Excavator

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

[Technical field]

[0001] The present disclosure relates to a shovel. [Background technology]

[0002] A working machine is known that includes a lower traveling body, an upper rotating body that can rotate relative to the lower traveling body, an attachment attached to the upper rotating body, a swing hydraulic motor that rotates the upper rotating body, and a hydraulic actuator that drives the attachment. Patent Document 1 discloses a fluid pressure control device that enables air bleeding from a pilot chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-75341 A Summary of the Invention [Problem to be solved by the invention]

[0004] When an excavator is assembled and hydraulic oil is supplied to the hydraulic circuit, air is mixed into the pilot line, so an air bleeding operation is performed to remove the air from the pilot line.

[0005] Therefore, an object of the present invention is to provide a shovel that improves the workability of air bleeding work. [Means for solving the problem]

[0006] The excavator according to an embodiment of the present invention includes an upper rotating body, a lower traveling body, a directional control valve, A pilot line for supplying hydraulic oil to a pilot port of the directional control valve; A shovel having a control device, the control device comprising: The air bleeder has an air bleed mode for bleed-off the air from the pilot line, and when the air bleed mode is selected, When the directional control valve is in a neutral state, both sides of the spool of the directional control valve The hydraulic oil of the pilot line is supplied to each of the pilot ports provided at supplies. Effect of the Invention

[0007] According to the present invention, a shovel that improves the workability of air bleeding work can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a shovel according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a top view of the excavator of FIG. 1. [Diagram 3] FIG. 2 is a diagram showing a configuration example of a hydraulic system mounted on the excavator shown in FIG. [Figure 4A] FIG. 1 is a diagram of a portion of the hydraulic system for operation of the arm cylinder. [Figure 4B] FIG. 2 is a diagram of a portion of the hydraulic system for the boom cylinder. [Figure 4C] FIG. 2 is a diagram of a portion of the hydraulic system for a bucket cylinder. [Figure 4D] FIG. 2 is a diagram of a portion of a hydraulic system for a swing hydraulic motor. [Diagram 5] 10 is a flowchart illustrating an air bleeding operation. [Figure 6] 4 is an example of a graph showing the relationship between a stroke amount of a spool in a control valve and a pilot pressure. [Figure 7] FIG. 2 is a schematic diagram illustrating an example of a control valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, a shovel 100 as an excavator according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a side view of the shovel 100, and Figure 2 is a top view of the shovel 100.

[0010] In this embodiment, the lower traveling structure 1 of the excavator 100 includes a crawler 1C. The crawler 1C is driven by a traveling hydraulic motor 2M as a traveling actuator mounted on the lower traveling structure 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.

[0011] An upper rotating body 3 is rotatably mounted on the lower traveling body 1 via a rotating mechanism 2. The rotating mechanism 2 is driven by a rotating hydraulic motor 2A serving as a rotating actuator mounted on the upper rotating body 3. However, the rotating actuator may be a rotating motor-generator serving as an electric actuator.

[0012] A boom 4 is attached to the upper rotating body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5 as an end attachment. The boom 4, arm 5, and bucket 6 constitute an attachment AT, which is an example of an attachment. The boom 4 is driven by a boom cylinder 7, the arm 5 is driven by an arm cylinder 8, and the bucket 6 is driven by a bucket cylinder 9. The boom cylinder 7, arm cylinder 8, and bucket cylinder 9 constitute an attachment actuator. In the example shown in Figs. 1 and 2, the bucket 6 is an excavation bucket, but it may be a skeleton bucket or a (gravel removal bucket). The bucket 6 may also be equipped with a bucket tilt mechanism.

[0013] The upper rotating body 3 is provided with a cabin 10 as a driver's cab, and is equipped with a power source such as an engine 11. An operation device 26, a controller 30, an operation method switching device SD, etc. are provided inside the cabin 10. In addition, a spatial recognition device 70, etc. are attached to the upper rotating body 3. For convenience, in this specification, 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.

[0014] The spatial recognition device 70 is configured to recognize an object present in a three-dimensional space around the shovel 100. The spatial recognition device 70 may be configured to calculate a distance from the spatial recognition device 70 or the shovel 100 to the recognized object. The spatial recognition device 70 includes, for example, an ultrasonic sensor, a millimeter wave radar, an imaging device, a LIDAR, a distance image sensor, an infrared sensor, or any combination thereof. The imaging device is, for example, a monocular camera or a stereo camera. In this embodiment, the spatial recognition device 70 includes a forward sensor 70F attached to the front end of the upper surface of the cabin 10, a rear sensor 70B attached to the rear end of the upper surface of the upper rotating body 3, a left sensor 70L attached to the left end of the upper surface of the upper rotating body 3, and a right sensor 70R attached to the right end of the upper surface of the upper rotating body 3. An upward sensor that recognizes an object present in the space above the upper rotating body 3 may be attached to the shovel 100.

