regardless of the bucket closing operation by the operator. That is, the controller 30 can close the bucket 6 according to the bucket closing operation by the operator or regardless of the bucket closing operation by the operator.

Further, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR in response to the bucket opening operation by the operator. Further, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR regardless of the bucket opening operation by the operator. That is, the controller 30 can open the bucket 6 according to the bucket opening operation by the operator or regardless of the bucket opening operation by the operator.

The left operating lever 26L is also used to operate the turning mechanism 2, as shown in FIG. 4D. Specifically, the left operation lever 26L utilizes the hydraulic oil discharged by the pilot pump 15 to apply pilot pressure to the pilot port of the control valve 173 according to the operation in the left-right direction. More specifically, the left operation lever 26L applies a pilot pressure corresponding to the amount of operation to the left pilot port of the control valve 173 when it is operated in the left turning direction (leftward direction). Further, when the left operating lever 26L is operated in the right turning direction (rightward direction), the pilot pressure corresponding to the amount of operation is applied to the right pilot port of the control valve 173 .

The operation sensor 29LB detects the content 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 proportional valve 31DL operates according to a control command (current command) output by the controller 30 . Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL. The proportional valve 31DR operates according to a control command (current command) output by the controller 30 . Then, it adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR. The proportional valve 31DL can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position. Similarly, the proportional valve 31DR can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position.

A pilot pressure sensor 32DL for detecting pilot pressure is provided in a pilot line that connects the proportional valve 31DL and one port of the control valve 173 (the left port of the control valve 173). A pilot pressure sensor 32DR for detecting pilot pressure is provided in a pilot line connecting the proportional valve 31DR and the other port of the control valve 173 (the right port of the control valve 173). Values detected by each of pilot pressure sensors 32DL and 32DR are transmitted to controller 30 .

With this configuration, the controller 30 can supply the hydraulic fluid discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL in response to the left turning operation by the operator. In addition, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL regardless of the left turning operation by the operator. That is, the controller 30 can turn the turning mechanism 2 to the left according to the left turning operation by the operator or regardless of the left turning operation by the operator.

In addition, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR in response to the right turning operation by the operator. In addition, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR regardless of the right turning operation by the operator. That is, the controller 30 can rotate the turning mechanism 2 to the right according to the right turning operation by the operator or regardless of the right turning operation by the operator.

The excavator 100 may be configured to automatically advance and reverse the undercarriage 1 . In this case, the hydraulic system portion related to the operation of the left travel hydraulic motor 2ML and the hydraulic system portion related to the operation of the right travel hydraulic motor 2MR may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7 and the like.

Also, although the electric operating lever has been described as the form of the operating device 26, a hydraulic operating lever may be employed instead of the electric operating lever. In this case, the lever operation amount of the hydraulic operation lever may be detected in the form of pressure by a pressure sensor and input to the controller 30 . Also, an electromagnetic valve may be arranged between the operating device 26 as a hydraulic operating lever 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 manual operation is performed using the operating device 26 as a hydraulic operating lever, the operating device 26 can move each control valve by increasing or decreasing the pilot pressure according to the amount of lever operation. . Also, each control valve may be composed of an electromagnetic spool valve. In this case, the electromagnetic spool valve operates according to an electric signal from the controller 30 corresponding to the lever operation amount of the electric operation lever.

Next, the operation of removing air from the pilot line of the excavator 100 will be described with reference to FIG. FIG. 5 is a flow chart for explaining the air bleeding operation. In the following description, an air bleeding operation in the pilot line of the control valve 173 that controls the swing hydraulic motor 2A will be described as an example.

In step S101, the controller 30 determines whether or not the air bleeding mode has been selected. For example, the excavator 100 has an operable display device (not shown), and an operation button for instructing the air bleeding mode is displayed on the investigation screen displayed on the display device. When the operator operates the operation button for instructing the air bleeding mode, the controller 30 determines that the air bleeding mode has been selected. If the air bleeding mode is not selected (S101, No), the process of the controller 30 repeats step S101. If the air bleeding mode is selected (S101, Yes), the process of the controller 30 proceeds to step S102.

In step S102, the controller 30 controls the proportional valves 31DL and 31DR to supply pilot pressure to both ports (left pilot port, right pilot port) of the control valve 173, respectively. Here, the controller 30 controls the proportional valves 31DL and 31DR so that the pilot pressures supplied to both ports of the control valve 173 are equal to or higher than a predetermined pressure.

In step S103, the controller 30 detects the pilot pressure of the left pilot port of the control valve 173 with the pilot pressure sensor 32DL, and detects the pilot pressure of the right pilot port of the control valve 173 with the pilot pressure sensor 32DR.

