JP2020002588A - Hydraulic shovel with crane function - Google Patents

Abstract

To provide a hydraulic shovel with a crane function improved in operational stability.SOLUTION: A hydraulic shovel is provide with: a confluence change-over valve 54 merging pressure oil from a second hydraulic pump 52 in an oil passage between a first hydraulic pump 51 and a boom direction change valve 55a; a first electromagnetic valve 59a switchable between a communication state communicating with a confluence pilot oil passage 56c in accordance with boom lifting operation and a cut-off state cutting off the confluence pilot oil passage 56c. An ECU 60 brings the first electromagnetic valve 59a into a communication state in an excavation operation mode and the first electromagnetic valve 59a into the cut-off state in a crane operation mode.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hydraulic excavator with a crane function.

  Patent Literature 1 below discloses a hydraulic shovel that includes a boom speed-up valve that guides pressure oil from a second pump to a circuit that guides pressure oil from a first pump to a boom when a boom raising operation is detected. There is disclosed a technique for stopping the boom acceleration at the time of arm operation by guiding a detection pressure of operation of a direction switching valve to a speed increase release signal passage of a boom speed increasing valve.

  In the following Patent Document 2, when a command pilot pressure for switching to the boom raising side is input to a boom direction switching valve that guides the pressure oil from the first pump to the boom, the same command pilot pressure is input to the junction switching valve. In a hydraulic shovel that joins hydraulic oil from a third pump to a circuit that guides hydraulic oil from a first pump to a boom, when a command pilot pressure for switching to a boom raising side is equal to or lower than a predetermined pressure, a merge switching valve is joined. There is disclosed a technique for improving energy saving during fine operation while ensuring fine operability when driving the boom by not switching to a position.

JP-A-2005-40575 JP 2017-227338 A

  By the way, a hydraulic shovel with a crane function that can perform a suspended load operation (also referred to as a crane operation) by a hook attached to a tip of an arm is known. When the technology of Patent Document 1 is applied to such a hydraulic excavator with a crane function, the speed of the boom is increased as soon as only the arm operation is stopped from the simultaneous operation of the boom and the arm during the work of the suspended load, and the suspended load is balanced. This causes problems such as collapse. Further, in the technique of Patent Document 2, when the boom is finely operated during the hanging load operation, the operability is stable, but as soon as the fine operation of the boom is stopped (the boom raising operation is instructed by the boom raising command pilot pressure). As soon as the boom is operated at a pressure equal to or higher than the predetermined pressure), the boom speed is increased, and the same problem occurs. That is, in a hydraulic excavator with a crane function, the boom speed is increased during the boom raising alone operation, and when the boom raising and the arm excavation are performed simultaneously, the excavation operation is performed such that the boom speed is slower than that during the boom raising alone operation. There is a problem that the operation speed becomes uneven due to the type of the cranes during the crane operation and the operation becomes unstable.

  In view of the above problems, an object of the present invention is to provide a hydraulic excavator with a crane function with improved operation stability.

A hydraulic excavator with a crane function according to the present invention includes a boom rotatably attached to an upper revolving unit, an arm rotatably attached to a tip of the boom, and a pivotally attached to a tip of the arm. A bucket for digging work, a hook for crane work attached to the tip of the arm, and a control unit for controlling switching between a digging work mode using the bucket and a crane working mode using the hook. ,
A boom cylinder for driving the boom, an arm cylinder for driving the arm, a first hydraulic pump for supplying pressure oil to the boom cylinder, a second hydraulic pump for supplying pressure oil to the arm cylinder, A boom direction switching valve for switching the direction of pressure oil supplied to the cylinder and adjusting the flow rate; an arm direction switching valve for switching the direction of pressure oil supplied to the arm cylinder to adjust the flow rate; A merging switching valve provided between a pump and the direction switching valve for the arm, and for merging pressure oil from the second hydraulic pump into an oil passage between the first hydraulic pump and the direction switching valve for the boom; ,
A first pilot oil passage for guiding pilot pressure oil to a boom raising pilot port of the boom directional switching valve in response to a boom raising operation of a boom operating device; and a branching branch from the first pilot oil passage. A first solenoid valve that switches between a second pilot oil passage that guides pilot pressure oil as a merge command to the valve, a communication state that communicates with the second pilot oil passage, and a cutoff state that shuts off the second pilot oil passage. And
The control unit sets the first solenoid valve in a communication state in the excavation operation mode, and sets the first solenoid valve in a shut-off state in the crane operation mode.