[0015] 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 actuator includes at least one of a hydraulic actuator and an electric actuator.

[0016] The operation mode switching device SD is configured to be able to switch the operation mode of the operation lever. For example, the operation mode switching device SD includes a push button switch provided on the right console in the cabin 10, and is configured to be able to switch the operation mode of the operation lever between a first operation mode and a second operation mode each time the push button switch is pressed. For example, the first operation mode is configured such that when the left operation lever 26L (see FIG. 3) is tilted forward, the arm 5 is opened, when the left operation lever 26L is tilted backward, the arm 5 is closed, when the left operation lever 26L is tilted left, a left turn is performed, and when the left operation lever 26L is tilted right, a right turn is performed. The first operation method is configured so that when the right operation lever 26R (see FIG. 3) is tilted forward, the boom 4 is lowered, when the right operation lever 26R is tilted rearward, the boom 4 is raised, when the right operation lever 26R is tilted leftward, the bucket 6 is closed, and when the right operation lever 26R is tilted rightward, the bucket 6 is opened. On the other hand, the second operation method is configured so that when the left operation lever 26L (see FIG. 3) is tilted forward, a right turn is performed, when the left operation lever 26L is tilted rearward, a left turn is performed, when the left operation lever 26L is tilted leftward, the arm 5 is opened, and when the left operation lever 26L is tilted rightward, the arm 5 is closed.

[0017] An operator of the shovel 100 may, for example, select the first operation method when performing excavation work using an excavation bucket, and may select the second operation method when performing gravel removal work using a skeleton bucket (gravel removal bucket).

[0018] The controller 30 is a control device for controlling the shovel 100. In this embodiment, the controller 30 is configured with a computer including a CPU, a volatile storage device, a nonvolatile storage device, and the like. The controller 30 reads out 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 operator in manually operating the shovel 100, and a machine control function that supports the operator in manually operating the shovel 100 or automatically or autonomously operates the shovel 100. The controller 30 may include a contact avoidance function that automatically or autonomously operates or stops the shovel 100 to avoid contact between the shovel 100 and an object present within a monitoring range around the shovel 100. Monitoring of objects around the shovel 100 is performed not only within the monitoring range but also outside the monitoring range.

[0019] Next, a configuration example of a hydraulic system mounted on the shovel 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 shovel 100. In Fig. 3, a mechanical power transmission system, a hydraulic oil line, a pilot line, and an electric control system are indicated by double lines, solid lines, dashed lines, and dotted lines, respectively.

[0020] The hydraulic system of the excavator 100 mainly includes an engine 11, a regulator 13, a main pump 14, a pilot pump 15, a control valve unit 17, an operating device 26, a discharge pressure sensor 28, an operation sensor 29, a controller 30, and the like.

[0021] In FIG. 3, the hydraulic system is configured to circulate hydraulic oil from a main pump 14 driven by an engine 11 through a center bypass line 40 or a parallel line 42 to a hydraulic oil tank.

[0022] The engine 11 is a drive source of the excavator 100. In this embodiment, the engine 11 is, for example, a diesel engine that operates to maintain a predetermined rotation speed. An output shaft of the engine 11 is connected to input shafts of the main pump 14 and the pilot pump 15.

[0023] The main pump 14 is configured to supply hydraulic oil via a hydraulic oil line to the control valve unit 17. In this embodiment, the main pump 14 is a swash plate type variable displacement hydraulic pump.

[0024] 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 swash plate tilt angle of the main pump 14 in response to a control command from the controller 30.

[0025] The pilot pump 15 is an example of a pilot pressure generating device, and is configured to be able to supply hydraulic oil to hydraulic control devices via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be realized by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to various hydraulic control devices via a pilot line, in addition to a function of supplying hydraulic oil to the control valve unit 17 via a hydraulic oil line. In this case, the pilot pump 15 may be omitted.

[0026] The control valve unit 17 is a hydraulic control device that controls the hydraulic system in the excavator 100. In this embodiment, the control valve unit 17 includes control valves 171 to 176. The control valve 175 includes a control valve 175L and a control valve 175R, and the control valve 176 includes a control valve 176L and a control valve 176R. The control valve unit 17 is configured to selectively supply hydraulic oil discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176. The control valves 171 to 176 control, for example, the flow rate of hydraulic oil flowing from the main pump 14 to the hydraulic actuators and the flow rate of hydraulic oil flowing from the hydraulic actuators to a hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, a left traveling hydraulic motor 2ML, a right traveling hydraulic motor 2MR, and a swing hydraulic motor 2A.

[0027] The operating device 26 is configured to allow an operator to operate the actuator. In this embodiment, the operating device 26 includes a hydraulic actuator operating device configured to allow an operator to operate the hydraulic actuator. Specifically, the hydraulic actuator operating device is configured to supply hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via a pilot line. The pressure of the hydraulic oil supplied to each pilot port (pilot pressure) is a pressure according to the operation direction and operation amount of the operating device 26 corresponding to each hydraulic actuator.

