JP2019019900A - Control device of working machine - Google Patents

Abstract

To provide a control device of a working machine which is improved in energy efficiency at the compounding of a boom-down operation and an arm-out operation while suppressing an energy loss at a boom-down single operation.SOLUTION: A controller 91 individually operates a boom regeneration valve 51 and a boom flow rate control valve 46 so as to regenerate a working fluid to a rod chamber 25r from a bottom chamber 25b of a boom cylinder 25 by suppressing a boost of the rod chamber pressure of the boom cylinder 25 at a boom-down single operation. The controller 91 individually operates the boom regeneration valve 51 and the boom flow rate control valve 46 so as to boost the bottom chamber pressure of the boom cylinder 25 on the basis of a boom operation amount and an arm-out operation amount at the compounding of a boom-down operation and an arm-out operation, controls an opening of the regeneration control valve 52 on the basis of the boom operation amount and the arm-out operation amount, and operates main pumps 31, 32 so as to suppress a flow rate supplied to an arm cylinder 26 by an increase of the boom-down operation amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a work machine including a boom cylinder that rotates a boom and a stick cylinder that rotates a stick.

  Conventionally, in a working machine such as a hydraulic excavator equipped with a front working device, for example, when the boom lowering and sticking out, that is, the arm out, are combined, the return oil in the bottom chamber of the boom cylinder is regenerated to the arm cylinder which is a stick cylinder. Are known.

  Specifically, in this work machine, for example, based on the amount of boom operation and the amount of arm operation, a function for determining whether or not a predetermined operation by an attachment is being performed, pressure oil flowing out from the bottom side oil chamber of the boom cylinder And a control device each having a function of controlling inflow to another hydraulic actuator and a function of reducing the discharge amount of the main pump. Then, the control device allows pressure oil to flow out from the bottom side oil chamber of the boom cylinder when the boom lowering operation amount is in a predetermined intermediate operation region and the arm out operation amount is in a predetermined upper limit operation region. Is supplied to another hydraulic actuator, and an operation control signal is output so as to reduce the discharge amount of the main pump. In addition, this control device causes pressure oil flowing out from the bottom side oil chamber of the boom cylinder to flow into the arm cylinder, and a pressure between the pressure of the bottom side oil chamber of the boom cylinder and the pressure of the rod side oil chamber of the arm cylinder. Based on the difference, a reduction width of the discharge amount of the main pump is determined (for example, see Patent Document 1).

JP2013-53498A

  However, in the configuration of Patent Document 1, when the return oil of the bottom chamber of the boom cylinder is regenerated to the rod chamber of the arm cylinder when the boom is lowered, the head chamber pressure of the boom cylinder is not increased, and the arm from the boom cylinder is not increased. The regeneration of hydraulic oil to the cylinder is unstable and poorly reproducible.

  In the configuration of Patent Document 1, when the return oil in the bottom chamber of the boom cylinder is regenerated to the rod chamber of the arm cylinder when the boom is lowered, the pressure between the bottom chamber pressure of the boom cylinder and the rod chamber pressure of the arm cylinder is reduced. Based on the pressure difference, a reduction range of the discharge amount of the main pump is determined. However, increasing the flow rate of hydraulic fluid supplied from the main pump to the rod chamber of the arm cylinder reduces the amount of hydraulic fluid regenerated from the boom cylinder, while reducing the flow rate of hydraulic fluid supplied from the main pump reduces the boom. The amount of hydraulic oil regenerated from increases. Therefore, it is difficult to adjust the main pump flow rate by obtaining the flow rate of the hydraulic oil regenerated from the boom cylinder to the arm cylinder based on the pressure difference between the bottom chamber pressure of the boom cylinder and the rod chamber pressure of the arm cylinder. is there.

  The present invention has been made in view of the above points, and is a control device for a work machine that improves energy efficiency when a boom lowering operation and a stick-out operation are combined while suppressing energy loss during a single boom lowering operation. Is intended to provide.

  The invention according to claim 1 is an operation including at least an airframe, a boom axially connected to the airframe, and a stick axially connected to the boom so as to be rotatable in an in / out direction. Device, engine mounted on the fuselage, variable displacement fluid pressure pump mounted on the fuselage and operated by the engine to discharge the working fluid, boom control tool for operating the boom, and stick control A stick operating body, a boom cylinder operated by a working fluid discharged from a fluid pressure pump to rotate the boom, and a stick cylinder operated by a working fluid discharged from the fluid pressure pump to rotate the stick. A control device for the working machine, the boom lowering operation amount detecting means for detecting the boom lowering operation amount by the boom operating body, and the stick operating body A stick-out operation amount detecting means for detecting the stick-out operation amount, a bottom chamber pressure detecting means for detecting the bottom chamber pressure of the boom cylinder, and a boom regeneration valve for regenerating the working fluid from the bottom chamber of the boom cylinder to the rod chamber; , A flow control valve for guiding the return fluid from the bottom chamber of the boom cylinder to the tank, a regenerative control valve for supplying a part of the return fluid from the bottom chamber of the boom cylinder to the stick cylinder, a boom lowering operation amount detection means, and a stick-out The detection of the operation amount detection means and the detection of the bottom chamber pressure detection means is respectively input, and based on these input detections, operation control signals of at least the boom regeneration valve, the flow control valve, the regenerative control valve, and the fluid pressure pump, respectively. And a controller that outputs the boom series when the boom is lowered alone. The boom lowering operation is performed by outputting an operation control signal that individually operates the boom regeneration valve and the flow control valve so that the working fluid is regenerated from the bottom chamber of the boom cylinder to the rod chamber by suppressing the rise of the rod chamber pressure of the cylinder. Output control signals for individually operating the boom regeneration valve and the flow rate control valve so as to increase the bottom chamber pressure of the boom cylinder based on the boom operation amount and the stick-out operation amount. In addition, it outputs an operation control signal for controlling the opening degree of the regenerative control valve based on the boom operation amount and the stick-out operation amount, and the fluid pressure so as to suppress the flow rate supplied to the stick cylinder by the increase in the boom lowering operation amount. An operation control signal for operating the pump is output.

  According to a second aspect of the present invention, in the work machine control device according to the first aspect, the work machine includes a lower traveling body and an upper revolving body provided on the lower traveling body so as to be capable of swiveling. A turning operation body for turning operation of the upper turning body, and a turning motor that is operated by the working fluid discharged from the fluid pressure pump to turn the upper turning body, and the upper turning body is turned by the turning operation body. The controller includes a swing operation amount detection means for detecting an operation amount, and a swing priority valve for limiting the amount of working fluid supplied to the stick cylinder when the stick operation and the swing operation are combined. The detection of the stick-out operation amount detection means, the bottom chamber pressure detection means, and the turning operation amount detection means is input, and at least the boom regeneration valve is based on these detections. Operation control signals for the flow control valve, regenerative control valve, swivel priority valve, and fluid pressure pump are output, and when the boom lowering operation, stick-out operation, and swiveling operation are combined, the swiveling operation amount and the regenerative control valve An operation control signal for controlling the opening degree of the turning priority valve based on the opening degree is output.