In the present invention, a bucket cylinder for driving the bucket, a bucket direction switching valve for switching a direction of pressure oil supplied to the bucket cylinder and adjusting a flow rate, and a bucket for a bucket operated in accordance with a dumping operation of a bucket operating device. A third pilot oil passage for guiding pilot pressure oil to the pilot port on the dump side of the directional switching valve, a communication state in which the third pilot oil passage is communicated, and a cutoff state in which the third pilot oil passage is shut off can be switched. A second solenoid valve;
The control unit may cause the second solenoid valve to be in a communication state in the excavation operation mode, and may shut off the second solenoid valve in the crane operation mode.

  According to the present invention, in the excavation operation mode, by connecting the second pilot oil passage, the junction switching valve uses the hydraulic oil from the second hydraulic pump as the oil between the first hydraulic pump and the boom directional switching valve. Join the road and increase the boom raising speed. On the other hand, in the crane operation mode, by shutting off the second pilot oil passage, the junction switching valve prevents the hydraulic oil from the second hydraulic pump from joining the oil passage between the first hydraulic pump and the boom directional switching valve. Therefore, the speed of raising the boom does not increase. As a result, operational stability can be improved in crane work.

It is a side view showing the hydraulic shovel concerning this embodiment. It is a figure showing the hydraulic circuit of the hydraulic shovel concerning this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Structure of hydraulic excavator]
First, a schematic structure of the excavator 1 will be described with reference to FIG.

  The lower traveling body 2 is driven by receiving power from the engine 42, and causes the hydraulic excavator 1 to travel. The lower traveling body 2 includes a pair of left and right crawlers 21 and 21 and a pair of left and right traveling motors 22L and 22R (the right traveling motor 22R is not shown in FIG. 1). The left and right traveling motors 22L and 22R, which are hydraulic motors, drive the left and right crawlers 21 and 21, respectively, so that the hydraulic excavator 1 can move forward and backward. Further, the lower traveling body 2 is provided with a blade 23 and a blade cylinder 24 which is a hydraulic actuator for rotating the blade 23 in a vertical direction.

  The work machine 3 is driven by receiving power from the engine 42 and performs excavation work such as earth and sand. The work machine 3 includes a boom 31, an arm 32, and a bucket 33, and enables excavation work by independently driving these. The boom 31, the arm 32, and the bucket 33 each correspond to a working unit, and the excavator 1 has a plurality of working units.

  One end of the boom 31 is supported by the front part of the upper swing body 4, and is rotated by a boom cylinder 31a which is movable in a stretchable manner. Further, the arm 32 has one end supported by the other end of the boom 31, and is rotated by an arm cylinder 32a that is movable in a stretchable manner. One end of the bucket 33 is supported by the other end of the arm 32, and the bucket 33 is rotated by a bucket cylinder 33a that is movable in a retractable manner. The boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a correspond to a hydraulic actuator that drives a working unit.

  The bucket 33 is a container-shaped member provided at the tip of the work machine 3 and having a claw for performing an excavation operation. The bucket 33 is rotatably attached to the tip of the arm 32 via a connecting pin 34. Further, the bucket 33 is connected to a bucket cylinder 33a via a link mechanism 35.

  A hook 36 for crane work is attached to the other end (tip) of the arm 32. The hook 36 is a hook-shaped member that performs a crane operation, and is rotatably provided to the link mechanism 35. The hook 36 is rotatably supported about the axis of the link mechanism 35 as a rotation fulcrum. The hook 36 is moved between a deployed state protruding from the bucket 33 shown in FIG. You can change your posture.

  The excavator 1 can switch between an excavation operation mode using the bucket 33 with the hooks 36 stored and a crane operation mode using the hooks 36 with the hooks 36 deployed. The excavation work mode and the crane work mode are selected by an operator using a mode switch not shown.