[0028] 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.

[0029] The operation sensor 29 is configured to detect the content of an operation of the operation device 26 by an operator. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operation device 26 corresponding to each actuator, and outputs the detected values ​​to the controller 30.

[0030] The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates hydraulic oil to a hydraulic oil tank via a left center bypass line 40L or a left parallel line 42L, and the right main pump 14R circulates hydraulic oil to a hydraulic oil tank via a right center bypass line 40R or a right parallel line 42R.

[0031] The left center bypass line 40L is a hydraulic oil line that passes through control valves 171, 173, 175L, and 176L arranged in the control valve unit 17. The right center bypass line 40R is a hydraulic oil line that passes through control valves 172, 174, 175R, and 176R arranged in the control valve unit 17.

[0032] The control valve 171 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the left traveling hydraulic motor 2ML and to discharge the hydraulic oil discharged by the left traveling hydraulic motor 2ML to the hydraulic oil tank.

[0033] The control valve 172 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the right traveling hydraulic motor 2MR and to discharge the hydraulic oil discharged by the right traveling hydraulic motor 2MR to the hydraulic oil tank.

[0034] The control valve 173 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the swing hydraulic motor 2A and to discharge the hydraulic oil discharged by the swing hydraulic motor 2A to the hydraulic oil tank.

[0035] 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.

[0036] The control valve 175L is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the boom cylinder 7. The control valve 175R is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the boom cylinder 7 and to discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

[0037] The control valve 176L is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the arm cylinder 8 and to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

[0038] The control valve 176R 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 arm cylinder 8 and to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

[0039] The left parallel conduit 42L is a hydraulic oil line that runs parallel to the left center bypass conduit 40L. The left parallel conduit 42L can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the left center bypass conduit 40L is restricted or blocked by any of the control valves 171, 173, and 175L. The right parallel conduit 42R is a hydraulic oil line that runs parallel to the right center bypass conduit 40R. The right parallel conduit 42R can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the right center bypass conduit 40R is restricted or blocked by any of the control valves 172, 174, and 175R.

[0040] 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 swash plate tilt angle of the left main pump 14L according to the discharge pressure of the left main pump 14L. Specifically, the left regulator 13L adjusts the swash plate tilt angle of the left main pump 14L in response to an increase in the discharge pressure of the left main pump 14L, for example, to reduce the discharge amount. The same is true for the right regulator 13R. This is to prevent the absorption power (absorption horsepower) of the main pump 14, which is expressed by the product of the discharge pressure and the discharge amount, from exceeding the output power (output horsepower) of the engine 11.

[0041] 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 traveling lever 26DL and a right traveling lever 26DR.

[0042] The left operating lever 26L is used for the rotation operation and the operation of the arm 5. When the left operating lever 26L is operated in the forward / backward direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 176. When the left operating lever 26L is operated in the left / right direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 173.

[0043] Specifically, when the left operating lever 26L is operated in the arm closing direction, it introduces hydraulic oil to the right pilot port of the control valve 176L and introduces hydraulic oil to the left pilot port of the control valve 176R. When the left operating lever 26L is operated in the arm opening direction, it introduces hydraulic oil to the left pilot port of the control valve 176L and introduces hydraulic oil to the right pilot port of the control valve 176R. When the left operating lever 26L is operated in the left turning direction, it introduces hydraulic oil to the left pilot port of the control valve 173, and when operated in the right turning direction, it introduces hydraulic oil to the right pilot port of the control valve 173.

[0044] In the example shown in FIG. 3, the left operating lever 26L functions as an arm operating lever when operated in the forward / rearward direction, and functions as a turning operating lever when operated in the left / right direction.

[0045] The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever 26R is operated in the forward / backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the amount of lever operation into the pilot port of the control valve 175. When the right operating lever 26R is operated in the left / right direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the amount of lever operation into the pilot port of the control valve 174.

[0046] Specifically, the right operating lever 26R introduces hydraulic oil to the left pilot port of the control valve 175R when operated in the boom lowering direction. Furthermore, the right operating lever 26R introduces hydraulic oil to the right pilot port of the control valve 175L and also introduces hydraulic oil to the left pilot port of the control valve 175R when operated in the boom raising direction. Furthermore, the right operating lever 26R introduces hydraulic oil to the right pilot port of the control valve 174 when operated in the bucket closing direction, and introduces hydraulic oil to the left pilot port of the control valve 174 when operated in the bucket opening direction.

[0047] In the example shown in FIG. 3, the right operating lever 26R functions as a boom operating lever when operated in the forward / rearward direction, and functions as a bucket operating lever when operated in the left / right direction.