In step S104, the controller 30 determines whether the differential pressure between the pilot pressure at the left pilot port of the control valve 173 and the pilot pressure at the right pilot port of the control valve 173 is less than a predetermined threshold. If the differential pressure between the pilot pressure at the left pilot port of the control valve 173 and the pilot pressure at the right pilot port of the control valve 173 is not less than the predetermined threshold value (S104, No), the process of the controller 30 proceeds to step S105. If the differential pressure between the pilot pressure of the left pilot port of the control valve 173 and the pilot pressure of the right pilot port of the control valve 173 is less than the predetermined threshold (S104, Yes), the process of the controller 30 proceeds to step S106.

Here, the relationship between the pilot pressure and the spool stroke amount in the control valves 171-176 will be explained using FIG. FIG. 6 is an example of a graph showing the relationship between the stroke amount of the spools in the control valves 171 to 176 and the pilot pressure. In FIG. 6, the horizontal axis indicates the stroke amount of the spool, and the vertical axis indicates the pilot pressure.

As shown in FIG. 6, when the pilot pressure is equal to or lower than a predetermined preset pressure PVmin (for example, 0.4 MPa), the stroke amount of the spool is zero (neutral position). When the pilot pressure exceeds a predetermined preset pressure PVmin, the stroke amount of the spool increases as the pilot pressure increases. When the pilot pressure is a predetermined maximum pilot pressure PVmax, the stroke amount Kmax of the spool is maximized.

In this way, when the differential pressure between the pilot pressure at the left pilot port of the control valve 173 and the pilot pressure at the right pilot port of the control valve 173 is a predetermined threshold value (for example, a value equal to or lower than the preset pressure PVmin), the control valve 173 spool remains in the neutral position. That is, the hydraulic oil supplied from the main pump 14 is not supplied to the swing hydraulic motor 2A, so that the swing hydraulic motor 2A does not rotate.

In other words, the controller 30 determines whether the pilot pressure at the left pilot port of the control valve 173 and the pilot pressure at the right pilot port of the control valve 173 are balanced. Further, the controller 30 determines that there is no balance when the differential pressure between the pilot pressure at the left pilot port of the control valve 173 and the pilot pressure at the right pilot port of the control valve 173 is equal to or greater than a predetermined pressure.

In step S<b>105 , the controller 30 controls the proportional valves 31DL and 31DR to correct and control the pilot pressure supplied to both ports of the control valve 173 . For example, the other pilot pressure may be controlled so as to match the higher or lower pilot pressure. In other words, when the controller 30 determines that the pilot pressure at the left pilot port of the control valve 173 and the pilot pressure at the right pilot port of the control valve 173 are not balanced, the controller 30 controls the proportional valves 31DL and 31DR. balance out. Then, the processing of the controller 30 proceeds to step S106.

In step S<b>106 , the controller 30 determines whether or not a predetermined time has passed since the pilot pressure was supplied to both ports of the control valve 173 . If the predetermined time has not elapsed (S106, No), the process of the controller 30 returns to step S103. When the predetermined time has passed (S106, Yes), the process of the controller 30 returns to step S103.

At step S107, the controller 30 closes the proportional valves 31DL and 31DR. Then, the controller 30 terminates the processing of the air bleeding mode.

FIG. 7 is a schematic diagram illustrating an example of the control valve 173. As shown in FIG.

The center bypass passage 701 is connected to the center bypass pipeline 40 (see FIG. 3). The parallel passage 702 is connected with the parallel conduit 42 (see FIG. 3). The cylinder port 703 is connected to one port of the hydraulic actuator (swing hydraulic motor 2A). The cylinder port 704 is connected to the other port of the hydraulic actuator (swing hydraulic motor 2A). Tank port 705 is connected to a hydraulic oil tank. A check valve 707 is provided in the bridge passage 706 .

Left pilot port 708 is connected to the output of proportional valve 31DL (see FIG. 4D). Right pilot port 709 is connected to the output of proportional valve 31DR (see FIG. 4D).

Spool 710 is configured to be movable rightward by pilot pressure supplied to left pilot port 708 . Also, the spool 710 is configured to be movable leftward by the pilot pressure supplied to the right pilot port 709 . The biasing portion 711 biases the spool 710 to return to the neutral position.

A pilot pressure is supplied from the left pilot port 708 and the spool 710 moves to the right, whereby the notch of the spool 710 communicates the bridge passage 706 and the cylinder port 703 . A notch in the spool 710 communicates the cylinder port 704 with the tank port 705 on the right side. As a result, hydraulic fluid flows from the parallel passage 702 to the cylinder port 703 via the bridge passage 706 and the notch of the spool 710 that communicates the bridge passage 706 and the cylinder port 703 . Hydraulic oil flows from the cylinder port 704 to the right tank port 705 through a notch in the spool 710 that communicates the cylinder port 704 and the right tank port 705 .