  According to a third aspect of the present invention, when the bottom chamber pressure of the boom cylinder is equal to or lower than a predetermined value, the controller of the work machine control device according to the first or second aspect supplies the boom cylinder to the rod chamber of the boom cylinder. An operation control signal for operating the fluid pressure pump to control the amount of working fluid to be controlled, and at least fluid pressure to control the amount of working fluid supplied to the rod chamber of the arm cylinder based on the stick-out operation amount. An operation control signal for operating the pump is output.

  According to the first aspect of the present invention, at the time of the single operation of lowering the boom, the increase in the rod chamber pressure of the boom cylinder is suppressed and the working fluid is regenerated from the bottom chamber of the boom cylinder to the rod chamber. And energy loss can be suppressed. Further, when the boom lowering operation and the arm out operation are combined, the boom cylinder bottom chamber pressure is increased so that the return fluid from the boom cylinder bottom chamber is regenerated to the stick cylinder, and the boom lowering operation amount and the arm out operation are increased. By adjusting the opening of the regenerative control valve and the fluid pressure pump capacity according to the amount, the regeneration flow rate to the stick cylinder can be increased and the pump flow rate can be reduced, and the energy efficiency can be improved.

  According to the second aspect of the present invention, when the boom lowering operation, the stick-out operation, and the turning operation are combined, the amount of working fluid supplied to the turning motor flows into the rod chamber of the stick cylinder, and the stick cylinder from the bottom chamber of the boom cylinder. Since the opening degree of the swing priority valve is adjusted so that the regeneration flow rate flowing through the rod chamber does not decrease, operability can be ensured and energy efficiency can be improved.

  According to the invention of claim 3, when the bottom chamber pressure of the boom cylinder is not more than a predetermined value, for example, when the working device is grounded, the amount of working fluid supplied to the rod chamber of the boom cylinder is controlled, and at least a stick-out operation is performed. Since the amount of working fluid from the fluid pressure pump to the rod chamber of the stick cylinder is controlled based on the amount, the work device can quickly and smoothly transition from operation in a non-grounded state to a grounded state such as a bucket. it can.

It is a circuit diagram showing one embodiment of a control device of a work machine concerning the present invention. It is a block diagram which shows the input / output relationship of a control apparatus same as the above. It is a calculation block diagram which shows the 1st control part of a control apparatus same as the above. It is a calculation block diagram which shows the 2nd control part of a control apparatus same as the above. It is a calculation block diagram which shows the 3rd control part of a control apparatus same as the above. It is a side view of the working machine carrying a control apparatus same as the above.

  Hereinafter, the present invention will be described in detail based on one embodiment shown in FIGS.

  FIG. 6 shows a work machine 10 of a hydraulic excavator type. The work machine 10 includes a machine body 11, a cab 12, and a work device 13.

  The airframe 11 includes a lower traveling body 15 and an upper revolving body 16 provided on the lower traveling body 15 so as to be able to swivel. The machine body 11 includes a traveling motor 17 that drives the lower traveling body 15. Further, the machine body 11 includes a turning motor 18 that drives the upper turning body 16.

  The cab 12 and the work device 13 are mounted on the body 11 (upper swing body 16), respectively. The work device 13 includes a boom 21, an arm 22 that is a stick, and a bucket 23. The work device 13 includes a boom cylinder 25, an arm cylinder 26 that is a stick cylinder, and a bucket cylinder 27.

  The base end of the boom 21 is pivotally supported by the upper swing body 16 so as to be rotatable in the vertical direction. The arm 22 is rotatably supported at the tip of the boom 21. The bucket 23 is pivotally supported at the tip of the arm 22 so as to be rotatable. The boom 21 is rotated by the boom cylinder 25, the arm 22 is rotated by the arm cylinder 26, and the bucket 23 is rotated by the bucket cylinder 27.

  A hydraulic system for the work machine 10 shown in FIG. 1 is mounted on the work machine 10 shown in FIG. The working fluid is hydraulic oil.

  (First and second) main pumps 31 and 32 which are variable displacement fluid pressure pumps mounted on the airframe 11 (FIG. 6) are driven by an engine 33 mounted on the airframe 11 (FIG. 6). . The discharge lines L1 and L2 of the main pumps 31 and 32 are connected to a control valve 34 for distributing and controlling the hydraulic oil discharged from the main pumps 31 and 32, and a plurality of actuator control spools constituting the control valve 34 The output passages of the hydraulic oil whose direction and flow rate are controlled by the motor are connected to the hydraulic actuators such as the left and right traveling motors 17, 17, the swing motor 18, the boom cylinder 25, the arm cylinder 26, and the bucket cylinder 27. ing.

  A center bypass passage 35 in the control valve 34 has (first and second) relief valves 36L and 36R for taking out a negative flow control pressure (hereinafter referred to as negative control pressure) and a negative flow control pressure passage, ie, (first And second) negative control pressure passages 37L, 37R are provided. The center bypass passage 35 is connected to the tank T. The main pumps 31 and 32 are controlled by either the negative control pressure derived by the negative control pressure passages 37L and 37R or the secondary pressure of the (first and second) electromagnetic proportional valves 38L and 38R ( First and second) variable capacity means 31a, 32a are provided. That is, the negative control pressure passages 37L and 37R and the secondary side of the electromagnetic proportional valves 38L and 38R are connected to the (first and second) shuttle valves 39L and 39R. By these shuttle valves 39L and 39R, the high pressure of the negative control pressure of the control valve 34 and the secondary pressure of the electromagnetic proportional valves 38L and 38R is selected and input to the capacity variable means 31a and 32a. The negative control pressure increases as the actuator control spools of the control valve 34 are closer to the neutral position where the actuator is stopped, and the capacity variable means 31a, 32a controls the discharge flow rates of the main pumps 31, 32 to be reduced. Further, as the secondary pressure of the electromagnetic proportional valves 38L, 38R is increased, the capacity variable means 31a, 32a is controlled to decrease the discharge flow rate of the main pumps 31, 32.

  Further, a pilot pump 41 is connected to the main pump 32, and a discharge port of the pilot pump 41 is connected to a valve block 42. Pressure oil supplied from the pilot pump 41 via the valve block 42 is controlled by a remote controller. Supplied to valves and solenoid proportional valves.