[0048] 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 forward / backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 171. The right travel lever 26DR is used to operate the right crawler 1CR. It may be configured to be interlocked with the right travel pedal. When the right travel lever 26DR is operated in the forward / backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 172.

[0049] 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.

[0050] The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the content of the operation of the left operation lever 26L by the operator in the forward / rearward direction, and outputs the detected value to the controller 30. The content of the operation includes, for example, the lever operation direction, the lever operation amount (lever operation angle), etc.

[0051] Similarly, the operation sensor 29LB detects the operation of the left operating lever 26L in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RA detects the operation of the right operating lever 26R in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RB detects the operation of the right operating lever 26R in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DL detects the operation of the left traveling lever 26DL in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DR detects the operation of the right traveling lever 26DR in the forward-backward direction by the operator, and outputs the detected value to the controller 30.

[0052] The controller 30 receives the output of the operation sensor 29, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The controller 30 also receives the output of the control pressure sensor 19 provided upstream of the orifice 18, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The orifice 18 includes a left orifice 18L and a right orifice 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

[0053] The left center bypass pipe 40L is provided with a left throttle 18L between the most downstream control valve 176L and the hydraulic oil tank. Therefore, the flow of hydraulic oil discharged by the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L generates a control pressure for controlling the left regulator 13L. The left control pressure sensor 19L is a sensor for detecting this control pressure, and outputs the detected value to the controller 30. The controller 30 controls the discharge amount of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to this control pressure. The controller 30 reduces the discharge amount of the left main pump 14L as this control pressure increases, and increases the discharge amount of the left main pump 14L as this control pressure decreases. The discharge amount of the right main pump 14R is also controlled in a similar manner.

[0054] Specifically, as shown in FIG. 3, in the case of a standby state in which none of the hydraulic actuators in the excavator 100 are operated, the hydraulic oil discharged by the left main pump 14L passes through the left center bypass pipe 40L and reaches the left throttle 18L. Then, the flow of the hydraulic oil discharged by the left main pump 14L increases the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the allowable minimum discharge amount, suppressing the pressure loss (pumping loss) when the discharged hydraulic oil passes through the left center bypass pipe 40L. On the other hand, when any of the hydraulic actuators is operated, the hydraulic oil discharged by the left main pump 14L flows into the hydraulic actuator to be operated through the control valve corresponding to the hydraulic actuator to be operated. Then, the flow of the hydraulic oil discharged by the left main pump 14L reduces or eliminates the amount of hydraulic oil reaching the left throttle 18L, lowering the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 increases the discharge rate of the left main pump 14L to circulate sufficient hydraulic oil to the hydraulic actuator to be operated, ensuring the drive of the hydraulic actuator to be operated. The controller 30 also controls the discharge rate of the right main pump 14R in a similar manner.

[0055] With the above-described configuration, the hydraulic system of Fig. 3 can suppress unnecessary energy consumption in the main pump 14 in a standby state. The unnecessary energy consumption includes pumping loss caused in the center bypass pipe 40 by the hydraulic oil discharged from the main pump 14. Furthermore, when operating a hydraulic actuator, the hydraulic system of Fig. 3 can reliably supply necessary and sufficient hydraulic oil from the main pump 14 to the hydraulic actuator to be operated.

[0056] In addition, a boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are attached to the boom cylinder 7. An arm rod pressure sensor S8R and an arm bottom pressure sensor S8B are attached to the arm cylinder 8. 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, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B are collectively referred to as "cylinder pressure sensors." In addition, a left swing pressure sensor S10L and a right swing pressure sensor S10R are attached to the swing hydraulic motor 2A.

[0057] The boom rod pressure sensor S7R detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom rod pressure"), and the boom bottom pressure sensor S7B detects the pressure in the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom bottom pressure"). The arm rod pressure sensor S8R detects the pressure in the rod side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm rod pressure"), and the arm bottom pressure sensor S8B detects the pressure in the bottom side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm bottom pressure"). The bucket rod pressure sensor S9R detects the pressure in the rod side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket rod pressure"), and the bucket bottom pressure sensor S9B detects the pressure in the bottom side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket bottom pressure"). The left swing pressure sensor S10L detects the pressure of the hydraulic oil in the left port of the swing hydraulic motor 2A. The right swing pressure sensor S10R detects the pressure of the hydraulic oil in the right port of the swing hydraulic motor 2A. The values ​​detected by each sensor are transmitted to the controller 30 .

[0058] Next, a configuration for the controller 30 to operate the actuators by the machine control function will be described with reference to Fig. 4A to Fig. 4D. Fig. 4A to Fig. 4D are diagrams showing parts of the hydraulic system. Specifically, Fig. 4A is a diagram showing the hydraulic system part related to the operation of the arm cylinder 8, and Fig. 4B is a diagram showing the hydraulic system part related to the operation of the boom cylinder 7. Fig. 4C is a diagram showing the hydraulic system part related to the operation of the bucket cylinder 9, and Fig. 4D is a diagram showing the hydraulic system part related to the operation of the swing hydraulic motor 2A.