  The upper swing body 4 is configured to be swingable with respect to the lower traveling body 2 via a swing bearing (not shown). A control section 41, an engine 42, a swivel table 43, a swivel motor 44, and the like are arranged on the upper swing body 4. The upper revolving superstructure 4 revolves via the revolving bearing by the driving force of the revolving motor 44 which is a hydraulic motor. Further, a plurality of hydraulic pumps (not shown in FIG. 1) driven by the engine 42 are disposed on the upper swing body 4. These hydraulic pumps supply pressure oil to the boom cylinder 31a, the arm cylinder 32a, the bucket cylinder 33a, and the like.

  The cockpit 411 is arranged in the control section 41. A pair of work operation levers 412 and 412 are arranged on the left and right sides of the cockpit 411, and a pair of traveling levers 413 and 413 are arranged in front of the cockpit 411. The operator controls the engine 42, the hydraulic motors, the hydraulic actuators, and the like by sitting on the cockpit 411 and operating the work operation levers 412, 412, the travel levers 413, 413, etc., and travels, turns, and works. Etc. can be performed.

[Configuration of hydraulic circuit]
The hydraulic circuit 5 of the excavator 1 will be described with reference to FIG. The hydraulic circuit 5 includes a boom cylinder 31a, an arm cylinder 32a, a bucket cylinder 33a, a left traveling motor 22L, a right traveling motor 22R, a turning motor 44, a first hydraulic pump 51, a second hydraulic pump 52, and a third hydraulic pump. 53 and a merge switching valve 54.

  The first hydraulic pump 51, the second hydraulic pump 52, and the third hydraulic pump 53 are driven by the engine 42 and discharge pressure oil supplied to the hydraulic actuator. The first hydraulic pump 51 supplies pressure oil to mainly the right traveling motor 22R, the boom cylinder 31a, and the bucket cylinder 33a to be driven. The second hydraulic pump 52 is mainly driven by supplying pressure oil to the left traveling motor 22L and the arm cylinder 32a. The third hydraulic pump 53 is mainly driven by supplying pressure oil to the swing motor 44. In FIG. 2, the oil passages of the pressure oil supplied from the first hydraulic pump 51, the second hydraulic pump 52, and the third hydraulic pump 53 are indicated by solid lines.

  The hydraulic circuit 5 includes a pilot pump (not shown). The pilot pump discharges pilot oil as a command input to the merge switching valve 54 and a direction switching valve 55 described later. The pilot pump is driven by the engine 42 and generates pilot pressure in an oil passage by discharging pressure oil. In FIG. 2, the oil passage of the pilot oil supplied from the pilot pump is indicated by a broken line.

  The hydraulic actuators (the boom cylinder 31a, the arm cylinder 32a, the bucket cylinder 33a, the left traveling motor 22L, the right traveling motor 22R, and the turning motor 44) are provided with corresponding direction switching valves 55, respectively. This is a pilot-type directional switching valve capable of switching the direction and flow rate of pressure oil supplied from the first hydraulic pump 51, the second hydraulic pump 52, and the third hydraulic pump 53 to the hydraulic actuator. The direction switching valve 55 can be switched to a plurality of positions by sliding a spool. When the pilot pressure is not applied to any of the two pilot ports of the direction switching valve 55, the direction switching valve 55 is held at the neutral position by the urging force of the spring. When the directional control valve 55 is in the neutral position, the pressure oil is not supplied to the corresponding hydraulic actuator. On the other hand, when the pilot pressure is applied to any of the pilot ports of the direction switching valve 55, the direction switching valve 55 is switched from the neutral position to another position, and the pressure oil is supplied to the corresponding hydraulic actuator.

