JP2006090074A - Hydraulic driving device of working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic driving device capable of accelerating an action speed of a different working member in the case a combined operation of a boom lowering operation and the different member's operation is carried out by making good use of a pressure oil discharged from bottom rooms of cylinders for the boom in the combined operation of the boom included in the same working machine and the different working member. <P>SOLUTION: The hydraulic driving device of the working machine is equipped with a pipe line 30 connecting the bottom rooms 8a and 9a of the first and second boom cylinders 8 and 9 driving the boom to the bottom room 10a of an arm cylinder 10 driving the arm 6 (the different working member), an arm opening/closing means 28 including a flow controlling valve 31 capable of opening and closing the pipe line 30 and a controller 27 controlling the arm opening and closing means 28 so as to open the flow controlling valve 31 when a boom operating signal A commanding the contraction of the first and second boom cylinders 8 and 9 and an arm operating signal B commanding the expansion of the arm cylinder 10 are simultaneously inputted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is provided in a working machine having a working machine including a boom and a working member different from the boom, and a boom cylinder for driving the boom and another working member cylinder for driving another working member. The present invention relates to a hydraulic drive device for a work machine that drives the machine.

  As a conventional hydraulic drive device for a work machine, for example, there is a conventional technique disclosed in Patent Document 1. This prior art is provided in a backhoe. The backhoe includes a work machine in which a plurality of work members including a boom, that is, a boom, an arm, and a bucket are connected.

  The above-described prior art is different from the hydraulic cylinder that drives the boom, that is, the first and second boom cylinders, and the working member other than the boom, for example, the hydraulic cylinder that drives the arm, that is, the arm cylinder, and the boom. Working members, for example, hydraulic cylinders that drive buckets, that is, bucket cylinders, and hydraulic pumps that discharge pressure oil supplied to each of these hydraulic cylinders, that is, first and second main pumps.

  The prior art also includes first and second boom directional control valves for controlling the flow of pressure oil supplied from the first and second main pumps to the first and second boom cylinders, and the first and second main pumps. First and second directional control valves for controlling the pressure oil supplied from the pump to the arm cylinder, and a first for controlling the flow of pressure oil supplied from the first and second main pumps to the bucket cylinder. And a second bucket direction switching valve.

  In addition, the above-described prior art includes a boom operation device that commands the operation of the boom cylinder by tilting the operation lever, and an arm that commands the operation of the arm cylinder and the bucket cylinder by tilting the operation lever. A bucket operating device is provided.

  The conventional technology configured as described above operates as follows (1) to (4).

(1) Driving the boom When the operator operates the boom operating device to command extension of the boom cylinder, the pressure oil discharged from the first main pump is first and first via the first boom direction switching valve. The pressure oil supplied to the bottom chamber of the second boom cylinder and discharged from the second main pump is supplied to the bottom chambers of the first and second boom cylinders via the second boom direction switching valve. The pressure oil in the rod chambers of the first and second boom cylinders is discharged to the hydraulic oil tank via the first and second boom direction switching valves. As a result, the boom cylinder contracts, and the boom rotates upward.

  When the operator operates the boom operating device to command the boom cylinder to contract, the pressure oil discharged from the first main pump is supplied to the rods of the first and second boom cylinders via the first boom direction switching valve. The pressure oil supplied to the chamber and discharged from the second main pump is supplied to the rod chambers of the first and second boom cylinders via the second boom direction switching valve. The pressure oil in the bottom chambers of the first and second boom cylinders is discharged to the hydraulic oil tank via the first and second boom direction switching valves. As a result, the boom cylinder contracts, and the boom rotates downward. That is, a boom lowering operation is performed.

(2) Driving the arm When the operator operates the arm / bucket operating device to command extension of the arm cylinder, the pressure oil discharged from the first main pump is supplied to the arm via the first arm direction switching valve. The pressure oil supplied to the bottom chamber of the cylinder and discharged from the second main pump is supplied to the bottom chamber of the arm cylinder via the second arm direction switching valve. The pressure oil in the rod chamber of the arm cylinder is discharged to the hydraulic oil tank via the first and second arm direction switching valves. As a result, the arm cylinder is extended, and the arm rotates in a direction in which its tip end approaches the work machine body.

  When the operator operates the arm / bucket operating device to command the contraction of the arm cylinder, the pressure oil discharged from the first main pump is supplied to the rod chamber of the arm cylinder via the first arm direction switching valve. The pressure oil discharged from the second main pump is supplied to the rod chamber of the arm cylinder via the second arm direction switching valve. The pressure oil in the bottom chamber of the arm cylinder is discharged to the hydraulic oil tank via the first and second arm direction switching valves. As a result, the cylinder for the arm contracts, and the arm rotates in a direction in which the tip of the arm separates from the work machine main body.

(3) Driving the bucket When the operator operates the arm / bucket operating device to command extension of the bucket cylinder, the pressure oil discharged from the first main pump is supplied to the bucket via the first bucket direction switching valve. The pressure oil supplied to the bottom chamber of the cylinder and discharged from the second main pump is supplied to the bottom chamber of the bucket cylinder via the second bucket direction switching valve. Further, the pressure oil in the rod chamber of the bucket cylinder is discharged to the hydraulic oil tank via the first and second bucket direction switching valves. As a result, the bucket cylinder extends, and the bucket rotates in a direction in which its tip end approaches the work machine body.

  When an operator operates the arm / bucket operating device to command the contraction of the bucket cylinder, the pressure oil discharged from the first main pump is supplied to the rod chamber of the bucket cylinder via the first bucket direction switching valve. Then, the pressure oil discharged from the second main pump is supplied to the rod chamber of the bucket cylinder through the second bucket direction switching valve. The pressure oil in the bottom chamber of the bucket cylinder is discharged to the hydraulic oil tank via the first and second bucket direction switching valves. As a result, the bucket cylinder contracts, and the bucket rotates in a direction in which its tip end is separated from the work machine body.

(4) Combined operation When the operator commands at least two operations of the boom cylinder, the arm cylinder, and the bucket cylinder by simultaneously operating at least two of the boom operation device, the arm operation device, and the bucket operation device, At least two of the operations described in “(1) to (3)” are performed in parallel. At this time, the pressure oil discharged from the first and second main pumps is distributed to the operating hydraulic cylinder.
JP-A-9-328784 (FIG. 9)

  The above-described hydraulic drive device for a work machine can drive the work machine without any trouble even when the work is performed by a complex operation. By the way, conventionally, in order to improve the work efficiency, there has been a demand for an increase in the operation speed of the work implement.

  As measures to realize this demand, supply to each work member cylinder at the time of compound operation by increasing the number of main pumps and directional control valves or adopting a main pump with higher discharge flow rate according to the specifications. It is conceivable to increase the flow rate of pressure oil. However, with this measure, since the hydraulic drive device becomes large, it is difficult to install such a hydraulic drive device in a limited space of the work machine.

  Therefore, the present inventor, as pressure oil replacing pressure oil discharged from the main pump, pressure oil discharged from the boom cylinder that contracts due to the weight of the work implement, that is, pressure discharged from the bottom chamber of the boom cylinder. Focused on oil.

  The present invention has been made in consideration of the above-described actual situation, and an object of the present invention is a combined operation of a boom and another work member included in the same work machine, in which a boom lowering operation and another work member are used. An object of the present invention is to provide a hydraulic drive device capable of increasing the operating speed of another work member when performing a combined operation with the operation by utilizing the pressure oil discharged from the bottom chamber of the boom cylinder.