[0059] 4A to 4D, the hydraulic system includes a proportional valve 31. The proportional valve 31 includes proportional valves 31AL to 31DL and 31AR to 31DR.

[0060] The proportional valve 31 functions as a control valve for machine control. The proportional valve 31 is disposed in a pipe connecting the pilot pump 15 and a pilot port of a corresponding control valve in the control valve unit 17, and is configured to be able to change the flow passage area of ​​the pipe. In this embodiment, the proportional valve 31 operates in response to a control command output by the controller 30. Therefore, the controller 30 can 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 proportional valve 31, regardless of the operation of the operating device 26 by the operator. Then, the controller 30 can apply the pilot pressure generated by the proportional valve 31 to the pilot port of the corresponding control valve.

[0061] With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a specific operating device 26 even when no operation is being performed on that specific operating device 26. Furthermore, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to that specific operating device 26 even when an operation is being performed on that specific operating device 26.

[0062] For example, as shown in FIG. 4A, the left operating lever 26L is used to operate the arm 5. Specifically, the left operating lever 26L uses hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the forward / rearward direction to the pilot port of the control valve 176. More specifically, when the left operating lever 26L is operated in the arm closing direction (rearward direction), the left operating lever 26L applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in the arm opening direction (forward direction), the left operating lever 26L applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

[0063] The left operation lever 26L is provided with a switch NS. In this embodiment, the switch NS is a push button switch provided at the tip of the left operation lever 26L. The operator can operate the left operation lever 26L while pressing the switch NS. The switch NS may be provided on the right operation lever 26R or at another position in the cabin 10.

[0064] The operation sensor 29LA detects the content of the operation of the left operation lever 26L in the forward / rearward direction by the operator, and outputs the detected value to the controller 30.

[0065] The proportional valve 31AL operates in response to a control command (current command) output by the controller 30. Then, it adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL. The proportional valve 31AR operates in response to a control command (current command) output by the controller 30. Then, it adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR. 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.

[0066] A pilot pressure sensor 32AL for detecting pilot pressure is provided in 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). A pilot pressure sensor 32AR for detecting pilot pressure is provided in 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). Values ​​detected by each of the pilot pressure sensors 32AL and 32AR are transmitted to the controller 30.

[0067] With this configuration, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL in response to the arm closing operation by the operator. Also, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL, regardless of the arm closing operation by the operator. That is, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or regardless of the arm closing operation by the operator.

[0068] Furthermore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR in response to the arm opening operation by the operator. Furthermore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR, regardless of the arm opening operation by the operator. That is, the controller 30 can open the arm 5 in response to the arm opening operation by the operator or regardless of the arm opening operation by the operator.

[0069] Furthermore, with this configuration, even if the operator is performing an arm closing operation, the controller 30 can, if necessary, reduce the pilot pressure acting on the closing side pilot ports of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) to forcibly stop the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

[0070] Alternatively, even if the operator is performing an arm closing operation, the controller 30 may control the proportional valve 31AR as necessary to increase the pilot pressure acting on the opening 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) that is opposite the closing pilot port of the control valve 176, and forcibly return the control valve 176 to the neutral position, thereby forcibly stopping the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

[0071] 4B to 4D, the same applies to the case where the operation of the boom 4 is forcibly stopped when the operator is performing a boom-raising or boom-lowering operation, the case where the operation of the bucket 6 is forcibly stopped when the operator is performing a bucket-closing or bucket-opening operation, and the case where the rotation operation of the upper rotating body 3 is forcibly stopped when the operator is performing a rotation operation. The same applies to the case where the traveling operation of the lower traveling body 1 is forcibly stopped when the operator is performing a traveling operation.

[0072] 4B, the right operating lever 26R is used to operate the boom 4. Specifically, the right operating lever 26R uses hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the forward / rearward direction to the pilot port of the control valve 175. More specifically, when the right operating lever 26R is operated in the boom-up direction (rearward), it applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the boom-down direction (forward), it applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R.

[0073] The operation sensor 29RA detects the content of the operation of the right operating lever 26R in the forward / rearward direction by the operator, and outputs the detected value to the controller 30.

[0074] The proportional valve 31BL operates in response to a control command (current command) output by the controller 30. The proportional valve 31BL adjusts the pilot pressure by the 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 in response to a control command (current command) output by the controller 30. The proportional valve 31BR adjusts the pilot pressure by the 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. The proportional valve 31BR can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position.

[0075] A pilot pressure sensor 32BL for detecting pilot pressure is provided in a pilot line connecting 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 in 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). Values ​​detected by the pilot pressure sensors 32BL and 32BR are transmitted to the controller 30.