  In the present embodiment, the boom direction switching valve 55a corresponding to the boom cylinder 31a, the arm direction switching valve 55b corresponding to the arm cylinder 32a, the bucket direction switching valve 55c corresponding to the bucket cylinder 33a, and the left traveling motor 22L A corresponding left traveling direction switching valve 55d, a right traveling direction switching valve 55e corresponding to the right traveling motor 22R, and a turning direction switching valve 55f corresponding to the turning motor 44 are provided. These directional control valves are collectively called control valves. Each of the right traveling direction switching valve 55e, the boom direction switching valve 55a, and the bucket direction switching valve 55c is of an open center type, and the upstream side is connected to the first hydraulic pump 51, and the downstream side is connected to the tank. It is arranged in one center oil passage 51a in tandem. The left direction switching valve 55d and the arm direction switching valve 55b are tandemly arranged in a second center oil passage 52a having an upstream side connected to the second hydraulic pump 52 and a downstream side connected to the tank. . The turning direction switching valve 55f is of an open center type. The upstream side is connected to the third hydraulic pump 53, and the downstream side is arranged in the third center oil passage 53a connected to the second center oil passage 52a. I have.

  The hydraulic circuit 5 includes a merging switching valve 54. The merging switching valve 54 is connected between the second hydraulic pump 52 and the arm direction switching valve 55b, more specifically, the left traveling direction switching valve 55d and the arm. The second direction oil passage 52a is provided between the second direction oil passage 52a and the use direction switching valve 55b. The junction switching valve 54 is a first center oil passage 51a between the first hydraulic pump 51 and the boom direction switching valve 55a, more specifically, a right traveling direction switching valve 55e and a boom direction switching valve 55a. This is a pilot-type directional switching valve capable of joining the pressure oil from the second hydraulic pump 52 to the first center oil passage 51a.

  The junction switching valve 54 can be switched to the position 54X or the position 54Y by sliding the spool. When pilot pressure is applied to the pilot port 541 of the junction switching valve 54, the junction switching valve 54 is switched to the position 54X. When the pilot pressure is applied to the pilot port 542 of the junction switching valve 54, the junction switching valve 54 is switched to the position 54Y. When the pilot pressure is applied to both the pilot port 541 and the pilot port 542 of the junction switching valve 54, or when the pilot pressure is not applied to both the pilot port 541 and the pilot port 542 of the junction switching valve 54, the spring is attached. The merger switching valve 54 is held at the position 54Y by the force.

  When the merging switching valve 54 is at the position 54X, the hydraulic oil discharged from the second hydraulic pump 52 communicates with the first hydraulic pump 51 and the boom direction via the merging oil passage 54a branched from the second center oil passage 52a. The first center oil passage 51a is connected to the switching valve 55a. On the other hand, when the junction switching valve 54 is at the position 54Y, the junction oil passage 54a branched from the second center oil passage 52a is shut off, and the pressure oil discharged from the second hydraulic pump 52 is supplied to the second center oil passage 52a. Is supplied to the arm direction switching valve 55b.

  The hydraulic circuit 5 includes a boom operating device 56, an arm operating device 57, and a bucket operating device 58. The boom operating device 56, the arm operating device 57, and the bucket operating device 58 include a pair of work operation levers 412 and 412.

  The boom operating device 56 has a boom remote control valve 560 for switching the direction and pressure of the pilot pressure oil supplied to the boom direction switching valve 55a. Pressure oil discharged from a pilot pump (not shown) is supplied to the boom remote control valve 560. The boom remote control valve 560 includes a pair of pilot valves 561 and 562 that generate a pilot pressure according to the operation direction and the operation amount of the boom operation device 56. Here, the pilot valve 561 is a pilot valve on the boom raising side, and the pilot valve 562 is a pilot valve on the boom lowering side. The pilot valve 561 is connected to a boom raising side pilot port 551 of the boom direction switching valve 55a via a boom raising pilot oil passage 56a (corresponding to a first pilot oil passage). The pilot valve 562 is connected to a boom lowering-side pilot port 552 of the boom direction switching valve 55a via a boom lowering pilot oil passage 56b. The boom remote control valve 560 supplies pressure oil supplied from the pilot pump to the boom direction switching valve 55a as pilot pressure oil via the boom raising pilot oil passage 56a and the boom lowering pilot oil passage 56b. By operating the boom operating device 56, the boom direction switching valve 55a is switched, and the direction of the pressure oil supplied to the boom cylinder 31a can be switched to adjust the flow rate.