[1] In order to achieve the above-mentioned object, the present invention is provided in a work machine having a boom and a work machine including a work member different from the boom, and a boom cylinder for driving the boom; Another working member cylinder that drives another working member, a main pump that discharges pressure oil supplied to the boom cylinder and another working member cylinder, and a boom operation that commands the operation of the boom cylinder A flow of pressure oil supplied from the main pump to the boom cylinder in response to a command from the apparatus, another work member operation device that commands the operation of the other work member cylinder, and the boom operation device And a flow of pressure oil supplied from the main pump to the other work member cylinder in response to a command from the boom direction switching valve and the other work member operation device. In the hydraulic drive device for a work machine including the working member direction switching valve, a pipe line connecting the bottom chamber of the boom cylinder and one of the bottom chamber and the rod chamber of the other working member cylinder The boom cylinder is instructed to be contracted by an opening / closing means including an opening / closing valve provided on the pipeline and capable of opening and closing the pipeline, and a boom operating device that commands the operation of the boom cylinder. And a valve control means for controlling the opening and closing means so that the opening and closing valve is opened when the operation of the other working member cylinder is commanded by the other working member operating device. It is characterized by.

  In the present invention configured as described above, when the operator operates the boom operating device to command the boom cylinder to contract, the pressure oil discharged from the main pump is supplied to the boom cylinder rod via the boom direction switching valve. Then, the pressure oil in the bottom chamber of the boom cylinder is discharged to the hydraulic oil tank via the boom direction switching valve, and the boom cylinder is contracted. Thereby, the boom is rotated downward, that is, the boom is lowered. Further, when the operator operates another work member operation device to command the operation of another work member cylinder, the pressure oil discharged from the main pump is transferred to another work via another work member direction switching valve. Supply to either the bottom chamber or the rod chamber of the member cylinder to operate another working member cylinder.

  In particular, the present invention provides a valve control when the boom operating device is instructed to contract the boom cylinder and the other working member operating device is instructed to operate another working member cylinder. The opening / closing valve is opened by controlling the opening / closing means. As a result, the pressure oil discharged from the bottom chamber of the boom cylinder as the boom cylinder contracts due to the weight of the work implement is supplied to one of the bottom chamber and the rod chamber of another working member cylinder. As a result, when a boom and another work member included in the same work machine are combined, and the boom lowering operation and another work member are combined, another work member cylinder is driven. The flow rate of pressurized oil can be increased. That is, the operating speed of another work member can be increased by utilizing the pressure oil discharged from the bottom chamber of the boom cylinder.

[2] The present invention provides the first operation signal output unit that outputs an electric signal corresponding to the operation of the boom operation device and the operation of the other work member operation device according to the invention described in [1]. A second operation signal output unit that outputs an electric signal to be operated, wherein the on-off valve is a valve that is controlled in response to a control signal that is an electric signal, and the valve control means includes the first and second operations. Determination means for determining whether or not the boom cylinder contraction is instructed and the operation of the other work member cylinder is instructed based on an electric signal output from the signal output unit. When the determination means determines that the boom cylinder contraction is instructed and the operation of the other working member cylinder is instructed, the on-off valve is opened. Opening and closing means And having a control means for outputting a control signal for controlling.

  In the present invention configured as described above, when the operator operates the boom operation device, the first operation signal output unit outputs an electrical signal corresponding to the operation, and when the operator operates another work member operation device, The second operation signal output unit outputs an electrical signal corresponding to the operation.

  Accordingly, the determination unit of the valve control means instructs the contraction of the boom cylinder based on the electric signal output from the first operation signal output unit and the electric signal output from the second operation signal output unit. It is determined whether or not the operation of another working member cylinder is instructed. When the determination result is a determination result indicating that the boom cylinder contraction is instructed and the operation of another work member cylinder is instructed, the control means opens the on-off valve. A control signal composed of an electrical signal is output to the opening / closing means. As a result, the on-off valve is opened, and the bottom chamber of the boom cylinder communicates with either the bottom chamber or the rod chamber of another working member cylinder.

  That is, according to the present invention, communication / blocking between the bottom chamber of the boom cylinder and any one of the bottom chamber and the rod chamber of another working member cylinder can be controlled by an electric signal.

  [3] The invention according to [1], wherein the on-off valve includes a seat valve.

  In this invention comprised in this way, since the on-off valve contains the seat valve which can handle a large flow volume with a small size, it can contribute to size reduction of a valve.

  [4] According to the present invention, in the invention according to [1], the on-off valve is a flow control valve, and the valve control means is for the other work member commanded by the another work member operating device. Control is performed to increase the opening of the flow control valve as the operating speed of the cylinder increases.

  The present invention configured as described above can increase or decrease the flow rate of the pressure oil supplied from the bottom chamber of the boom cylinder to another working member cylinder in conjunction with the operating speed of the other working member cylinder.

  [5] The present invention is the invention described in [1], wherein the work machine is a loading excavator, and the other work member cylinder drives an arm that is coupled to the boom so as to be vertically rotatable. The arm cylinder is configured such that the pipe line is a pipe line connecting the bottom chamber of the boom cylinder and the bottom chamber of the arm cylinder.

  In the present invention configured as described above, the extension speed of the arm cylinder can be increased when the arm cylinder is extended while the boom cylinder is contracted. That is, it is possible to increase the operating speed of the arm when performing the boom lowering / arm pushing combined operation. Accordingly, it is possible to increase the operating speed of the arm when performing the combined operation frequently used when excavating work with the working machine of the loading excavator, that is, the combined boom lowering / arm pressing operation. As a result, it is possible to contribute to improving the efficiency of excavation work by the loading excavator.

  As described above, the present invention is a combined operation of a boom and another work member included in the same work machine, and another operation when performing a combined operation of a boom lowering operation and another work member. The operating speed of the member can be increased by utilizing the pressure oil discharged from the boom cylinder that contracts due to the weight of the work implement, that is, the pressure oil discharged from the bottom chamber of the boom cylinder. Thereby, it can contribute to the improvement of work efficiency.

  An embodiment of a hydraulic drive device for a work machine according to the present invention will be described with reference to FIGS.

  FIG. 1 is a side view showing a loading excavator as an example of a work machine provided with an embodiment of a hydraulic drive apparatus according to the present invention, and FIG. 2 is a configuration of an embodiment of a hydraulic drive apparatus for a work machine according to the present invention. FIG. 3 is a diagram showing an example of the arm opening / closing means shown in FIG. 2, and FIG. 4 is a system configuration relating to control of the arm opening / closing means and bucket opening / closing means by the controller shown in FIG. FIG.

  In the present embodiment, for example, an extra large loading shovel 1 shown in FIG. 1 is provided. The loading excavator 1 includes a traveling body 2 that travels by driving a crawler belt 2a by a traveling motor (not shown), a revolving body 3 that is turnably provided on the traveling body 2 and is driven by a turning motor (not shown), and the turning A work machine 4 having a boom 5, an arm 6, and a bucket 7 is provided on the body 3.

  One end of the boom 5 is pin-coupled to the revolving structure 3 and can be rotated in the vertical direction (arrow S direction). One end of the arm 6 is pin-coupled to the other end of the boom 5, and the tip of the arm 6 can be rotated in a direction toward and away from the revolving unit 3 (arrow T direction). The bucket 7 is pin-coupled to the other end of the arm 6 and is rotatable in the vertical direction (arrow U direction). Moreover, the bucket 7 is comprised so that the lower part may open and close.