  The control valve 34 has (first and second) boom flow control valves 45 and 46 for the boom cylinder 25 and (first and second) stick flow rates for the arm cylinder 26 as an actuator control spool. Arm flow control valves 47 and 48, which are control valves, a swing flow control valve 49 for the swing motor 18, and the like are arranged. The left and right travel flow control valves for the travel motor and the bucket flow control valves for the bucket cylinder are not shown for the sake of clarity. The control valve 34 also has a boom regeneration valve 51 for regenerating the pressure oil in the bottom chamber 25b of the boom cylinder 25 into the rod chamber 25r and regenerating the energy of the working device 13 (FIG. 6) during the boom lowering operation. Is arranged. Furthermore, in the hydraulic system, when the boom lowering operation and the arm out operation are combined, a part of the return oil in the bottom chamber 25b of the boom cylinder 25 is regenerated to the arm cylinder 26, and the energy that the working device 13 (FIG. 6) has is stored. A regeneration control valve 52 for regeneration is disposed. Further, the control valve 34 is provided with an arm flow control valve 47, that is, a swing priority valve 53 for limiting the amount of working fluid supplied to the arm cylinder 26 when the arm operation and the swing operation are combined. For example, a boom flow control valve 46, an arm flow control valve 47, a turning flow control valve 49, a left travel flow control valve, and the like are connected to the discharge line L1 of the main pump 32 to supply hydraulic oil from the main pump 31. The boom flow control valve 45, the arm flow control valve 48, the bucket flow control valve, the right travel flow control valve, etc. are connected to the discharge line L2 of the main pump 32 so that hydraulic oil is supplied from the main pump 32. It has become.

  The boom flow rate control valve 45 is connected to the bottom chamber 25b and the rod chamber 25r of the boom cylinder 25 via output passages 55 and 56. The boom flow rate control valve 46 is connected to the bottom chamber 25b of the boom cylinder 25 via an output passage 58 connected to the output passage 55. The boom flow rate control valve 46 is a flow rate control valve (return flow rate control valve) that guides return oil from the bottom chamber 25b of the boom cylinder 25 to the tank T. Further, the boom flow rate control valve 46 is controlled by a solenoid proportional valve 59 to lower the boom.

  The arm flow control valve 47 is connected to the bottom chamber 26b and the rod chamber 26r of the arm cylinder 26 via the output passages 61 and 62. The arm flow control valve 48 is connected to the bottom chamber 26b and the rod chamber 26r of the arm cylinder 26 via output passages 63 and 64 connected to the output passages 61 and 62.

  The turning flow rate control valve 49 is connected to the turning motor 18 via output passages 66 and 67.

  The boom regeneration valve 51 is connected to the output passage 55 and is connected to the output passage 56 via a check valve 68. That is, the boom regeneration valve 51 is connected between the output passages 55 and 56. The operation of the boom regeneration valve 51 is controlled by an electromagnetic proportional valve 69.

  The regenerative control valve 52 is constituted by a block different from the control valve 34, for example. The regenerative control valve 52 is connected to a branch passage 71 branched from the output passage 55 and connected to a discharge line L2 (center bypass passage 35) of the main pump 32 via a check valve 72. Yes. That is, the regeneration control valve 52 is connected between the output passage 55 and the discharge line L2. In other words, the hydraulic oil from the bottom chamber 25b of the boom cylinder 25 is joined to the upstream side of the arm flow control valve 48 branched from the center bypass passage 35 by the regenerative control valve 52. The operation of the regenerative control valve 52 is controlled by an electromagnetic proportional valve 73.

  The turning priority valve 53 is connected to the branch passage 75 branched from the discharge line L1 of the main pump 31 and is connected to the arm flow control valve 47 via the passage 76. A center bypass passage 35 is connected to the passage 76 via a check valve 77. The operation of the swing priority valve 53 is controlled by an electromagnetic proportional valve 78.

  In addition, the traveling by the lower traveling body 15 shown in FIG. 6, the turning of the upper revolving body 16, the rotation of the boom 21, the arm 22, and the bucket 23 are respectively operated by levers and pedals by an operator seated in the cab 12. It is controlled according to body operation. For example, in the present embodiment, as shown in FIG. 1, as the operating body, a boom remote control valve 81 as a boom operating body, an arm remote control valve 82 as a stick operating body (arm operating body), and A turning remote control valve 83 or the like as a turning operation body is provided. Note that the illustration of the traveling operation body that operates traveling and the bucket operation body that operates rotation of the bucket 23 is omitted for the sake of clarity.

  The boom remote control valve 81 can perform at least a boom lowering operation among the boom raising / lowering operations. In the present embodiment, the boom remote control valve 81 controls the boom lowering operation of the boom flow rate control valve 45 by the pilot pressure, and controls the boom lowering operation of the boom flow rate control valve 46 via the electromagnetic proportional valve 59. Further, the boom lowering operation amount by the boom remote control valve 81 is detected by detecting the boom lowering pilot pressure of the boom remote control valve 81 by the pressure sensor 85 as the boom lowering operation amount detecting means.

  The arm remote control valve 82 can perform at least an arm-out operation in a stick-in / out operation, that is, an arm-in / out operation. In the present embodiment, the arm remote control valve 82 controls the arm-out operation of the arm flow control valves 47 and 48 by the pilot pressure. Further, the arm-out operation amount by the arm remote control valve 82 is detected by detecting the arm-out pilot pressure which is the stick-out pilot pressure by the pressure sensor 86 as the stick-out operation amount detection means (arm-out operation amount detection means). The

  The turning remote control valve 83 can be turned. In the present embodiment, the swing remote control valve 83 controls the operation of the swing flow rate control valve 49 with the pilot pressure. Further, a shuttle valve 87 for selecting a high left / right turning pilot pressure is connected to the turning remote control valve 83. The turning operation amount by the turning remote control valve 83 is detected by detecting the turning pilot pressure output from the shuttle valve 87 by the pressure sensor 88 as the turning operation amount detecting means. Further, the bottom chamber pressure of the boom cylinder 25, that is, the boom bottom chamber pressure is detected by a pressure sensor 89 as a bottom chamber pressure detecting means.

  The pressure sensors 85, 86, 88 and 89 are connected to the controller 91. That is, as shown in FIGS. 1 and 2, detection signals from the pressure sensors 85, 86, 88, and 89 are input to the controller 91.

  The controller 91 outputs an operation control signal to various electromagnetic proportional valves. For example, in this embodiment, from this controller 91, the electromagnetic proportional valves 38L and 38R of the main pumps 31 and 32, the electromagnetic proportional valve 69 for controlling the boom regeneration valve 51, and the electromagnetic proportional valve for controlling the regenerative control valve 52 are used. Operation control signals of the valve 73, the electromagnetic proportional valve 59 of the boom flow control valve 46, and the electromagnetic proportional valve 78 of the swing priority valve 53 are output. That is, the controller 91 receives the detections of the pressure sensors 85, 86, 88, and 89, respectively, and based on the input detections, the main pumps 31, 32, the boom regeneration valve 51, the regenerative control valve shown in FIG. 52 and the operation control signals of the boom flow rate control valve 46 are output.

  Next, the configuration of the controller 91 will be described.

  In the controller 91, first to third control units 93 to 95 are set.