  The boom raising pilot oil passage 56a is branched into a merged pilot oil passage 56c (corresponding to a second pilot oil passage). The joining pilot oil passage 56c is connected to the pilot port 541 of the joining switching valve 54. Thus, the pilot pressure generated in the boom raising pilot oil passage 56a in response to the boom raising operation of the boom operating device 56 is also applied to the pilot port 541 of the merging switching valve 54 via the merging pilot oil passage 56c. The junction switching valve 54 is switched to the position 54X, and the pressure oil discharged from the second hydraulic pump 52 is joined to the first center oil passage 51a via the junction oil passage 54a.

  The merged pilot oil passage 56c is provided with a first solenoid valve 59a. The first solenoid valve 59a can be switched between a communicating state in which the joining pilot oil passage 56c is communicated and a shut-off state in which the joining pilot oil passage 56c is shut off. By sliding the spool, the first solenoid valve 59a can be switched to a communication state in which the joining pilot oil passage 56c is communicated or a blocking state in which the joining pilot oil passage 56c is shut off. When a command from the ECU 60 (described later) is not input to the pilot port of the first solenoid valve 59a, the first solenoid valve 59a is kept in a communicating state by the urging force of the spring. On the other hand, when a command from the ECU 60 is input to the pilot port of the first solenoid valve 59a, the first solenoid valve 59a is switched from the communication state to the cutoff state. By bringing the first solenoid valve 59a into the shut-off state, the junction pilot oil passage 56c is shut off, and no pilot pressure is applied to the pilot port 541 of the junction switching valve 54, so that the junction branched from the second center oil passage 52a. The oil passage 54a is shut off. Therefore, the pressure oil discharged from the second hydraulic pump 52 does not join the first center oil passage 51a between the first hydraulic pump 51 and the boom direction switching valve 55a.

  The arm operating device 57 has an arm remote control valve 570 for switching the direction and pressure of the pilot pressure oil supplied to the arm direction switching valve 55b. Pressure oil discharged from a pilot pump (not shown) is supplied to the arm remote control valve 570. The arm remote control valve 570 includes a pair of pilot valves 571 and 572 that generate a pilot pressure according to the operation direction and the operation amount of the arm operation device 57. Here, the pilot valve 571 is a pilot valve on the excavation side, and the pilot valve 572 is a pilot valve on the dump side. The pilot valve 571 is connected to the pilot port 553 on the digging side of the arm direction switching valve 55b via the arm digging pilot oil passage 57a. The pilot valve 572 is connected to a pilot port 554 on the dump side of the arm direction switching valve 55b via an arm dump pilot oil passage 57b. The arm remote control valve 570 supplies pressure oil supplied from the pilot pump to the arm direction switching valve 55b as pilot pressure oil via the arm excavation pilot oil passage 57a and the arm dump pilot oil passage 57b. By operating the arm operating device 57, the direction switching valve 55b for the arm is switched, and the direction of the pressure oil supplied to the arm cylinder 32a is switched to adjust the flow rate.

  The arm excavation pilot oil passage 57a is branched into a communication pilot oil passage 57c. The communication pilot oil passage 57 c is connected to a pilot port 542 of the merge switching valve 54. Thereby, the pilot pressure generated in the arm excavation pilot oil passage 57a in response to the arm excavation operation of the arm operating device 57 is also applied to the pilot port 542 of the junction switching valve 54 via the communication pilot oil passage 57c. The junction switching valve 54 is switched to the position 54Y, and the pressure oil discharged from the second hydraulic pump 52 is supplied to the arm direction switching valve 55b via the second center oil passage 52a.

  The bucket operating device 58 has a bucket remote control valve 580 for switching the direction and pressure of the pilot pressure oil supplied to the bucket direction switching valve 55c. Pressure oil discharged from a pilot pump (not shown) is supplied to the bucket remote control valve 580. The bucket remote control valve 580 includes a pair of pilot valves 581 and 582 that generate a pilot pressure according to the operation direction and the operation amount of the bucket operation device 58. Here, the pilot valve 581 is a pilot valve on the dump side, and the pilot valve 582 is a pilot valve on the excavation side. The pilot valve 581 is connected to a pilot port 555 on the dump side of the bucket direction switching valve 55c via a bucket dump pilot oil passage 58a (corresponding to a third pilot oil passage). The pilot valve 582 is connected to a pilot port 556 on the excavation side of the bucket direction switching valve 55c via a bucket excavation pilot oil passage 58b. Bucket remote control valve 580 supplies pressure oil supplied from the pilot pump to bucket direction switching valve 55c as pilot pressure oil via bucket dump pilot oil passage 58a and bucket excavation pilot oil passage 58b. By operating the bucket operating device 58, the bucket direction switching valve 55c is switched, and the direction of the pressure oil supplied to the bucket cylinder 33a can be switched to adjust the flow rate.