  In this embodiment, the hydraulic cylinder that drives the boom 5, that is, the first and second boom cylinders 8 and 9, and the hydraulic cylinder that drives the arm 6, which is a work member different from the boom 5, that is, the arm cylinder 10. And a bucket cylinder 11 that drives a bucket 7, which is a working member different from the boom 5, and an opening / closing cylinder 12 that opens and closes the bucket 7.

  The upward rotation of the boom 5, that is, the raising of the boom is performed by extending the first and second boom cylinders 8 and 9. The downward rotation of the boom 5, that is, the boom lowering is performed by contraction of the first and second boom cylinders 8 and 9. The rotation of the arm 6 in the direction in which the tip of the arm 6 moves away from the revolving body 3, that is, the arm pushing is performed by the extension of the arm cylinder 10. The rotation of the arm 6 in the direction in which the tip of the arm 6 approaches the revolving body 3, that is, the arm pulling is performed by contraction of the arm cylinder 10. The upward rotation of the bucket, that is, the bucket cloud, is performed by the extension of the bucket cylinder 11. The downward rotation of the bucket, that is, the bucket dump is performed by contraction of the bucket cylinder 11. The bucket 7 opens when the opening / closing cylinder 12 contracts and closes when the opening / closing cylinder 12 extends.

  In the present embodiment, as shown in FIG. 2, the pressure supplied to the first and second boom cylinders 8 and 9, the arm cylinder 10, the bucket cylinder 11, and the opening / closing cylinder 12 is driven by the engine 13. A hydraulic pump for discharging oil, that is, first and second main pumps 14 and 15 are provided.

  In the present embodiment, the first and second boom direction switching valves 17 that control the flow of the pressure oil supplied from the first and second main pumps 14 and 15 to the first and second boom cylinders 8 and 9 are also described. , 21, first and second arm directional control valves 16, 20 for controlling the flow of pressure oil supplied from the first and second main pumps 14, 15 to the arm cylinder 10, and the first, second main The first and second bucket directional control valves 15 and 19 for controlling the flow of pressure oil supplied from the pumps 14 and 15 to the bucket cylinder 11 and the first and second main pumps 14 and 15 to the opening / closing cylinder 12. First and second opening / closing direction switching valves 18 and 22 for controlling the flow of pressure oil to be supplied are provided.

  Further, in the present embodiment, as shown in FIG. 2, the boom operating device 24 that commands the operation of the first and second boom cylinders 8 and 9, the operation of the arm cylinder 10, and the bucket cylinder 11. An arm / bucket operating device 25 for instructing the operation and an opening / closing operating device 26 for instructing the operation of the opening / closing cylinder 12 are provided.

  The boom operation device 24 is provided with an operation lever 24a provided to be tiltable in the front-rear direction (left-right direction in FIG. 2) from the neutral position, and an electric signal corresponding to the tilting operation of the operation lever 24a in the front-rear direction, that is, an operation signal. An operation signal output unit that outputs A, for example, a potentiometer 24b is provided.

  The potentiometer 24a has a positive tilt angle (tilt angle> 0 °) when the control lever 24a is tilted forward with the operation lever 24a in the neutral position as a reference (tilt angle 0 °). When the operation lever 24a is tilted backward, a boom operation signal A indicating a negative tilt angle (tilt angle <0 °) is output.

  The tilting direction of the operation lever 24a indicated by the boom operation signal A corresponds to an operation direction command for the first and second boom cylinders 8 and 9. In other words, the fact that the tilt angle indicated by the boom operation signal A is a positive value corresponds to a command to extend the first and second boom cylinders 8 and 9, and the tilt angle indicated by the boom operation signal A is a negative value. This corresponds to a command for contraction of the first and second boom cylinders 8 and 9. Further, the value of the tilt angle of the operation lever 24a indicated by the boom operation signal A corresponds to an operation speed command for the first and second boom cylinders 8 and 9. That is, the positive tilt angle indicated by the boom operation signal A corresponds to the extension speed command of the first and second boom cylinders 8 and 9, and the negative tilt angle indicated by the boom operation signal A is This corresponds to a command for contraction speed of the first and second boom cylinders 8 and 9.

  The arm / bucket operation device 25 is provided with an operation lever 25a that can be tilted in the front-rear direction (left-right direction in FIG. 2) and left-right direction (direction perpendicular to the paper surface) from the neutral position, and the front-rear direction of the operation lever 25a. An operation signal output unit that outputs an electric signal corresponding to the tilting operation, that is, an arm operation signal B, for example, an operation that outputs an electric signal corresponding to the tilting operation in the left-right direction of the operation lever 25a, that is, the bucket operation signal C. A signal output unit, for example, a potentiometer 25c is provided.

  The potentiometer 25b has a positive tilt angle (tilt angle> 0 °) when the control lever 25a is tilted forward when the control lever 25a is in the neutral position (tilt angle 0 °). When the operation lever 25a is tilted backward, the arm operation signal B indicating a negative tilt angle (tilt angle <0 °) is output.

  The tilting direction of the operation lever 25 a indicated by the arm operation signal B corresponds to a command for the operation direction of the arm cylinder 10. In other words, a positive value for the tilt angle indicated by the arm operation signal B corresponds to an extension command for the arm cylinder 10, and a negative value for the arm operation signal B indicates that the tilt angle indicated by the arm operation signal B is for the arm. This corresponds to a command for contraction of the cylinder 10. Further, the value of the tilt angle of the operation lever 25a indicated by the arm operation signal B corresponds to an operation speed command of the arm cylinder 10. In other words, the positive tilt angle indicated by the arm operation signal B corresponds to a command for the extension speed of the arm cylinder 10, and the negative tilt angle indicated by the arm operation signal B is the contraction speed of the arm cylinder 10. Is equivalent to

  The potentiometer 25c has a positive tilt angle (tilt angle> 0) when the control lever 25c is tilted to the right with the operation lever 25a in the neutral position as a reference (tilt angle 0 °). When the operation lever 25a is tilted to the left, the bucket operation signal C indicating a negative tilt angle (tilt angle <0 °) is output.

  The tilt direction of the operation lever 25 c indicated by the bucket operation signal C corresponds to a command for the operation direction of the bucket cylinder 11. That is, a positive value of the tilt angle indicated by the bucket operation signal C corresponds to a command to extend the bucket cylinder 11, and a negative value indicates that the tilt angle indicated by the bucket operation signal C is for the bucket. This corresponds to a contraction command for the cylinder 11. Further, the value of the tilt angle of the operation lever 25 c indicated by the bucket operation signal C corresponds to a command for the operation speed of the bucket cylinder 11. That is, the positive inclination angle indicated by the bucket operation signal C corresponds to the command for the extension speed of the bucket cylinder 11, and the negative inclination angle indicated by the bucket operation signal C is the contraction speed of the bucket cylinder 11. Is equivalent to

  The opening / closing operation device 26 is provided with an operation lever 26a provided so as to be tiltable in the front-rear direction from the neutral position, and an operation signal for outputting an electric signal corresponding to the tilting operation of the operation lever 26a in the front-rear direction, that is, an opening / closing operation signal D. It consists of an electric operation lever device provided with an output part, for example, a potentiometer 26b.