  The first control unit 93 shown in FIGS. 1 to 3 controls the regenerative control valve 52 and the turning priority valve 53. Detection results of the pressure sensor 85, the pressure sensor 86, and the pressure sensor 88 are input to the first control unit 93, and an operation control signal for controlling the regenerative control valve 52 and a turn priority are controlled by a control calculation. Operation control signals for controlling the valves 53 are individually output.

  More specifically, the first control unit 93 sets a swing priority valve pilot pressure table T1 (which sets an operation control signal (pilot pressure) of the swing priority valve 53 based on the swing pilot pressure Psw which is a detection signal of the pressure sensor 88. Hereinafter, it is simply referred to as a table T1). In addition, the first control unit 93 sets the opening of the regenerative control valve 52 based on the boom lowering pilot pressure Pbd, which is a detection signal of the pressure sensor 85, that is, a regenerative control valve opening area table T2 (hereinafter referred to as an opening area). Simply called table T2). Further, the first controller 93 sets a compensation gain (for example, 0 to 1.0) for adjusting the opening area of the regenerative control valve 52 based on the arm-out pilot pressure Pao that is a detection signal of the pressure sensor 86. A regenerative control valve compensation gain table T3 (hereinafter simply referred to as table T3) is provided. The first controller 93 includes a multiplier 101 that multiplies the opening area set in the table T2 and the compensation gain set in the table T3. That is, the opening area of the regeneration control valve 52 set according to the boom lowering operation amount is weighted so as to increase as the arm out operation amount increases according to the arm out operation amount. Further, the first controller 93 adjusts the operation control signal (pilot pressure) of the electromagnetic proportional valve 78 for controlling the swing priority valve 53 based on the opening area of the regeneration control valve 52 obtained by the multiplier 101. A turning priority valve compensation gain table T4 (hereinafter simply referred to as table T4) for setting a compensation gain (for example, 0 to 1.0) is provided. The first controller 93 multiplies the operation control signal (pilot pressure) set in the table T1 and the compensation gain set in the table T4 to control the proportional solenoid valve 78 for controlling the swing priority valve 53. A multiplier 102 is provided for outputting the operation control signal. That is, the opening of the turning priority valve 53 set according to the turning operation amount, that is, the opening area, depends on the opening area of the regenerative control valve 52 according to the boom lowering operation amount weighted according to the arm out operation amount. Thus, in the present embodiment, weighting is performed so that the larger the opening area of the regeneration control valve 52, the smaller the opening area. The first control unit 93 converts the opening area of the regenerative control valve 52 obtained by the multiplier 101 into an operation control signal (pilot pressure) of the electromagnetic proportional valve 73 for controlling the regenerative control valve 52. A regenerative control valve pilot pressure table T5 (hereinafter simply referred to as table T5) is provided.

  The second control unit 94 shown in FIGS. 1, 2, and 4 controls the boom flow rate control valve 46 and the boom regeneration valve 51. The detection results of the pressure sensor 85 and the pressure sensor 86 are input to the second control unit 94, and an operation control signal of the electromagnetic proportional valve 59 for controlling the boom flow rate control valve 46, and An operation control signal of an electromagnetic proportional valve 69 for controlling the boom regeneration valve 51 is output.

  This second control unit 94 sets the opening of the boom flow control valve 46 based on the boom lowering pilot pressure Pbd that is a detection signal of the pressure sensor 85, that is, a boom flow control valve opening area table T6 (hereinafter referred to as an opening area table T6). Simply a table T6). The second control unit 94 also sets a boom regeneration valve opening area table T7 (hereinafter, referred to as an opening area of the boom regeneration valve 51 based on a boom lowering pilot pressure Pbd, which is a detection signal of the pressure sensor 85, that is, an opening area). Simply a table T7). Further, the second control unit 94 sets a compensation gain table for adjusting the opening area of the boom flow control valve 46 based on the arm-out pilot pressure Pao that is a detection signal of the pressure sensor 86. T8 (hereinafter simply referred to as table T8) is provided. The second control unit 94 also sets a boom regeneration valve compensation gain table T9 for setting a compensation gain for adjusting the opening area of the boom regeneration valve 51 based on the arm-out pilot pressure Pao that is a detection signal of the pressure sensor 86. (Hereinafter simply referred to as table T9). Further, the second control unit 94 includes a multiplier 104 that multiplies the opening area set in the table T6 and the compensation gain set in the table T8. That is, the opening area of the boom flow rate control valve 46 set according to the boom lowering operation amount is weighted so as to decrease as the arm out operation amount increases in the present embodiment according to the arm out operation amount. The second control unit 94 includes a multiplier 105 that multiplies the opening area set in the table T7 and the compensation gain set in the table T9. That is, the opening area of the boom regeneration valve 51 set according to the boom lowering operation amount is weighted so as to increase as the arm out operation amount increases according to the arm out operation amount. Further, the second control unit 94 uses the opening area of the boom flow control valve 46 obtained by the multiplier 104 as an operation control signal (pilot pressure) of the electromagnetic proportional valve 59 for controlling the boom flow control valve 46. A boom flow control valve pilot pressure table T10 (hereinafter simply referred to as table T10) to be converted is provided. Then, the second control unit 94 converts the opening area of the boom regeneration valve 51 obtained by the multiplier 105 into an operation control signal (pilot pressure) of the electromagnetic proportional valve 69 for controlling the boom regeneration valve 51. A boom regeneration valve pilot pressure table T11 (hereinafter simply referred to as table T11) is provided.

  Moreover, the 3rd control part 95 shown by FIG.1, FIG.2, and FIG.5 controls the main pumps 31 and 32. FIG. The third control unit 95 receives the detection results of the pressure sensors 85, 86, 88, 89, and the operation calculation signals of the electromagnetic proportional valves 38L, 38R for controlling the main pumps 31, 32 are obtained by the control calculation. Each is output.

  The third control unit 95 includes a boom lowering pump required capacity table T12 (hereinafter simply referred to as a table T12) for setting a boom lowering pump flow rate based on a boom lowering pilot pressure Pbd that is a detection signal of the pressure sensor 85. Yes. Further, the third control unit 95 sets the first arm pump required capacity table T13 (hereinafter referred to as the pump flow rate to be supplied to the arm flow control valve 47 based on the arm out pilot pressure Pao which is the detection signal of the pressure sensor 86). Simply referred to as a table T13). Further, the third control unit 95 sets a second arm pump required capacity table T14 (hereinafter referred to as a pump flow rate to be supplied to the arm flow control valve 48 based on the arm out pilot pressure Pao which is a detection signal of the pressure sensor 86). Simply referred to as a table T14). Further, the third control unit 95 sets the pump flow capacity table T15 (hereinafter simply referred to as the table T15) for setting the pump flow rate to be supplied to the swing flow rate control valve 49 based on the swing pilot pressure Psw that is the detection signal of the pressure sensor 88. Is provided). Further, the third control unit 95 sets a compensation gain (for example, 0 to 1.0) for controlling the flow rate of the main pumps 31 and 32 based on the boom bottom chamber pressure Pbb which is a detection signal of the pressure sensor 89. A pump flow rate compensation gain table T16 (hereinafter simply referred to as table T16) is provided. Further, the third control unit 95 adjusts the pump flow rate supplied to the arm flow rate control valve 47 based on the boom lowering pilot pressure Pbd that is a detection signal of the pressure sensor 85 (for example, 0 to 1.0). Is provided with a first arm pump flow rate compensation gain table T17 (hereinafter simply referred to as table T17). Further, the third control unit 95 adjusts the pump flow rate supplied to the arm flow rate control valve 48 based on the boom lowering pilot pressure Pbd that is a detection signal of the pressure sensor 85 (for example, 0 to 1.0). Is provided with a second arm pump flow rate compensation gain table T18 (hereinafter simply referred to as table T18).