[0076] With this configuration, controller 30 can supply hydraulic oil discharged from pilot pump 15 to the left pilot port of control valve 175R via proportional valve 31BL in response to a boom-raising operation by the operator. Also, controller 30 can supply hydraulic oil discharged from pilot pump 15 to the left pilot port of control valve 175R via proportional valve 31BL, regardless of a boom-raising operation by the operator. In other words, controller 30 can raise boom 4 in response to a boom-raising operation by the operator or regardless of a boom-raising operation by the operator.

[0077] Furthermore, the controller 30 can supply the hydraulic oil discharged by 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. Furthermore, the controller 30 can supply the hydraulic oil discharged by 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. In other words, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator or regardless of the boom lowering operation by the operator.

[0078] 4B, the configuration in which the controller 30 controls the proportional valves 31BL, 31BR and supplies the pilot pressure to the control valve 175R has been described. Similarly, the controller 30 controls a proportional valve (not shown) and supplies the pilot pressure to the control valve 175L.

[0079] 4C, the right operating lever 26R is also used to operate the bucket 6. Specifically, the right operating lever 26R utilizes hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the left or right direction to the pilot port of the control valve 174. More specifically, when the right operating lever 26R is operated in the bucket closing direction (left direction), it applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 174. Also, when the right operating lever 26R is operated in the bucket opening direction (right direction), it applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 174.

[0080] The operation sensor 29RB detects the content of the operation of the right operating lever 26R in the left or right direction by the operator, and outputs the detected value to the controller 30.

[0081] The proportional valve 31CL operates in response to a control command (current command) output by the controller 30. The proportional valve 31CR adjusts the pilot pressure by the 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 in response to a control command (current command) output by the controller 30. The proportional valve 31CR adjusts the pilot pressure by the 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.

[0082] A pilot pressure sensor 32CL for detecting pilot pressure is provided in a pilot line connecting 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, 32CR are transmitted to the controller 30.

[0083] With this configuration, controller 30 can supply the hydraulic oil discharged by pilot pump 15 to the left pilot port of control valve 174 via proportional valve 31CL in response to a bucket closing operation by the operator. Moreover, controller 30 can supply the hydraulic oil discharged by pilot pump 15 to the left pilot port of control valve 174 via proportional valve 31CL, regardless of a bucket closing operation by the operator. In other words, controller 30 can close bucket 6 in response to a bucket closing operation by the operator or regardless of a bucket closing operation by the operator.

[0084] Furthermore, in response to a bucket opening operation by the operator, controller 30 can supply the hydraulic oil discharged by pilot pump 15 to the right pilot port of control valve 174 via proportional valve 31CR. Furthermore, regardless of a bucket opening operation by the operator, controller 30 can supply the hydraulic oil discharged by pilot pump 15 to the right pilot port of control valve 174 via proportional valve 31CR. In other words, controller 30 can open bucket 6 in response to a bucket opening operation by the operator or regardless of a bucket opening operation by the operator.

[0085] 4D, the left operation lever 26L is also used to operate the turning mechanism 2. Specifically, the left operation lever 26L uses hydraulic oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the left-right direction to the pilot port of the control valve 173. More specifically, when the left operation lever 26L is operated in the left turning direction (left direction), the left operation lever 26L applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 173. Also, when the left operation lever 26L is operated in the right turning direction (right direction), the left operation lever 26L applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 173.

[0086] The operation sensor 29LB detects the content of the operation of the left operation lever 26L in the left or right direction by the operator, and outputs the detected value to the controller 30.

[0087] The proportional valve 31DL operates in response to a control command (current command) output by the controller 30. The proportional valve 31DL adjusts the pilot pressure by the 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 in response to a control command (current command) output by the controller 30. The proportional valve 31DR adjusts the pilot pressure by the 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.

[0088] A pilot pressure sensor 32DL that detects the 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 that detects the pilot pressure is provided in a pilot line that connects the proportional valve 31DR and the other port of the control valve 173 (the right port of the control valve 173). Values ​​detected by the pilot pressure sensors 32DL and 32DR are transmitted to the controller 30.

[0089] With this configuration, 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 in response to a left turning operation by the operator. Moreover, 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 rotate the turning mechanism 2 left in response to a left turning operation by the operator or regardless of the left turning operation by the operator.

[0090] Furthermore, 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 in response to a right turning operation by the operator. Furthermore, 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 a right turning operation by the operator. That is, the controller 30 can rotate the turning mechanism 2 to the right in response to a right turning operation by the operator or regardless of a right turning operation by the operator.

[0091] The excavator 100 may be configured to automatically move the lower traveling structure 1 forward and backward. In this case, the hydraulic system portion related to the operation of the left traveling hydraulic motor 2ML and the hydraulic system portion related to the operation of the right traveling hydraulic motor 2MR may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7, etc.