  The potentiometer 26b has a positive tilt angle (tilt angle> 0 °) when the control lever 26a is tilted forward with the operation lever 26a in the neutral position as a reference (tilt angle 0 °). When the operation lever 26a is tilted backward, the open / close operation signal D indicating a negative tilt angle (tilt angle <0 °) is output.

  The tilting direction of the operation lever 26 a indicated by the opening / closing operation signal D corresponds to a command for the operation direction of the opening / closing cylinder 12. That is, a positive value of the tilt angle indicated by the opening / closing operation signal D corresponds to a command to extend the opening / closing cylinder 12, and a negative value of the tilt angle indicated by the opening / closing operation signal D is for opening / closing. This corresponds to a contraction command for the cylinder 12. Further, the value of the tilt angle of the operation lever 26 a indicated by the opening / closing operation signal D corresponds to an operation speed command of the opening / closing cylinder 12. That is, the positive inclination angle indicated by the opening / closing operation signal D corresponds to a command for the extension speed of the opening / closing cylinder 12, and the negative inclination angle indicated by the opening / closing operation signal D is the contraction of the opening / closing cylinder 12. Corresponds to speed command.

  Further, in the present embodiment, as shown in FIG. 2, a controller 27 that outputs control signals a to p in response to the boom operation signal A, arm operation signal B, bucket operation signal C, and opening / closing operation signal D described above is provided. I have. Between this controller 27 and each direction switching valve 15-22 mentioned above, each direction switching valve 15 is controlled by the pilot pressure oil which is controlled by each control signal ap output from the controller 27 and is discharged by a pilot pump (not shown). A proportional solenoid valve (not shown) for generating pilot pressures Pa to Pp to be applied to ˜22 is interposed. That is, the direction switching valves 15 to 22 are switched in response to commands from the operation devices 24 to 26, and control the flow of pressure oil supplied from the first and second main pumps 14 and 15 to the cylinders 8 to 12. It is supposed to be.

  In particular, in the present embodiment, as shown in FIG. 2, the bottom chambers 8a and 9a of the first and second boom cylinders 8 and 9 are different from the first and second boom cylinders 8 and 9. A pipe line 30 is provided to connect either the bottom chamber of the member cylinder or the rod chamber, for example, the bottom chamber 10a of the arm cylinder 10. Further, an arm opening / closing means 28 including an opening / closing valve provided on the pipe 30 and capable of opening / closing the pipe 30, for example, an arm flow control valve 31 (see FIG. 3) is provided. Furthermore, the flow of pressure oil is provided on the pipe line 30 from the arm flow control valve 31 of the arm opening / closing means 28 to the bottom chamber 10a of the arm cylinder 10, and from the bottom chamber 10a of the arm cylinder 10 A check valve 32 is provided to block the flow of pressure oil to the arm flow control valve 31.

  In addition, in the present embodiment, the bottom chambers 8a and 9a of the first and second boom cylinders 8 and 9 and either one of the working member cylinders different from the first and second boom cylinders 8 and 9, For example, a conduit 33 that connects the bottom chamber 11a of the bucket cylinder 11 is provided. Further, there is provided a bucket opening / closing means 29 including an opening / closing valve provided on the pipe 33 and capable of opening and closing the pipe 33, for example, a bucket flow control valve (not shown) having the same configuration as the arm flow control valve 31. Yes. Further, the flow of pressure oil from the bucket flow control valve of the bucket opening / closing means 29 to the bottom chamber 11a of the bucket cylinder 11 is allowed on the conduit 33, and from the bottom chamber 11a of the bucket cylinder 11 to the bucket. There is a check valve 35 for blocking the flow of pressure oil to the flow control valve for use.

  Here, the configuration of the arm opening / closing means 28 will be described in detail with reference to FIG.

  As shown in FIG. 3, the arm opening / closing means 28 includes a portion surrounded by a one-dot chain line. That is, it is composed of the arm flow control valve 31 and the proportional solenoid valve 54 described above. The arm flow control valve 31 includes a portion surrounded by a broken line, and includes, for example, a seat valve 40 and a control valve 52 that controls the seat valve 40.

  The seat valve body 41 of the seat valve 40 is formed with a first pressure receiving surface 41a and a second pressure receiving surface 41b at both ends in the axial direction. Further, a third pressure receiving surface 41 c is formed at an intermediate position in the axial direction of the seat valve body 41. The housing 42 of the seat valve 40 has a valve chamber 43 in which the seat valve body 41 is slidably disposed, an inlet pipe 44 for guiding the pressure oil to the valve chamber 43, and the pressure oil in the valve chamber 43 is discharged. And an outlet seat 45 that is formed around the opening 46 of the outlet passage 45 that opens to the valve chamber 43 and that contacts and separates the seat valve body 41.

  The valve chamber 43 includes a back pressure chamber 43a that applies pressure to the first pressure receiving surface 41a of the seat valve body 41, and an inlet chamber 43b that applies pressure of the inlet conduit 44 to the third pressure receiving surface 41c of the seat valve body 41. The sliding contact surface 43c is in sliding contact with the peripheral side surface of the seat valve body 41. The back pressure chamber 43a is provided with a spring 50 that presses the first pressure receiving surface 41a of the seat valve body 41 and biases the seat valve body 44 in the closing direction.

  A slit 41 d extending in the axial direction is formed on the peripheral side surface of the seat valve body 41. That is, the slit 41d and the sliding contact surface 43c of the valve chamber 41 form an oil passage 48 that guides the pressure oil from the inlet chamber 43b to the back pressure chamber 43a. Further, the oil passage 48 is always opened to the back pressure chamber 43a at the end of the oil passage 48 on the first pressure receiving surface 41a side, and the more the seat valve body 41 is away from the valve seat 47, the more the back pressure chamber 41a is located. A variable throttle 49 that increases the opening is formed.

  The control valve 52 is provided on a connection pipe line 51 that connects the back pressure chamber 43 a and the outlet pipe line 45. The control valve 52 is opened when a pilot pressure is applied to the pilot portion 52a. The degree of opening of the control valve 52 increases as the pilot pressure applied to the pilot section 52a increases, and the flow rate of the pressure oil flowing through the connecting conduit 51 increases accordingly.

  The proportional solenoid valve 54 is a pilot valve that generates a pilot pressure from pressure oil discharged from a pilot pump (not shown). The proportional solenoid valve 54 generates a pilot pressure proportional to the magnitude of the control signal q (current) given to the solenoid unit 54a. The pilot pressure generated by the proportional solenoid valve 54 is guided to the pilot portion 52 a of the control valve 52 through the pilot line 53.

  The arm opening / closing means 28 configured in this way does not generate pilot pressure by the proportional solenoid valve 54 when the control signal q is not applied to the solenoid portion 54a of the proportional solenoid valve 54. For this reason, the control valve 52 does not operate, and the communication conduit 51 is closed by the control valve 52. In the state in which the connecting pipe 51 is closed in this way, the pressure led from the inlet pipe 44 to the back pressure chamber 43a through the inlet chamber 43b and the oil passage 48 is accumulated in the back pressure chamber 41a and the seat valve The first pressure receiving surface 44a of the body 44 is pressed. As a result, the seat valve body 41 is pressed against the valve seat 47 to block the inlet conduit 44 and the outlet conduit 45.