  The third control unit 95 includes a multiplier 107 that multiplies the pump capacity set in the table T12 and the compensation gain set in the table T16. Further, the third control unit 95 includes a maximum value selector 108 that selects a large compensation gain by comparing the compensation gain set in the table T16 with the compensation gain set in the table T18. The third control unit 95 includes a multiplier 109 that multiplies the pump capacity set in the table T14 and the compensation gain set in the maximum value selector 108. Further, the third control unit 95 includes a maximum value selector 111 that selects a large compensation gain by comparing the compensation gain set in the table T16 with the compensation gain set in the table T17. The third control unit 95 includes a multiplier 112 that multiplies the pump capacity set in the table T13 and the compensation gain set in the maximum value selector 111. Further, the third control unit 95 compares the boom lowering pump capacity obtained by the multiplier 107 with the pump capacity of the arm flow control valve 48 obtained by the multiplier 109 and selects the maximum value. A selector 114 is provided. The third control unit 95 compares the pump capacity of the arm flow control valve 47 obtained by the multiplier 112 with the swing pump capacity set in the table T15 and selects a maximum value. A container 115 is provided. The third control unit 95 converts the pump capacity obtained by the maximum value selectors 114 and 115 into operation control signals for the electromagnetic proportional valves 38R and 38L for controlling the negative control pressures of the main pumps 32 and 31, respectively. (First and second) negative control pressure conversion tables T19 and T20 (hereinafter simply referred to as tables T19 and T20) are provided.

  Next, the operation of the illustrated embodiment will be described.

(I) Boom lowering single operation In the second control unit 94 shown in FIGS. 1, 2, and 4, the boom lowering pilot pressure Pbd input from the pressure sensor 85 is used according to the characteristics of the table T6. The opening area of the boom flow control valve 46 is set. Similarly, the opening area of the boom regeneration valve 51 is set according to the characteristics of the table T7 based on the boom lowering pilot pressure Pbd input from the pressure sensor 85.

  At this time, since the arm-out operation is not performed, the arm-out pilot pressure Pao input from the pressure sensor 86 becomes 0, and the characteristics of the tables T8 and T9 are based on the arm-out pilot pressure Pao based on the characteristics of the tables T8 and T9. The compensation gain set in accordance with is 1.0.

  Therefore, the opening area of the boom flow control valve 46 and the opening area of the boom regeneration valve 51 set in accordance with the characteristics of the tables T6 and T7 are output as they are from the multipliers 104 and 105, and the operation generated via the table T10 is generated. An electromagnetic proportional valve 59 for controlling the boom flow control valve 46 is controlled by the control signal, and an electromagnetic proportional valve 69 for controlling the boom regeneration valve 51 is controlled by the operation control signal generated via the table T11.

  In such a boom lowering single operation, when the rod chamber pressure of the boom cylinder 25 rises, the pressure of the main pump 32 that supplies hydraulic oil to the rod chamber 25r of the boom cylinder 25 rises and wastes energy. Become. Therefore, in the present embodiment, in the boom lowering single operation, the boom flow control valve 46 (boom lowering position 46a) that restricts the opening area of the boom regeneration valve 51 and releases the return oil from the bottom chamber 25b of the boom cylinder 25 to the tank T. The opening characteristics of the tables T6 and T7 are set so that the return opening area is increased and the increase in the rod chamber pressure of the boom cylinder 25 is suppressed, that is, the rod chamber pressure is lowered. That is, the controller 91 controls the boom regeneration valve 51 and the boom flow rate so as to regenerate the hydraulic oil from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 25r while suppressing the increase in the rod chamber pressure of the boom cylinder 25 during the boom lowering operation alone. Operation control signals for individually operating the control valves 46 are output.

  As a result, the boom flow control valve 45 is controlled to the boom lowering position 45a side according to the boom lowering operation amount, and the boom flow control valve 46 is controlled by the electromagnetic proportional valve 59 according to the boom lowering operation amount. The boom regeneration valve 51 is controlled to a position where the regeneration flow rate from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 25r is reduced by the electromagnetic proportional valve 69 in accordance with the boom lowering operation amount.

  Further, in the third control unit 95 shown in FIGS. 1, 2, and 5, the pump capacity is set according to the characteristics of the table T12 based on the boom lowering pilot pressure Pbd inputted from the pressure sensor 85. Is done. Further, based on the boom bottom chamber pressure Pbb input from the pressure sensor 89, a compensation gain is set according to the characteristics of the table T16, and this compensation gain is multiplied by the pump capacity output from the table T12 by the multiplier 107. . The pump capacity obtained by the multiplier 107 is input to the table T19 via the maximum value selector 114, and the negative control pressure of the main pump 32 is set by the electromagnetic proportional valve 38R for controlling the main pump 32.

  For example, when the bucket 23 (working device 13) is in the air, the boom bottom chamber pressure Pbb is relatively large, so a relatively small compensation gain (a value smaller than 1.0) is set according to the characteristics of the table T16. Is done. Accordingly, the return oil from the bottom chamber 25b of the boom cylinder 25 is regenerated from the boom regeneration valve 51 whose opening area is restricted to the rod chamber 25r of the boom cylinder 25 with the flow rate supplied from the main pump 32 suppressed. While flowing, the fuel flows from the return opening (boom lowered position 46a) of the boom flow control valve 46 to the tank T. That is, the hydraulic oil supplied to the rod chamber 25r of the boom cylinder 25 can be 100% covered by the hydraulic oil from the bottom chamber 25b.

(II) Combined operation of boom lowering and arm out In the second control unit 94 shown in FIGS. 1, 2, and 4, the table T6 is set based on the boom lowering pilot pressure Pbd input from the pressure sensor 85. The opening area of the boom flow control valve 46 is set according to the characteristics. Similarly, the opening area of the boom regeneration valve 51 is set according to the characteristics of the table T7 based on the boom lowering pilot pressure Pbd input from the pressure sensor 85.

  Further, compensation gains are set according to the characteristics of the tables T8 and T9 based on the arm-out pilot pressure Pao input from the pressure sensor 86.