  The bucket dump pilot oil passage 58a is provided with a second solenoid valve 59b. The second solenoid valve 59b can be switched between a communication state in which the bucket dump pilot oil passage 58a is communicated and a cutoff state in which the bucket dump pilot oil passage 58a is shut off. By sliding the spool, the second solenoid valve 59b can switch between a communication state in which the bucket dump pilot oil passage 58a is communicated and a cut-off state in which the bucket dump pilot oil passage 58a is shut off. When a command from the ECU 60 is not input to the pilot port of the second solenoid valve 59b, the second solenoid valve 59b is kept in communication by the urging force of the spring. On the other hand, when a command from the ECU 60 is input to the pilot port of the second solenoid valve 59b, the second solenoid valve 59b is switched from the communication state to the cutoff state. By setting the second solenoid valve 59b to the shut-off state, the bucket dump pilot oil passage 58a is set to the shut-off state, and no pilot pressure is applied to the pilot port 555 of the bucket direction switching valve 55c. Therefore, the dump operation by the bucket operation device 58 is restricted.

  The hydraulic circuit 5 includes an ECU 60 (corresponding to a control unit) that performs control for switching between the excavation operation mode and the crane operation mode. The ECU 60 can send a command to the first solenoid valve 59a and the second solenoid valve 59b.

[Operation of hydraulic circuit]
First, the operation of the hydraulic circuit 5 in the excavation operation mode will be described. When the excavation work mode is selected by the operator, the ECU 60 does not send a command to the first solenoid valve 59a and the second solenoid valve 59b. As a result, the joining pilot oil passage 56c and the bucket dump pilot oil passage 58a are in a state of communication.

  When the boom raising operation of the boom operating device 56 and the arm excavation operation of the arm operating device 57 are performed at the same time, the pilot pressure generated according to the boom raising operation of the boom operating device 56 changes the boom direction switching valve 55a. And the pilot port 551 of the merge switching valve 54. Further, the pilot pressure generated in response to the arm excavation operation of the arm operating device 57 is applied to the pilot port 553 of the arm direction switching valve 55b and the pilot port 542 of the merging switching valve 54. That is, since the pilot pressure is applied to both the pilot port 541 and the pilot port 542 of the junction switching valve 54, the junction switching valve 54 is held at the position 54Y. Thereby, the pressure oil discharged from the first hydraulic pump 51 is supplied to the boom raising side of the boom cylinder 31a via the boom direction switching valve 55a, and the pressure oil discharged from the second hydraulic pump 52 is supplied to the arm It is supplied to the excavation side of the arm cylinder 32a through the use direction switching valve 55b. As a result, the boom 31 is driven at a boom raising speed corresponding to the boom raising operation of the boom operating device 56, and the arm 32 is driven at an arm digging speed corresponding to the arm digging operation of the arm operating device 57.

  When the arm excavating operation of the arm operating device 57 is not performed and only the boom raising operation of the boom operating device 56 is performed, the pilot pressure generated in accordance with the boom raising operation of the boom operating device 56 is changed to the boom pressure. It is provided to the pilot port 551 of the use direction switching valve 55a and also to the pilot port 541 of the merging switching valve 54. On the other hand, since the arm excavating operation of the arm operating device 57 is not performed, no pilot pressure is applied to the pilot port 542 of the merge switching valve 54. That is, since the pilot pressure is applied only to the pilot port 541 of the junction switching valve 54, the junction switching valve 54 is switched to the position 54X. Thereby, the pressure oil discharged from the second hydraulic pump 52 is combined with the pressure oil discharged from the first hydraulic pump 51 and supplied to the boom raising side of the boom cylinder 31a via the boom direction switching valve 55a. Is done. As a result, at the time of the independent operation of the boom raising, the pressure oil supplied to the boom cylinder 31a via the boom direction switching valve 55a increases, so that the boom raising speed of the boom 31 can be increased.