  When the control signal q is given to the solenoid portion 54a of the proportional solenoid valve 54, the proportional solenoid valve 54 is operated to generate a pilot pressure having a magnitude corresponding to the current value of the control signal q. This pilot pressure is guided to the pilot line 53 and applied to the pilot portion 52 a of the control valve 52. Along with this, the control valve 52 opens the communication line 51 with an opening degree corresponding to the magnitude of the pilot pressure.

  When the connecting pipe 51 is thus opened, the pressure oil in the inlet pipe 44 passes through the inlet chamber 43 b, the oil passage 48, the back pressure chamber 43 a, the connecting pipe 51, and the control valve 52. It flows out to the road 45. Thereby, the pressure in the back pressure chamber 43a falls. Accordingly, the pressure in the back pressure chamber 43a and the spring 50 presses the first pressure receiving surface 41a, the force in the inlet chamber 43b presses the third pressure receiving surface 41b, and the pressure in the outlet pipe 45. Is smaller than the sum of the force that presses the second pressure-receiving surface 41c. Accordingly, the seat valve body 41 moves away from the valve seat 47, and the pressure oil in the inlet pipe 44 flows out to the outlet pipe 45 through the inlet chamber 43 b and the opening 46.

  While the seat valve body 41 moves in the direction away from the valve seat 47, the opening degree of the variable throttle 49 increases. When the opening of the variable throttle portion 49 becomes a size commensurate with the opening of the control valve 52, the pressure in the back pressure chamber 43a and the spring 50 presses the first pressure receiving surface 41a. The pressure in 44 is balanced with the total force of the force pressing the third pressure receiving surface 41c and the pressure in the outlet pipe 45 pressing the second pressure receiving surface 41b. The valve body 41 stops. Thus, the opening degree of the seat valve 41, that is, the opening degree of the arm flow control valve 31, is set according to the current value of the control signal q given to the proportional solenoid valve 52, that is, the current value of the control signal q. The larger the is, the larger the opening is set.

  The configuration of the bucket opening / closing means 29 is the same as that of the arm opening / closing means 28 described above.

  Further, as shown in FIG. 4, the controller 27 described above is in a state where the contraction of the first and second boom cylinders 8 and 9 is instructed by the boom operation device 24, and the arm operation device 25 When the extension of the arm cylinder 10 is commanded, the arm valve control means 60 (FIG. 3) controls the arm opening / closing means 28 so that the arm flow control valve 31 of the arm opening / closing means 28 opens. A portion surrounded by a one-dot chain line) is provided.

  This arm valve control means 60 is based on the boom operation signal A output from the potentiometer 24b of the boom operation device 24 and the arm operation signal B output from the potentiometer 25b of the arm / bucket operation device 25. The first and second boom cylinders 8 and 9 are in a state in which the contraction is commanded and the arm cylinder 10 is in a state in which the extension of the arm cylinder 10 is commanded. This determination means includes a boom lowering command determination unit 61, an arm push command determination unit 62, and a boom / arm combined operation command determination unit 63. Further, the arm valve control means 60 has determined by the determination means that the contraction of the first and second boom cylinders 8 and 9 has been commanded and the extension of the arm cylinder 10 has been commanded. At this time, it has a control means 64 for outputting a control signal q to the solenoid portion 54a of the proportional electromagnetic valve 54 of the arm opening / closing means 28 so that the arm flow control valve 31 of the arm opening / closing means 28 is opened.

  The boom lowering command determination unit 61 determines whether or not the boom operation signal A is for instructing the first and second boom cylinders 8 and 9 to contract. A boom lowering command determination signal is output when the command is for contraction. The determination that the boom operation signal A is a command for contracting the first and second boom cylinders 8 and 9 is made when the tilt angle indicated by the boom operation signal A is a negative value.

  The arm push command determination unit 62 determines whether or not the arm operation signal B is a command to press the arm, and outputs an arm push command determination signal when it is a command to press the arm. The determination that the arm operation signal B is a command to push the arm is made when the tilt angle indicated by the arm operation signal B is a positive value.

  The boom / arm combined operation command determination unit 63 determines whether both a boom lowering command determination signal and an arm push command determination signal are input by AND processing, and outputs a combined operation command determination signal when the AND processing is “true”. Output.

  When the composite operation command determination signal is input from the boom / arm composite operation command determination unit 63, the control unit 64 calculates a current value to be given to the solenoid unit 54a of the arm opening / closing unit 28 according to a preset function. A control signal q having this current value is output. The preset function is a function for calculating a current value to be given to the solenoid portion 54a of the arm opening / closing means 28 based on a positive inclination angle indicated by the arm operation signal B. In this function, a larger current value is obtained as the tilt angle of the positive value indicated by the arm operation signal B is larger, that is, as the tilt angle in the forward direction of the operation lever 25a of the arm / bucket operating device 25 is larger. .

  The controller 27 is in a state where the contraction of the first and second boom cylinders 8 and 9 is instructed by the boom operation device 24, and the extension of the bucket cylinder 11 is instructed by the arm / bucket operation device 25. In this state, bucket valve control means 65 (a portion surrounded by a broken line in FIG. 3) for controlling the bucket opening / closing means 29 is provided so that the bucket flow control valve of the bucket opening / closing means 29 is opened. .

  This bucket valve control means 65 is based on the boom operation signal A output from the potentiometer 24b of the boom operation device 24 and the bucket operation signal C output from the arm / bucket operation device 25. And determining means for determining whether or not the contraction of the second boom cylinders 8 and 9 is instructed and the extension of the bucket cylinder 11 is instructed. This determination means includes the above-described boom lowering command determination unit 62, bucket cloud command determination unit 66, and boom / bucket combined operation command determination unit 67. Further, the bucket valve control means 65 has determined by the determination means that the contraction of the first and second boom cylinders 8 and 9 has been commanded and the extension of the bucket cylinder 11 has been commanded. At this time, control means 68 for outputting a control signal r to a solenoid portion of a proportional solenoid valve (not shown) of the bucket opening / closing means 29 is provided so that the bucket flow control valve of the bucket opening / closing means 29 is opened.

  The bucket cloud command determination unit 66 determines whether the bucket operation signal C is for commanding a bucket cloud, and outputs a bucket cloud command determination signal when the bucket cloud command is for commanding a bucket cloud. The determination that the bucket operation signal C instructs the bucket cloud is made when the tilt angle indicated by the bucket operation signal C is a positive value.

  The boom / bucket combined operation command determination unit 68 determines whether both the boom lowering command determination signal and the bucket cloud command determination signal are input by AND processing, and when the AND processing is “true”, the combined operation command determination signal Is output.

  When the composite operation command determination signal is input from the boom / bucket composite operation command determination unit 68, the control unit 68 calculates a current value to be given to the solenoid unit of the bucket opening / closing means 29 according to a preset function. A current value control signal r is output. The preset function is a function for calculating a current value to be given to the solenoid portion of the bucket opening / closing means 29 based on a positive inclination angle indicated by the bucket operation signal C. In this function, the larger the tilt angle of the positive value indicated by the bucket operation signal C, that is, the greater the tilt angle in the right direction of the operation lever 25a of the arm / bucket operation device 25, the larger the current value is obtained. .

  The present embodiment configured as described above operates as the following (1) to (5).

(1) Boom lowering When the operator tilts the operation lever 24a of the boom operation device 24 backward, the potentiometer 24b outputs a boom operation signal A corresponding to the rearward tilt angle of the operation lever 24a to the controller 27. To do. Then, the controller 27 outputs control signals e and m corresponding to the boom operation signal A.