[0092] Although the description has been given of an electric control lever as a form of the operation device 26, a hydraulic operation lever may be adopted instead of the electric operation 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, a solenoid valve may be disposed between the operation device 26 as a hydraulic operation lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electric signal from the controller 30. With this configuration, when manual operation is performed using the operation device 26 as a hydraulic operation lever, the operation device 26 can move each control valve by increasing or decreasing the pilot pressure in response to the lever operation amount. Also, each control valve may be configured as an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electric signal from the controller 30 corresponding to the lever operation amount of the electric operation lever.

[0093] Next, the air bleeding operation of the pilot line of the excavator 100 will be described with reference to Fig. 5. Fig. 5 is a flowchart explaining the air bleeding operation. In the following explanation, the 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.

[0094] In step S101, the controller 30 determines whether or not the air bleeding mode has been selected. For example, the excavator 100 is provided with 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 has not been selected (S101: No), the processing of the controller 30 repeats step S101. If the air bleeding mode has been selected (S101: Yes), the processing of the controller 30 proceeds to step S102.

[0095] In step S102, the controller 30 controls the proportional valves 31DL, 31DR to supply pilot pressure to both ports (left pilot port, right pilot port) of the control valve 173. Here, the controller 30 controls the proportional valves 31DL, 31DR so that the pilot pressures supplied to both ports of the control valve 173 are equal to or higher than a predetermined pressure.

[0096] In step S103, controller 30 detects the pilot pressure of the left pilot port of control valve 173 with pilot pressure sensor 32DL, and detects the pilot pressure of the right pilot port of control valve 173 with pilot pressure sensor 32DR.

[0097] In step S104, the controller 30 determines whether or not 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 a predetermined threshold value. 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 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 value (S104·Yes), the process of the controller 30 proceeds to step S106.

[0098] Here, the relationship between the pilot pressure and the spool stroke amount in the control valves 171 to 176 will be described with reference to Fig. 6. Fig. 6 is an example of a graph showing the relationship between the spool stroke amount and the pilot pressure in the control valves 171 to 176. In Fig. 6, the horizontal axis represents the spool stroke amount, and the vertical axis represents the pilot pressure.

[0099] As shown in Fig. 6, when the pilot pressure is equal to or lower than a predetermined preset pressure PVmin (e.g., 0.4 MPa), the stroke amount of the spool is zero (neutral position). When the pilot pressure exceeds the predetermined preset pressure PVmin, the stroke amount of the spool increases as the pilot pressure increases. When the pilot pressure is equal to a predetermined maximum pilot pressure PVmax, the stroke amount of the spool is maximum.

[0100] In this way, when 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 a predetermined threshold value (for example, a value equal to or lower than the preset pressure PVmin), the spool of the control valve 173 maintains the neutral position. That is, the hydraulic oil supplied from the main pump 14 is not supplied to the swing hydraulic motor 2A, and the swing hydraulic motor 2A does not rotate.

[0101] In other words, the controller 30 determines whether or not there is a balance 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. Furthermore, the controller 30 determines that there is no balance when the pressure difference 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 equal to or greater than a predetermined pressure.

[0102] In step S105, the controller 30 controls the proportional valves 31DL, 31DR to correctively control the pilot pressures supplied to both ports of the control valve 173. For example, the other pilot pressure may be controlled to match the higher or lower pilot pressure. In other words, when the controller 30 determines that 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 are not balanced, the controller 30 controls the proportional valves 31DL, 31DR to balance them. Then, the process of the controller 30 proceeds to step S106.

[0103] In step S106, the controller 30 determines whether or not a predetermined time has elapsed 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. If the predetermined time has elapsed (S106: Yes), the process of the controller 30 returns to step S103.

[0104] In step S107, the controller 30 closes the proportional valves 31DL and 31DR, and then the controller 30 ends the process of the air bleeding mode.

[0105] FIG. 7 is a schematic diagram illustrating an example of the control valve 173. As shown in FIG.

[0106] The center bypass passage 701 is connected to the center bypass pipeline 40 (see FIG. 3). The parallel passage 702 is connected to the parallel pipeline 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). The tank port 705 is connected to a hydraulic oil tank. A check valve 707 is provided in the bridge passage 706.

[0107] The left pilot port 708 is connected to the output of the proportional valve 31DL (see FIG. 4D) and the right pilot port 709 is connected to the output of the proportional valve 31DR (see FIG. 4D).

[0108] Spool 710 is configured to be movable to the right by pilot pressure supplied to left pilot port 708. Spool 710 is also configured to be movable to the left by pilot pressure supplied to right pilot port 709. Biasing portion 711 biases spool 710 so as to return to the neutral position.