  Next, the operation of the hydraulic circuit 5 in the crane operation mode will be described. When the crane operation mode is selected by the operator, the ECU 60 switches the first solenoid valve 59a to the shut-off state so that the pressure oil discharged from the second hydraulic pump 52 does not join the first center oil passage 51a. . Thus, in the crane operation mode, the boom raising speed of the boom 31 is not increased even during the single operation of raising the boom. Therefore, even when the simultaneous operation of the boom raising and the arm excavation is changed to the single operation of the boom raising, the boom raising speed is not increased, and the simultaneous operation of the boom raising and the arm excavation is performed from the single operation of the boom raising. Even when the operation is changed to an operation, the boom raising speed is not reduced, so that the operation stability in the crane operation can be improved.

  When the crane operation mode is selected by the operator, the ECU 60 switches the second solenoid valve 59b to the shut-off state, and regulates the dump operation by the bucket operating device 58. Thereby, it is possible to prevent the bucket 33 from dumping and interfering with the hook 36, thereby improving the stability of operation and ensuring safety in the crane operation.

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is shown not only by the description of the embodiment but also by the claims, and further includes meanings equivalent to the claims and all changes within the scope.

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Undercarriage 3 Work implement 4 Upper revolving superstructure 5 Hydraulic circuit 31 Boom 31a Boom cylinder 32 Arm 32a Arm cylinder 33 Bucket 33a Bucket cylinder 36 Hook 51 1st hydraulic pump 52 2nd hydraulic pump 54 Merge switching valve 55a Direction switching valve 55b arm direction switching valve 56 boom operating device 56a boom raising pilot oil passage 56c merging pilot oil passage 57 arm operating device 58a bucket dump pilot oil passage 59a first solenoid valve 59b second solenoid valve 60 ECU

Claims (2)

A boom rotatably attached to the upper swing body, an arm rotatably attached to a tip of the boom, a bucket for excavation work rotatably attached to a tip of the arm, and the arm A hook for crane work attached to the tip of the, and a control unit that performs control to switch between a digging work mode using the bucket and a crane work mode using the hook,
A boom cylinder for driving the boom, an arm cylinder for driving the arm, a first hydraulic pump for supplying pressure oil to the boom cylinder, a second hydraulic pump for supplying pressure oil to the arm cylinder, A boom direction switching valve for switching the direction of pressure oil supplied to the cylinder and adjusting the flow rate; an arm direction switching valve for switching the direction of pressure oil supplied to the arm cylinder to adjust the flow rate; A merging switching valve provided between a pump and the direction switching valve for the arm, and for merging pressure oil from the second hydraulic pump into an oil passage between the first hydraulic pump and the direction switching valve for the boom; ,
A first pilot oil passage for guiding pilot pressure oil to a boom raising pilot port of the boom directional switching valve in response to a boom raising operation of a boom operating device; and a branching branch from the first pilot oil passage. A second pilot oil passage that guides pilot pressure oil as a merge command to the valve; a first solenoid valve that can be switched between a communication state in which the second pilot oil passage is communicated and a cutoff state in which the second pilot oil passage is shut off; And
The hydraulic excavator with a crane function, wherein the control unit sets the first electromagnetic valve in a communication state in the excavation operation mode and sets the first electromagnetic valve in a closed state in the crane operation mode. A bucket cylinder for driving the bucket, a bucket directional switching valve for switching the direction of pressure oil supplied to the bucket cylinder and adjusting a flow rate, and a bucket directional switching valve in response to a dump operation of a bucket operating device. A third solenoid valve that switches between a third pilot oil passage that guides pilot pressure oil to a pilot port on the dump side, a communication state that communicates with the third pilot oil passage, and a cutoff state that shuts off the third pilot oil passage. And
The hydraulic shovel with a crane function according to claim 1, wherein the control unit sets the second electromagnetic valve in a communication state in the excavation operation mode, and sets the second electromagnetic valve in a closed state in the crane operation mode.

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