  A proportional solenoid valve (not shown) given the control signal e generates a pilot pressure Pe corresponding to the control signal e. The pilot pressure Pe is applied to the first boom direction switching valve 17, and the first boom direction switching valve 17 is switched accordingly. A proportional solenoid valve (not shown) to which the control signal m is given generates a pilot pressure Pm corresponding to the control signal m. The pilot pressure Pm is applied to the second boom direction switching valve 21, and the second boom direction switching valve 21 is switched accordingly.

  Accordingly, the flow rate of the pressure oil supplied from the first main pump 14A to the rod chambers 8b, 9b of the first and second boom cylinders 8, 9 through the first boom direction switching valve 17 is set. Also, the flow rate of the pressure oil supplied from the second main pump 14B to the rod chambers 8b, 9b of the first and second boom cylinders 8, 9 through the second boom direction switching valve 21 is set. Furthermore, the flow rate of the pressure oil discharged from the bottom chambers 8a and 9a of the first and second boom cylinders 8 and 9 to the hydraulic oil tank 23 via the first and second boom direction switching valves 17 and 21 is set. Is done. As a result, the first and second boom cylinders 8 and 9 extend at a speed corresponding to the forward tilt angle of the operation lever 24a of the boom operation device 24, and the boom raising operation is performed.

(2) Pushing the arm When the operator tilts the operating lever 25a of the arm / bucket operating device 25 forward, the potentiometer 25b sends the arm operating signal B corresponding to the tilting angle of the operating lever 25a in the forward direction to the controller 27. Output to. Then, the controller 27 outputs control signals c and k corresponding to the arm operation signal B.

  A proportional solenoid valve (not shown) to which the control signal c is given generates a pilot pressure Pc corresponding to the control signal c. The pilot pressure Pc is applied to the first arm direction switching valve 16, and the first arm direction switching valve 16 is switched accordingly. The proportional solenoid valve (not shown) to which the control signal k is given generates a pilot pressure Pk corresponding to the control signal k. The pilot pressure Pk is applied to the second arm direction switching valve 20, and the second arm direction switching valve 20 is switched accordingly.

  Thus, the flow rate of the pressure oil supplied from the first main pump 14A to the bottom chamber 10a of the arm cylinder 10 through the first arm direction switching valve 16 is set. Further, the flow rate of the pressure oil supplied from the second main pump 14B to the bottom chamber 10a of the arm cylinder 10 through the second arm direction switching valve 20 is set. Furthermore, the flow rate of the pressure oil discharged from the rod chamber 10b of the arm cylinder 10 to the hydraulic oil tank 23 through the first and second arm direction switching valves 16 and 20 is set. As a result, the arm cylinder 10 extends at a speed corresponding to the forward tilt angle of the operation lever 25a of the arm / bucket operation device 25, and the arm pushing operation is performed.

(3) Bucket Cloud When the operator tilts the operation lever 25a of the arm / bucket operation device 25 in the right direction, the potentiometer 25c outputs the bucket operation signal C corresponding to the tilt angle in the right direction of the operation lever 25a to the controller 27. Output to. Then, the controller 27 outputs control signals a and o corresponding to the bucket operation signal C.

  A proportional solenoid valve (not shown) to which the control signal a is given generates a pilot pressure Pa corresponding to the control signal a. The pilot pressure Pa is applied to the first bucket direction switching valve 15, and the first bucket direction switching valve 15 is switched accordingly. The proportional solenoid valve (not shown) to which the control signal o is given generates a pilot pressure Po corresponding to the control signal o. The pilot pressure Po is applied to the second bucket direction switching valve 19, and the second bucket direction switching valve 19 is switched accordingly.

  Thus, the flow rate of the pressure oil supplied from the first main pump 14A to the bottom chamber 11a of the bucket cylinder 11 through the first bucket direction switching valve 15 is set. Further, the flow rate of the pressure oil supplied from the second main pump 14B to the bottom chamber 11a of the bucket cylinder 11 through the second bucket direction switching valve 19 is set. Furthermore, the flow rate of the pressure oil discharged from the rod chamber 10b of the bucket cylinder 11 to the hydraulic oil tank 23 via the first and second bucket direction switching valves 15 and 19 is set. As a result, the bucket cylinder 11 extends at a speed corresponding to the tilt angle of the operation lever 25a of the arm / bucket operation device 25 in the right direction, and the bucket cloud operation is performed.

(4) Boom lowering / arm pushing combined operation When the operator performs the boom lowering / arm pushing combined operation, the operator tilts the operating lever 24a of the boom operating device 24 in the backward direction and the arm / bucket operating device 25 The operation lever 25a is tilted in the forward direction at the same time. Thereby, the operation described in “(1)” and the operation described in “(2)” are performed in parallel.

  At this time, the following operation is also performed in parallel with the operation described in “(1), (2)”.

  The arm valve control means 60 of the controller 27 determines whether or not the boom operation signal A is a command for lowering the boom by the boom lowering command determination unit 61. Since the operation lever 24a of the boom operation device 24 is now tilted backward, the tilt angle indicated by the boom operation signal A is a negative value. Therefore, the boom lowering command determination unit 61 determines that the boom lowering command has been issued, and outputs a boom lowering command determination signal indicating the determination result to the boom / arm combined operation command determination unit 64.

  While determining whether or not the boom lowering is instructed in this way, the arm valve control means 60 of the controller 27 uses the arm pressing command determining unit 62 to instruct the arm operating signal B to press the arm. It is also determined whether or not. Since the operation lever 25a of the arm / bucket operation device 25 is now tilted forward, the tilt angle indicated by the arm operation signal B is a positive value. Therefore, the arm push command determination unit 62 determines that the arm push has been commanded, and outputs an arm push command determination signal indicating the determination result to the boom / arm combined operation command determination unit 63.

  In this way, when both the boom lowering command determination signal and the arm push command determination signal are input to the boom / arm combined operation command determination unit 63, the result of the AND processing by the boom / arm combined operation command determination unit 63 is “true”. " At this time, the boom / arm combined operation determination unit 63 outputs a combined operation command determination signal to the control means 64. Along with this, the control means 64 calculates a current value corresponding to the positive tilt angle indicated by the arm operation signal B, and uses this current value control signal q for the proportional solenoid valve 54 of the arm opening / closing means 28. Output to the solenoid 54a.

  Accordingly, the arm flow control valve 31 of the arm opening / closing means 28 is operated, and the seat valve 40 of the arm flow control valve 31 is opened. As a result, the pressure oil discharged from the first and second boom cylinders 8 and 9 contracted by the weight of the work implement 4, that is, discharged from the bottom chambers 8 a and 9 a of the first and second boom cylinders 8 and 9. Is supplied to the bottom chamber 10a of the arm cylinder 10 via the arm flow control valve 31 of the arm opening / closing means 28.

  As a result, the pressure oil supplied from the first and second main pumps 14A and 14B to the bottom chamber 10a of the arm cylinder 10 via the first and second arm direction switching valves 16 and 20 and the first and first The cylinder 10 for the arm is supplied with pressure oil supplied from the bottom chambers 8a, 9a of the cylinders 8, 9 for the boom to the bottom chamber 10a of the cylinder 10 for the arm via the flow control valve 31 for the arm opening / closing means 28. Is extended, and the arm is pushed.