  The multiplier 104 multiplies the opening area set according to the characteristics of the table T6 by the compensation gain set according to the characteristics of the table T8, and controls the boom flow control valve 46 via the table T10. The electromagnetic proportional valve 59 is controlled.

  The multiplier 105 multiplies the opening area set according to the characteristics of the table T7 by the compensation gain set according to the characteristics of the table T9, and the electromagnetic for controlling the boom regeneration valve 51 via the table T11. The proportional valve 69 is controlled.

  When the arm-out pilot pressure Pao input from the pressure sensor 86 becomes relatively large due to the characteristics of the table T8, the compensation gain output from the table T8 is set to a value smaller than 1.0. On the other hand, when the armout pilot pressure Pao input from the pressure sensor 86 becomes relatively large due to the characteristics of the table T9, the compensation gain output from the table T9 is set to a value larger than 1.0.

  Therefore, when the boom lowering operation and the arm out operation are combined, the characteristics of the tables T8 and T9 are adjusted, and the opening area of the boom regeneration valve 51 that regenerates the return oil from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 25r. The opening area on the return side of the boom flow rate control valve 46 for allowing the return oil in the bottom chamber 25b of the boom cylinder 25 to escape to the tank T is suppressed more than when the boom is lowered alone.

  By these actions, the boom bottom chamber pressure Pbb can be increased so that the return oil can be efficiently regenerated from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 26r of the arm cylinder 26.

  In the first controller 93 shown in FIG. 3, the opening area is set according to the characteristics of the table T2 based on the boom lowering pilot pressure Pbd inputted from the pressure sensor 85. On the other hand, a compensation gain is set according to the characteristics of the table T3 based on the arm-out pilot pressure Pao input from the pressure sensor 86. Further, the opening area set according to the characteristics of the table T2 and the compensation gain set according to the characteristics of the table T3 are multiplied by the multiplier 101 to obtain the opening area of the regenerative control valve 52. The opening area obtained by the multiplier 101 is converted into a pilot pressure according to the characteristics of the table T5, and the electromagnetic proportional valve 73 of the regenerative control valve 52 is controlled.

  Here, the table T2 has a characteristic that the opening area increases as the boom lowering pilot pressure Pbd increases. On the other hand, the table T3 has a characteristic that the compensation gain increases as the arm-out pilot pressure Pao increases, and becomes 1.0 at full operation.

  Thus, the controller 91 controls the boom regeneration valve 51 and the boom flow control valve 46 to increase the boom bottom chamber pressure Pbb based on the boom operation amount and the stick-out operation amount when the boom lowering operation and the arm-out operation are combined. And an operation control signal for controlling the opening, that is, the opening area of the regenerative control valve 52 based on the boom operation amount and the arm out operation amount.

  As a result, the boom flow control valve 45 is controlled to the boom lowering position 45a side according to the boom lowering operation amount, and the boom flow control valve 46 is adjusted to the boom lowering operation amount weighted in the table T8 based on the arm out operation amount. Accordingly, the electromagnetic proportional valve 59 is controlled to the boom lowering position 46a side, and the arm flow control valves 47 and 48 are controlled to the arm-out positions 47a and 48a, which are stick-out positions, according to the arm-out operation amount. Further, the boom regeneration valve 51 increases the regeneration flow rate from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 25r by the electromagnetic proportional valve 69 in accordance with the boom lowering operation amount weighted in the table T9 based on the arm out operation amount. Controlled by position. Further, the regeneration control valve 52 regenerates from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 26r of the arm cylinder 26 by the electromagnetic proportional valve 73 in accordance with the boom lowering operation amount weighted in the table T3 based on the arm out operation amount. It is controlled to the position where the flow rate is set.

  Therefore, when the boom lowering operation and the arm out operation are combined, the opening area of the regenerative control valve 52 is controlled according to the boom lowering operation amount and the arm out operation amount, and the pressure oil in the bottom chamber 25b of the boom cylinder 25 is Regenerated in the rod chamber 26r of the cylinder 26. As a result, the hydraulic oil supplied to the rod chamber 25r of the boom cylinder 25 can be covered by about 70% with the hydraulic oil from the bottom chamber 25b.

  Furthermore, in the third control unit 95 shown in FIG. 5, when the boom lowering operation and the arm out operation are combined, the pump is pumped according to the characteristics of the table T12 based on the boom lowering pilot pressure Pbd inputted from the pressure sensor 85. The capacity is set. Further, based on the arm-out pilot pressure Pao input from the pressure sensor 86, the pump capacity of the arm flow control valve 47 is set according to the characteristics of the table T13, and the pump capacity of the arm flow control valve 48 is set in the table T14.

  A compensation gain is set according to the characteristics of the tables T17 and T18 based on the boom lowering pilot pressure Pbd input from the pressure sensor 85. Furthermore, a compensation gain is set according to the characteristics of the table T16 based on the boom bottom chamber pressure Pbb input from the pressure sensor 89.

  Further, the compensation gain set according to the specification of the table T16 and the compensation gain set according to the characteristic of the table T18 are compared by the maximum value selector 108 to select a large compensation gain. The compensation gain is multiplied by the multiplier 109 with the pump capacity set according to the characteristics of the table T14. That is, the pump capacity with respect to the arm out operation amount is decreased when the boom lowering operation amount is detected.

  Similarly, the compensation gain set according to the characteristic of the table T16 and the compensation gain set according to the characteristic of the table T17 are compared by the maximum value selector 111 to select a large compensation gain. The compensation gain is multiplied by the multiplier 112 and the pump capacity set according to the characteristics of the table T13.

  The boom pump pump capacity obtained by the multiplier 107 and the arm pump capacity obtained by the multiplier 109 are compared by the maximum value selector 114 to select a larger pump capacity, and the selected pump capacity is Based on the characteristics of the table T19, the pressure is converted to a negative control pressure, and the electromagnetic proportional valve 38R for controlling the main pump 32 is controlled.

  Similarly, the arm pump capacity obtained by the multiplier 112 and the swing pump capacity set by the table T15 are compared by the maximum value selector 115 to select a large pump capacity, and the selected pump capacity is selected from the table T20. Based on this characteristic, the pressure is converted to a negative control pressure, and the electromagnetic proportional valve 38L for controlling the main pump 31 is controlled.

  Therefore, when the working device 13 (FIG. 6) is in the air, that is, when the bucket 23 (FIG. 6) is away from the ground, the boom bottom chamber pressure Pbb is high. A value smaller than the compensation gain set according to the characteristic of T17 is set.

  At this time, due to the characteristics of the table T17, when the boom lowering pilot pressure becomes relatively large, the compensation gain becomes smaller than 1.0.

  Similarly, due to the characteristics of the table T18, when the boom lowering pilot pressure becomes relatively large, the compensation gain becomes smaller than 1.0.

  Therefore, the boom pumping operation amount suppresses the capacity of each arm pump, suppresses the flow rate supplied from the main pumps 31 and 32 to the rod chamber 26r of the arm cylinder 26, and returns oil from the bottom chamber 25b of the boom cylinder 25. Regenerated in the rod chamber 26r of the arm cylinder 26.