[0109] When pilot pressure is supplied from the left pilot port 708 and the spool 710 moves to the right, the notch of the spool 710 communicates between the bridge passage 706 and the cylinder port 703. The notch of the spool 710 also communicates between the cylinder port 704 and the right tank port 705. As a result, the hydraulic oil flows from the parallel passage 702 through the bridge passage 706, through the notch of the spool 710 that communicates between the bridge passage 706 and the cylinder port 703, and into the cylinder port 703. The hydraulic oil also flows from the cylinder port 704 through the notch of the spool 710 that communicates between the cylinder port 704 and the right tank port 705, and into the right tank port 705.

[0110] When pilot pressure is supplied from the right pilot port 709 and the spool 710 moves to the left, the notch of the spool 710 communicates between the bridge passage 706 and the cylinder port 704. The notch of the spool 710 also communicates between the cylinder port 703 and the left tank port 705. As a result, the hydraulic oil flows from the parallel passage 702 through the bridge passage 706, through the notch of the spool 710 that communicates between the bridge passage 706 and the cylinder port 704, and into the cylinder port 704. The hydraulic oil also flows from the cylinder port 703 through the notch of the spool 710 that communicates between the cylinder port 703 and the left tank port 705, and into the left tank port 705.

[0111] Here, as shown in step S102, pilot pressures equal to or greater than a predetermined pressure are supplied to the left pilot port 708 and the right pilot port 709. This allows the spool 710 to be maintained in the neutral position.

[0112] Also, as shown in step S106, a state in which pilot pressures equal to or greater than a predetermined pressure are supplied to the left and right pilot ports is maintained for a predetermined time. Thus, by supplying pilot pressure equal to or greater than a predetermined pressure to left pilot port 708, air in the pilot line passes through the gap in spool 710 and is discharged to tank port 705 (see dashed arrow). Similarly, by supplying pilot pressure equal to or greater than a predetermined pressure to right pilot port 709, air in the pilot line passes through the gap in spool 710 and is discharged to tank port 705 (see dashed arrow).

[0113] As described above, according to the excavator 100 of this embodiment, the air bleeding operation of the pilot line can be performed. Moreover, since the spool of the control valve 173 can be kept in 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. This makes it possible to reduce the work space required for the air bleeding operation. Moreover, since the air bleeding operation of the pilot lines on the left and right sides of the control valve 173 can be performed simultaneously, the work time can be shortened.

[0114] Although the air bleeding of 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 thereto and can be applied to the air bleeding work of the pilot lines related to the control valves of other hydraulic actuators. That is, the same can be applied to the pilot line related to the control valve 175 of the boom cylinder 7, the pilot line related to the control valve 176 of the arm cylinder 8, the pilot line related to the control valve 174 of the bucket cylinder 9, the pilot line related to the control valve 171 of the left traveling hydraulic motor 2ML, and the pilot line related to the control valve 172 of the right traveling hydraulic motor 2MR. In addition, the air bleeding work can be performed simultaneously for the left and right pilot lines of the multiple control valves 171 to 176, so that the work time can be shortened. In addition, the air bleeding work can be performed without operating the hydraulic actuator. [Explanation of symbols]

[0115] 100 Shovel 1 Undercarriage 2A Swing Hydraulic Motor (Hydraulic Actuator) 2M Travel 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 valves (directional control valves) 30 Controller (control device) 31 Proportional valve 32 Pilot pressure sensor

Claims

1. An upper rotating body; A lower running body; A directional control valve; a pilot line for supplying hydraulic oil to a pilot port of the directional control valve; A shovel having a control device, The control device includes: An air bleeding mode for bleeding the air from the pilot line, When the air bleeding mode is selected, the directional control valve is in a neutral state and hydraulic oil in the pilot line is supplied to each of the pilot ports provided on both sides of the spool of the directional control valve. Shovel.

2. When the air bleeding mode is selected, The pilot pressure of the hydraulic oil supplied to the pilot port provided on one side of the spool and the pilot pressure of the hydraulic oil supplied to the pilot port provided on the other side of the spool are the same pressure. The shovel according to claim 1.

3. the directional control valve has a first pilot port provided on one side of the spool and a second pilot port provided on the other side of the spool, The control device includes: When the air bleeding mode is selected, the same pilot pressure is supplied to the first pilot port and the second pilot port. The shovel according to claim 2.

4. The pilot line, a first pilot line that supplies hydraulic oil to the first pilot port; a second pilot line that supplies hydraulic oil to the second pilot port, a first proportional valve provided in the first pilot line and configured to control a pilot pressure of the first pilot port; a second proportional valve provided in the second pilot line and controlling the pilot pressure of the second pilot port; The shovel according to claim 3.

5. A first pilot pressure sensor that detects a pilot pressure of the first pilot port; A second pilot pressure sensor that detects the pilot pressure of the second pilot port. The shovel according to claim 3 or 4.

6. The control device includes: Based on detection values ​​of the first pilot pressure sensor and the second pilot pressure sensor, determining whether the pilot pressures of the first pilot port and the second pilot port are balanced; The shovel according to claim 5.

7. The control device includes: When a 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. The shovel according to claim 6.

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