  The current value of the control signal q given to the solenoid portion 54a of the arm opening / closing means 28 increases as the tilt angle of the operation lever 25a of the arm / bucket operation device 25 in the forward direction increases. The opening degree of the seat valve 40 of the 28 arm flow control valve 31 increases as the current value of the control signal q given to the solenoid unit 54a increases. Accordingly, the pressure oil supplied from the bottom chambers 8a, 9a of the first and second boom cylinders 8, 9 to the bottom chamber 10a of the arm cylinder 10 via the arm flow control valve 31 of the arm opening / closing means 28 is obtained. The flow rate increases as the tilt angle in the forward direction of the operation lever 25a of the arm / bucket operation device 25 increases.

(5) Boom lowering / bucket cloud combined operation When the operator performs the boom lowering / bucket cloud combined operation, the operator performs the tilting operation of the operation lever 24a of the boom operating device 24 in the rearward direction and the arm / bucket operating device 25. The operation lever 25a is tilted rightward at the same time. Thereby, the operation described in “(1)” and the operation described in “(3)” are performed in parallel.

  At this time, the following operation is also performed in parallel with the operation described in “(1), (3)”.

  The bucket valve control means 65 of the controller 27 determines whether or not the boom operation signal A is for instructing the boom lowering by the boom lowering command determination unit 62. Since the operation lever 24a of the boom operation device 24 is now tilted backward, the tilt angle indicated by the boom operation signal A is a negative value. Therefore, the boom lowering command determination unit 61 determines that the boom lowering command has been issued, and outputs a boom lowering command determination signal indicating the determination result to the boom / arm combined operation command determination unit 64.

  During the determination as to whether or not the boom lowering is instructed in this way, the bucket valve control means 65 of the controller 27 causes the bucket operation signal C to instruct the bat cloud by the bucket cloud instruction determination unit 66. It is also determined whether or not. Since the operation lever 25a of the arm / bucket operation device 25 is now tilted rightward, the tilt angle indicated by the bucket operation signal C is a positive value. Therefore, the bucket cloud command determination unit 66 determines that the bucket cloud has been commanded, and outputs a bucket cloud command determination signal indicating the determination result to the boom / bucket combined operation command determination unit 67.

  As described above, when both the boom lowering command determination signal and the bucket cloud command determination signal are input to the boom / bucket combined operation command determination unit 67, the result of the AND processing by the boom / bucket combined operation command determination unit 67 is “true”. " At this time, the boom / bucket composite operation command determination unit 67 outputs a composite operation command determination signal to the control means 68. Accordingly, the control means 68 calculates a current value corresponding to the positive tilt angle indicated by the bucket operation signal C, and outputs the control signal r having this current value to the solenoid section of the bucket opening / closing means 29.

  Along with this, the bucket flow control valve of the bucket opening / closing means 29 is operated, and the seat valve of the bucket flow control valve is opened. As a result, the pressure oil discharged from the first and second boom cylinders 8 and 9 contracted by the weight of the work implement 4, that is, discharged from the bottom chambers 8 a and 9 a of the first and second boom cylinders 8 and 9. Is supplied to the bottom chamber 11a of the bucket cylinder 11 through a bucket flow control valve (not shown) of the bucket opening / closing means 29.

  As a result, the pressure oil supplied from the first and second main pumps 14A and 14B to the bottom chamber 11a of the bucket cylinder 11 via the first and second bucket direction switching valves 15 and 19 and the first and first The bucket cylinder 11 is extended by the pressure oil supplied from the bottom chambers 8a, 9a of the boom cylinders 8, 9 to the bottom chamber 11a of the bucket cylinder 11 via the bucket flow control valve, and the bucket cloud operation Is done.

  The current value of the control signal r given to the solenoid unit 5 of the bucket opening / closing means 29 increases as the tilt angle of the operation lever 25a of the arm / bucket operation device 25 in the right direction increases. The opening degree of the seat valve 40 of the bucket flow control valve 29 increases as the current value of the control signal r given to the solenoid unit increases. Accordingly, the flow rate of the pressure oil supplied from the bottom chambers 8a, 9a of the first and second boom cylinders 8, 9 to the bottom chamber 11a of the bucket cylinder 11 via the bucket flow control valve of the bucket opening / closing means 29. Increases as the tilt angle in the right direction of the operation lever 25a of the arm / bucket operation device 25 increases.

  According to this embodiment, the following effects can be obtained.

  In the present embodiment, when the boom lowering / arm pushing combined operation is performed, the pressure oil discharged from the first and second boom cylinders 8 and 9 contracted by the weight of the work machine 4, that is, the first and second booms. By utilizing the pressure oil discharged from the bottom chambers 8a, 9a of the cylinders 8 and 9, the flow rate of the pressure oil supplied to the arm cylinder 10 is increased, and the extension speed of the arm cylinder 10, that is, the operation of the arm 6 is increased. Speed can be increased. As a result, work efficiency can be improved.

  In the present embodiment, when the boom lowering / bucket cloud combined operation is performed, the pressure oil discharged from the first and second boom cylinders 8 and 9 contracted by the weight of the work implement 4, that is, the first and second booms. The pressure oil discharged from the bottom chambers 8a, 9a of the cylinders 8, 9a is utilized to increase the flow rate of the pressure oil supplied to the bucket cylinder 11, and the extension speed of the bucket cylinder 11, that is, the operation of the bucket 7 is increased. Speed can be increased. As a result, work efficiency can be improved.

  In the present embodiment, the pressure oil discharged from the bottom chambers 8 a and 9 a of the first and second boom cylinders 8 and 9 that contracts due to the weight of the work machine 4 is utilized. That is, the arm cylinder 10 and the bucket cylinder 11 are driven using the potential energy of the work machine 4. As a result, it can contribute to energy saving.

  Further, the pressure of the pressure oil discharged from the bottom chambers 8a and 9a of the first and second boom cylinders 8 and 9 due to the weight of the work implement 4 is hardly affected by the posture of the work implement 4 and is relatively stable. ing. Thereby, relatively stable pressure oil can be supplied to the arm cylinder 10 and the bucket cylinder 11.

  Further, in the present embodiment, each of the boom opening / closing means 28 and the arm opening / closing means 29 is controlled by the respective control signals q and r, which are electrical signals, so that the first and second boom cylinders 8, Communication between the bottom chambers 8a and 9a of the arm 9 and the bottom chamber 10a of the arm cylinder 10, and the bottom chambers 8a and 9a of the first and second boom cylinders 8 and 9 and the bottom chamber 11a of the bucket cylinder 11. Each of communication and interruption with can be controlled by an electric signal.

  Moreover, this embodiment shall be provided in the loading shovel 1, for example. In the loading excavator 1, excavation work performed by moving the bucket 7 parallel to the ground is frequently used. This excavation work is performed by performing a combined boom lowering / arm pushing operation. That is, this embodiment is effective in improving the efficiency of excavation work by the loading shovel 1.

  Further, since the arm flow control valve 31 and the proportional solenoid valve 54 provided in the arm opening / closing means 28 of the present embodiment are hydraulic devices smaller than the main pump and the direction switching valve, the hydraulic drive device is enlarged. Requires less installation space. The same applies to the bucket opening / closing means 29. That is, in this embodiment, like the super-large loading shovel 1, since the number of main pumps and directional control valves is large and each is large, it is difficult to secure a space for installing new hydraulic equipment. It is effective to provide in.