  That is, the controller 91 outputs an operation control signal for operating the main pumps 31 and 32 to suppress the flow rate supplied to the arm cylinder 26 when the boom lowering operation amount increases when the boom lowering operation and the arm out operation are combined. Output.

  As described above, the flow rate supplied to the arm cylinder 26 is mostly covered by the regeneration flow rate from the bottom chamber 25b of the boom cylinder 25, and the pump flow rate can be greatly reduced, so that energy efficiency is improved.

(III) Combined operation of boom lowering, arm out and turning In the first control unit 93 shown in FIGS. 1 to 3, in addition to the combined operation of boom lowering and arm out in (II) above, further turning operation is performed. Then, the pilot pressure is set according to the characteristics of the table T1 based on the turning pilot pressure Psw input from the pressure sensor 88. Further, the opening area of the regenerative control valve 52 is set according to the characteristics of the table T2 based on the boom lowering pilot pressure Pbd input from the pressure sensor 85.

  A compensation gain (for example, 0 to 1.0) for adjusting the opening area of the regenerative control valve 52 according to the characteristics of the table T3 based on the arm-out pilot pressure Pao input from the pressure sensor 86 is set. Further, multiplier 101 multiplies the opening area set according to the characteristics of table T2 and the compensation gain set according to the characteristics of table T3.

  Next, based on the opening area of the regeneration control valve 52 obtained by the multiplier 101, a compensation gain (for example, 0 to 1) for adjusting the operation control signal (pilot pressure) of the swing priority valve 53 according to the characteristics of the table T4. .0) is set. Then, the pilot pressure set according to the characteristic of the table T1 and the compensation gain set according to the characteristic of the table T4 are multiplied by the multiplier 102, and the pilot of the electromagnetic proportional valve 78 for controlling the swing priority valve 53 is obtained. Pressure is set.

  Since the turning priority valve 53 has a characteristic that the opening area becomes relatively small when the pilot pressure of the electromagnetic proportional valve 78 becomes relatively large, the turning pilot pressure Psw inputted from the pressure sensor 88 is reduced by the characteristic of the table T1. When the pressure is relatively large, the pilot pressure of the electromagnetic proportional valve 78 is set to a characteristic that relatively decreases.

  On the other hand, the characteristics of the table T4 are such that when the opening area of the regenerative control valve 52 for regenerating the return oil from the bottom chamber 25b of the boom cylinder 25 to the arm cylinder 26 becomes relatively large, the compensation gain becomes smaller than 1.0. Set.

  Therefore, when the boom lowering operation, the arm out operation, and the turning operation are combined, the opening area of the turning priority valve 53 is adjusted according to the flow rate regenerated from the bottom chamber 25b of the boom cylinder 25 to the arm cylinder 26, and the regeneration control is performed. When the opening area of the valve 52 is relatively large and the flow rate regenerated to the arm cylinder 26 is increased, the turning priority valve 53 is throttled to restrict the flow rate flowing to the arm flow control valve 47, and conversely the opening area of the regenerative control valve 52 is When the flow rate regenerated to the arm cylinder 26 is relatively small, the turning priority valve 53 is opened, and the flow rate flowing to the arm flow control valve 47 is increased. That is, the controller 91, when combining the boom lowering operation, the arm out operation, and the turning operation, based on the turning operation amount and the opening of the regenerative control valve 52, that is, the opening area, that is, the opening of the turning priority valve 53, that is, the opening area. An operation control signal for controlling the output is output.

  As a result, the boom flow control valve 45 is controlled to the boom lowering position 45a side according to the boom lowering operation amount, and the boom flow control valve 46 is adjusted to the boom lowering operation amount weighted in the table T8 based on the arm out operation amount. Accordingly, the electromagnetic proportional valve 59 is controlled to the boom lowering position 46a side, and the arm flow control valves 47 and 48 are controlled to the arm out positions 47a and 48a, which are stick-out positions, according to the arm out operation amount. The control valve 49 is controlled based on the turning operation amount. Further, the boom regeneration valve 51 increases the regeneration flow rate from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 25r by the electromagnetic proportional valve 69 in accordance with the boom lowering operation amount weighted in the table T9 based on the arm out operation amount. Controlled by position. Further, the regeneration control valve 52 regenerates from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 26r of the arm cylinder 26 by the electromagnetic proportional valve 73 in accordance with the boom lowering operation amount weighted in the table T3 based on the arm out operation amount. It is controlled to the position where the flow rate is set. Further, the swing priority valve 53 is based on the boom lowering operation amount, the arm out operation amount, and the swing operation amount, that is, the boom lowering operation amount weighted in the table T3 based on the arm out operation amount (opening of the regeneration control valve 52). The electromagnetic proportional valve 78 controls the supply flow rate from the main pump 31 to the rod chamber 26r of the arm cylinder 26 in accordance with the turning operation amount weighted by the table T4.

  For this reason, it is possible to improve the operability when combining the boom lowering operation, the arm out operation, and the turning operation, and to improve the energy efficiency.

(IV) Bucket grounding operation When the bucket 23 (FIG. 6) is grounded, the boom bottom chamber pressure Pbb drops below a predetermined value. In the third control unit 95 shown in FIGS. 1, 2, and 5, a compensation gain is set according to the characteristics of the table T16 based on the boom bottom chamber pressure Pbb input from the pressure sensor 89. At this time, the compensation gain is 1.0 due to the characteristics of the table T16. Accordingly, the outputs of the maximum value selectors 108 and 111 become 1.0, and the pump capacity set by the table T12, the pump capacity set by the table T13, and the pump capacity set by the table T14 are output as they are. .

  Thus, when the boom lowering operation is performed in a state where the bucket 23 is grounded, the pressure oil of the main pump 32 is supplied to the rod chamber 25r of the boom cylinder 25, and the machine body 11 (FIG. 6) of the work machine 10 may be lifted. it can.

  Further, when the boom lowering operation and the arm out operation are combined with the bucket 23 being grounded, pressure oil is supplied from the main pumps 31 and 32 to the rod chamber 25r of the boom cylinder 25 and the rod chamber 26r of the arm cylinder 26, and the bucket With grounding 23, it can be pushed forward to level the ground.

  That is, the controller 91 operates the main pump 32 so as to control the amount of hydraulic oil supplied to the rod chamber 25r of the boom cylinder 25 based on the boom operation amount when the boom bottom chamber pressure Pbb is equal to or less than a predetermined value. A control signal is output, and an operation control signal for operating the main pumps 31 and 32 is output so as to control the amount of hydraulic oil supplied to the rod chamber 26r of the arm cylinder 26 based on at least the arm-out operation amount. In other words, in a state where the bucket 23 is grounded, the restriction on the pump flow rate is released so that the normal operation can be performed.

  Next, effects of the illustrated embodiment will be listed.