Pilot pressure is supplied from the right pilot port 709 , and the notch of the spool 710 communicates the bridge passage 706 and the cylinder port 704 by moving the spool 710 leftward. A notch in the spool 710 communicates the cylinder port 703 with the left tank port 705 . As a result, hydraulic fluid flows from the parallel passage 702 to the cylinder port 704 via the bridge passage 706 and the notch of the spool 710 that communicates the bridge passage 706 and the cylinder port 704 . Hydraulic oil flows from the cylinder port 703 to the left tank port 705 through the notch of the spool 710 that communicates the cylinder port 703 and the left tank port 705 .

Here, as shown in step S102, the pilot pressure is supplied to the left pilot port 708 and the right pilot port 709 so as to be equal to or higher than a predetermined pressure. This allows the spool 710 to maintain its neutral position.

Further, as shown in step S106, a state in which a pilot pressure equal to or higher than a predetermined pressure is supplied to the left and right pilot ports is maintained for a predetermined time. As a result, by supplying a pilot pressure equal to or higher than a predetermined pressure to the left pilot port 708, the air in the pilot line passes through the gap of the spool 710 and is discharged to the tank port 705 (see the dashed arrow). Similarly, by supplying a pilot pressure equal to or higher than a predetermined pressure to the right pilot port 709, the air in the pilot line passes through the gap of the spool 710 and is discharged to the tank port 705 (see the dashed arrow).

As described above, according to the excavator 100 according to the present embodiment, it is possible to perform the operation of removing air from the pilot line. Further, since the spool of the control valve 173 can be kept at the neutral position during the air bleeding operation, the air bleeding operation of the pilot line of the control valve 173 can be performed without the upper rotating body 3 rotating. As a result, it is possible to reduce the work space required for the air bleeding work. In addition, since the operation of removing air from the left and right pilot lines of the control valve 173 can be performed at the same time, the operation time can be shortened.

Although the air bleeding from the pilot line related to the control valve 173 of the swing hydraulic motor 2A has been described as an example, the present invention is not limited to this, and can be applied to the air bleeding work from the pilot line related to the control valves of other hydraulic actuators. be able to. That is, a pilot line related to the control valve 175 of the boom cylinder 7, a pilot line related to the control valve 176 of the arm cylinder 8, a pilot line related to the control valve 174 of the bucket cylinder 9, and a pilot line related to the control valve 171 of the left traveling hydraulic motor 2ML. The same can be applied to the line, the pilot line related to the control valve 172 of the right traveling hydraulic motor 2MR. In addition, since the air bleeding work can be performed simultaneously on the left and right pilot lines of the plurality of control valves 171 to 176, the work time can be shortened. Also, the air bleeding operation can be performed without operating the hydraulic actuator.

100 Excavator 1 Undercarriage 2A Swing hydraulic motor (hydraulic actuator)
2M traveling hydraulic motor (hydraulic actuator)
2ML left travel hydraulic motor (hydraulic actuator)
2MR right travel hydraulic motor (hydraulic actuator)
3 upper rotating body 4 boom 5 arm 6 bucket 7 boom cylinder (hydraulic actuator)
8 arm cylinder (hydraulic actuator)
9 bucket cylinder (hydraulic actuator)
14 Main pump 17 Control valve unit 171-176 Control valve (direction control valve)
30 controller (control device)
31 proportional valve 32 pilot pressure sensor

Claims (7)

an upper rotating body;
a lower running body;
a directional control valve;
and a control device that controls the directional control valve,
The control device is
when the directional control valve is in a neutral state, supplying pilot pressure from both sides of the spool of the directional control valve;
Excavator. an upper rotating body;
a lower running body;
a directional control valve;
and a control device that controls the directional control valve,
The control device is
Having an air bleeding mode for bleeding air from a pilot line that supplies pilot pressure to the directional control valve,
Excavator. The directional control valve has a first pilot port and a second pilot port,
The control device is
When the air bleeding mode is selected, supplying pilot pressure to the first pilot port and the second pilot port;
Shovel according to claim 2. having a proportional valve that controls the pilot pressure;
Shovel according to claim 3. Having a pilot pressure sensor that detects the pilot pressure of the first pilot port and the pilot pressure of the second pilot port,
A shovel according to claim 3 or 4. The control device is
Determining whether the pilot pressures of the first pilot port and the second pilot port are balanced based on the detected value of the pilot pressure sensor;
Shovel according to claim 5. The control device is
If the differential pressure between the pilot pressure of the first pilot port and the pilot pressure of the second pilot port is equal to or greater than a predetermined pressure, it is determined that the balance is not achieved.
Shovel according to claim 6.

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