  Further, in the present embodiment, the arm flow control valve 31 of the arm opening / closing means 28 includes the seat valve 40, which can contribute to the downsizing of the opening / closing valve that opens and closes the pipe line 30. The same applies to the bucket flow control valve of the bucket opening / closing means 29.

  In the present embodiment, either one of the bottom chamber and the rod chamber of another working member cylinder connected to the bottom chambers 8 a and 9 a of the first and second boom cylinders 8 and 9 is connected to the arm cylinder 10. Although the bottom chamber 10a and the bottom chamber 11a of the bucket cylinder 11 are used, the present invention is not limited to this, and the rod chamber 10b of the arm cylinder 10 or the rod chamber 11b of the bucket cylinder 11 may be used.

  In this embodiment, the on-off valve capable of opening and closing the pipe line 30 is the arm flow control valve 31 capable of controlling the flow rate of the pressure oil flowing through the pipe line 30, but the present invention is not limited to this. Alternatively, a valve that simply opens and closes the pipe line 30 may be used. Similarly, the on-off valve that can open and close the pipe line 33 may be a valve that only opens and closes the pipe line 33 instead of the bucket flow control valve.

  In the present embodiment, the operation signal output unit that outputs an electrical signal corresponding to the operation of each operation device 24 to 26 is the potentiometer 24b, 25b, 25c, or 26b of each operation device 24 to 26. Is not limited to this. Each of the first boom direction switching valve 17, the first arm direction switching valve 16, the first bucket direction switching valve 15, and the first opening / closing direction switching valve 18, or the second boom direction switching valve 21, There is provided a pressure sensor for detecting a pilot pressure applied to each of the two-arm direction switching valve 20, the second bucket direction switching valve 19 and the second opening / closing direction switching valve 22 and outputting an electric signal corresponding to the detection result. These pressure sensors may be used as the operation signal output unit.

  In the present embodiment, the arm flow control valve 31 of the arm opening / closing means 28 includes the seat valve 40. However, the present invention is not limited to this and may include a spool valve. . The same applies to the bucket flow control valve of the bucket opening / closing means 29.

  Further, in the present embodiment, the arm flow control valve 31 of the arm opening / closing means 28 is configured to include the control valve 52 and the proportional electromagnetic valve 54. This configuration is because the high-pressure and large-flow pressure oil flows in the connecting conduit 51 in the super-large loading shovel 1, and the present invention is not limited to this. That is, depending on the pressure oil flowing through the connecting pipe 51, the proportional solenoid valve 54 may be omitted and the control valve 52 may be electromagnetic. The same applies to the bucket flow control valve of the bucket opening / closing means 29.

  Moreover, although the working machine provided with this embodiment is the loading shovel 1, the present invention is not limited to this, and can be provided in a working machine provided with a working machine in which a plurality of working members including a boom are connected. Therefore, it may be provided on the backhoe.

1 is a side view showing an extra large loading excavator that is an example of a work machine provided with an embodiment of a hydraulic drive device according to the present invention. 1 is a hydraulic circuit diagram illustrating a configuration of an embodiment of a hydraulic drive device for a work machine according to the present invention. It is a figure which shows an example of the opening-closing means for arms shown in FIG. It is a block diagram which shows the system configuration | structure which concerns on the control of the arm opening / closing means and the bucket opening / closing means by the controller shown in FIG.

Explanation of symbols

1 Loading excavator (work machine)
2 traveling body 3 revolving body 4 working machine 5 boom 6 arm (cylinder for another working member)
7 Bucket (Cylinder for another work member)
8 Cylinder for first boom (hydraulic cylinder)
9 Second boom cylinder (hydraulic cylinder)
10 Arm cylinder (cylinder for another work member)
11 Cylinder for bucket (Cylinder for another work member)
DESCRIPTION OF SYMBOLS 12 Opening-closing cylinder 13 Engine 14A 1st main pump 14B 2nd main pump 15 1st bucket direction switching valve 16 1st arm direction switching valve 17 1st boom direction switching valve 18 1st opening / closing direction switching valve 19 1st 1 bucket direction switching valve 20 first arm direction switching valve 21 first boom direction switching valve 22 first opening / closing direction switching valve 23 hydraulic oil tank 24 boom operating device 25 arm / bucket operating device (separate work) Operation device for parts)
26 Opening / closing operation device 27 Controller 28 Arm opening / closing means 29 Bucket opening / closing means 30 Pipe line 31 Arm flow control valve (opening / closing valve)
32 Check valve 33 Pipe line 40 Seat valve 52 Control valve 54 Proportional solenoid valve 60 Arm valve control means 61 Boom lowering command determination section (determination means)
62 Arm push command determination unit (determination means)
63 Boom / arm combined operation command determination unit (determination means)
64 Control means 65 Bucket valve control means 66 Bucket cloud command determination unit (determination means)
67 Boom / bucket combined operation command determination unit (determination means)
68 Control means

Claims (5)

Provided in a work machine having a work machine including a boom and a work member different from the boom,
A boom cylinder for driving the boom; another work member cylinder for driving the other work member; a main pump for discharging pressure oil to be supplied to the boom cylinder and another work member cylinder; In response to a command from the boom operation device, a boom operation device that commands the operation of the boom cylinder, another work member operation device that commands the operation of the other work member cylinder, the main pump A boom direction switching valve that controls the flow of pressure oil supplied to the boom cylinder, and a pressure supplied from the main pump to the other work member cylinder in response to a command from the other work member operation device. In a hydraulic drive device for a work machine including another work member direction switching valve for controlling the flow of oil,
A pipe line connecting the bottom chamber of the boom cylinder and either the bottom chamber or the rod chamber of the another working member cylinder;
An opening / closing means including an opening / closing valve provided on the pipeline and capable of opening / closing the pipeline;
The boom operating device commanding the operation of the boom cylinder is in a state in which the boom cylinder contraction is commanded, and the operation of the other work member cylinder is commanded by the other work member operating device. And a valve control means for controlling the opening / closing means so that the opening / closing valve is opened when the open / close valve is in a closed state. In the invention of claim 1,
A first operation signal output unit that outputs an electric signal corresponding to the operation of the boom operation device; and a second operation signal output unit that outputs an electric signal corresponding to the operation of the other work member operation device. ,
The on-off valve comprises a valve controlled in response to a control signal comprising an electrical signal;
The valve control means is in a state in which contraction of the boom cylinder is instructed based on an electric signal output from the first and second operation signal output units, and the operation of the other work member cylinder is performed. The determination means that determines whether or not the commanded state is instructed, and the determination means that the boom cylinder is contracted and the operation of the other working member cylinder is commanded. A hydraulic drive device for a work machine, comprising: a control unit that outputs a control signal for controlling the opening / closing unit so that the opening / closing valve is opened when the determination is made. In the invention of claim 1,
The hydraulic drive device for a working machine, wherein the on-off valve includes a seat valve. In the invention of claim 1,
The on-off valve comprises a flow control valve;
The valve control means performs control to increase the opening degree of the flow rate control valve as the operation speed of the another work member cylinder commanded by the other work member operation device is higher. Hydraulic drive device for work machines. In the invention of claim 1,
The work machine is a loading excavator;
The another working member cylinder is an arm cylinder that drives an arm that is coupled to the boom so as to be rotatable in the vertical direction;
The hydraulic drive device for a working machine, wherein the pipe line is a pipe line that connects a bottom chamber of the boom cylinder and a bottom chamber of the arm cylinder.

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