  In the boom lowering single operation, it is possible to suppress the increase in the rod chamber pressure of the boom cylinder 25 and perform the same control as the conventional boom regeneration control for regenerating the hydraulic oil from the bottom chamber 25b of the boom cylinder 25 to the rod chamber 25r. It is possible to perform a boom lowering operation that suppresses energy loss by suppressing the pump pressure and the pump flow rate when the boom is lowered.

  For example, in the combined operation of the boom lowering operation and the arm out operation with the bucket 23 in the air, the boom bottom chamber pressure Pbb is increased so that the return oil from the bottom chamber 25b of the boom cylinder 25 can be regenerated to the arm cylinder 26. In addition, by adjusting the opening of the regenerative control valve 52 and the pump capacity according to the boom lowering operation amount and the arm out operation amount, it becomes possible to increase the regeneration flow rate to the arm cylinder 26 and reduce the pump flow rate. , Energy efficiency can be greatly improved. Further, since the regeneration control valve 52 and the pump capacity are adjusted according to the boom lowering operation amount and the arm out operation amount, the normal control can be smoothly shifted to the regeneration control.

  When the boom lowering operation, the arm out operation, and the turning operation are combined, the flow rate supplied to the turning motor 18 flows into the rod chamber 26r of the arm cylinder 26, and the rod chamber of the arm cylinder 26 from the bottom chamber 25b of the boom cylinder 25 Since the opening degree of the swing priority valve 53 is adjusted so that the regeneration flow rate flowing through the 26r does not decrease, operability can be ensured and energy efficiency can be improved.

  Further, since the grounding of the bucket 23 is determined based on the boom bottom chamber pressure Pbb, when the boom bottom chamber pressure Pbb is less than a predetermined value such as the grounding of the working device 13, that is, the grounding of the bucket 23, the rod chamber 25r of the boom cylinder 25. Since the amount of hydraulic oil supplied to the cylinder is controlled and the amount of hydraulic oil from the main pumps 31, 32 to the rod chamber 26r of the arm cylinder 26 is controlled based on at least the arm-out operation amount, the work device 13 (bucket 23) is ungrounded. It is possible to quickly and smoothly shift from the operation in the state to the operation in the grounding state of the bucket 23 or the like.

  INDUSTRIAL APPLICABILITY The present invention has industrial applicability to operators that manufacture and sell a control device that controls regeneration of return oil from the bottom chamber of a boom cylinder and a work machine equipped with this control device.

T tank
10 work machines
11 Airframe
13 Working device
15 Undercarriage
16 Upper swing body
18 slewing motor
21 Boom
22 Arm that is a stick
25 Boom cylinder
25b Bottom chamber
25r rod chamber
26 Arm cylinder which is a stick cylinder
31, 32 Fluid pressure pump main pump
33 engine
46 Boom flow control valve, which is a flow control valve
51 Boom regeneration valve
52 Regenerative control valve
53 Rotation priority valve
81 Boom remote control valve as a control body for boom
82 Arm remote control valve as stick operating body
83 Swing remote control valve as swivel control
85 Pressure sensor as means for detecting the amount of boom lowering operation
86 Pressure sensor as a means to detect stick-out manipulated variable
88 Pressure sensor as means for detecting turning operation amount
89 Pressure sensor as bottom chamber pressure detection means
91 controller

Claims (3)

A work apparatus including at least a body, a boom that is axially connected to the body so as to be movable up and down, and a stick that is axially connected to the boom so as to be able to rotate in and out of the boom, and mounted on the body An engine, a variable displacement fluid pressure pump mounted on the fuselage and operated by the engine to discharge a working fluid, a boom operation body for operating the boom, a stick operation body for operating the stick, and a fluid A control device for a work machine comprising: a boom cylinder that is operated by a working fluid discharged from a pressure pump and rotates a boom; and a stick cylinder that is operated by a working fluid discharged from a fluid pressure pump and rotates a stick. And
A boom lowering operation amount detection means for detecting a boom lowering operation amount by the boom operating body;
A stick-out operation amount detection means for detecting a stick-out operation amount by an operating body for a stick;
Bottom chamber pressure detection means for detecting the bottom chamber pressure of the boom cylinder;
A boom regeneration valve that regenerates the working fluid from the bottom chamber of the boom cylinder to the rod chamber;
A flow control valve for guiding the return fluid from the bottom chamber of the boom cylinder to the tank;
A regenerative control valve that supplies part of the return fluid in the bottom chamber of the boom cylinder to the stick cylinder;
Detection of boom lowering operation amount detection means, stick-out operation amount detection means, and bottom chamber pressure detection means is input, respectively, and at least a boom regeneration valve, a flow control valve, a regenerative control valve, and A controller for outputting each operation control signal of the fluid pressure pump,
The controller individually operates the boom regeneration valve and the flow control valve so as to regenerate the working fluid from the bottom chamber of the boom cylinder to the rod chamber while suppressing the boom chamber rod chamber pressure increase during the boom lowering operation alone. Output operation control signal,
An operation control signal for individually operating the boom regeneration valve and the flow control valve so as to increase the bottom chamber pressure of the boom cylinder based on the boom operation amount and the stick-out operation amount when the boom lowering operation and the stick-out operation are combined. Is output, and an operation control signal for controlling the opening of the regenerative control valve is output based on the boom operation amount and the stick-out operation amount, and the flow supplied to the stick cylinder is suppressed by increasing the boom lowering operation amount. An operation control signal for operating the fluid pressure pump is output. The work machine includes a lower traveling body and an upper revolving body provided on the lower traveling body so as to be able to swivel in the airframe, and a turning operation body for turning operation of the upper revolving body and a discharge from a fluid pressure pump. A swing motor that is operated by the working fluid and rotates the upper swing body,
A turning operation amount detection means for detecting a turning operation amount of the upper turning body by the turning operation body;
A turning priority valve for limiting the amount of working fluid supplied to the stick cylinder when the stick operation and the turning operation are combined,
The controller receives detection of boom lowering operation amount detection means, stick-out operation amount detection means, bottom chamber pressure detection means, and turning operation amount detection means, respectively. Based on these detections, at least a boom regeneration valve, a flow control valve, Output the operation control signals for the regenerative control valve, swivel priority valve, and fluid pressure pump,
The operation control signal for controlling the opening degree of the turning priority valve based on the turning operation amount and the opening degree of the regenerative control valve is output when the boom lowering operation, the stick-out operation, and the turning operation are combined. 1. A control device for a work machine according to 1. The controller outputs an operation control signal for operating the fluid pressure pump to control the amount of working fluid supplied to the rod chamber of the boom cylinder based on the boom operation amount when the bottom chamber pressure of the boom cylinder is equal to or less than a predetermined value. And an operation control signal for operating the fluid pressure pump so as to control the amount of working fluid supplied to the rod chamber of the arm cylinder based on at least the stick-out operation amount. Work machine control device.

Images