JP2015034617A - Pump confluence circuit, and work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump confluence circuit for making a plurality of pump flow rates confluent, in which the reduction of a total pump flow rate under a heavy load can be properly improved in accordance with the load fluctuation from a low load time to a high load time.SOLUTION: A confluence valve 36 is switched between a confluence state, in which the working oil to be discharged from a third pump P3 is made confluent with the working oil to be discharged from a first pump P1 and a second pump P2, and a confluence released state, in which the confluence state of the working oil to be discharged from the third pump P3 is released for the drain. A pressure sensor 38 detects the discharge pressure of the second pump P2 thereby to detect the load pressure of the hydraulic load to be applied to a work device containing a forestry harvester. The control means 41 controls the confluence valve 36 into the confluence state, in the case where the load pressure detected by the pressure sensor 38 is lower than a threshold value, and controls the confluence valve 36 into the confluent release state, in the case where said load pressure rises to a level higher than the threshold value.

Description

  The present invention relates to a pump merging circuit for merging a plurality of pump discharge flow rates and a work machine using the pump merging circuit.

  As a pump merging circuit for merging a plurality of pump discharge flow rates, three pumps can be combined into one pump, or two pumps or three pumps can be combined according to a combination of existing pumps and control valves provided in a work machine such as a hydraulic excavator. There is a combination that is selected by a selection unit and corresponds to the required flow rate of various attachments (see, for example, Patent Document 1).

  For example, a forestry machine equipped with a harvester, which is a forestry-specific work attachment, instead of a bucket in a conventional excavator needs to supply a sufficient flow rate to the harvester when using this harvester. The flow rate discharged from the sub-third pump is added to the flow rate discharged from the first pump and the second pump, and the hydraulic oil discharged from the three hydraulic pumps is merged and supplied to the harvester.

JP 2004-245262 A

  However, when the load of the harvester increases and the pressure of the working pressure oil rises, the pump load acting on the three hydraulic pumps of the first pump, the second pump, and the third pump also increases, and the first pump and the first pump from the engine increase. When the input torque to the two pumps is reduced and the discharge flow rates of the first pump and the second pump are extremely reduced, the hydraulic oil discharged from the three hydraulic pumps is combined and supplied at high load. However, rather than the case where the hydraulic oil discharged from the two hydraulic pumps of the first pump and the second pump is fed together and supplied, the supply flow rate to the harvester is reduced and the operation speed of the harvester is reduced. Sometimes.

  Further, the selection means is manually operated (pedal operation or switch operation) by an operator of the forestry specification machine, and there is a problem that appropriate switching cannot be performed according to the load fluctuation.

  The present invention has been made in view of the above points, and in a pump merging circuit for merging a plurality of pump flow rates, a decrease in the total pump flow rate at a high load is caused by a load fluctuation from a low load to a high load. It is an object of the present invention to provide a pump merging circuit that can be improved appropriately according to the above and a work machine using the pump merging circuit.

  According to the first aspect of the present invention, the working fluid discharged from the sub pump driven by the engine is joined to the working fluid discharged from the main pump driven by the engine, and is supplied to the fluid pressure actuator. A merging circuit, a merging state in which the working fluid discharged from the sub-pump merges with the working fluid discharged from the main pump, and a merging release state in which the merging state of the working fluid discharged from the sub-pump is released and drained. The merging valve to be switched, the pressure sensor that detects the load pressure by detecting the discharge pressure of the main pump, and the merging valve is released from the merging state when the load pressure detected by the pressure sensor rises above the threshold value It is a pump junction circuit provided with the control means provided with the function to control to a state.

  According to a second aspect of the present invention, the merging valve in the pump merging circuit according to the first aspect is a pilot operated switching valve capable of switching between a merging state and a merging release state by a pilot pressure. The pilot pressure is supplied to the merging valve to control the merging valve to the merging state, and the pilot pressure switching solenoid valve that discharges the pilot pressure to the merging valve and controls the merging valve to be in the merging release state is detected by the pressure sensor. It is discriminated whether the applied load pressure is lower or higher than a threshold value, and when the load pressure is high, the pilot pressure switching electromagnetic valve is provided with an electromagnetic valve control unit that outputs an electric signal for releasing the merge.

  The invention described in claim 3 includes a hydraulically driven machine body and a hydraulically driven work device mounted on the machine body, and the work apparatus operates from the pump junction circuit according to claim 1 or 2. It is a work machine provided with an attachment that is operated by a hydraulic actuator that is supplied with oil.

  According to a fourth aspect of the present invention, an engine, a first pump and a second pump as a main pump, and a third pump as a sub pump are mounted on the machine body of the work machine according to the third aspect. The attachment of the forestry harvester, the control means of the pump confluence circuit, when the load pressure of the hydraulic load applied to the various hydraulic actuators of the work equipment including the fuselage and the forestry harvester detected by the pressure sensor is lower than the threshold, The hydraulic oil discharged from the first pump and the second pump is supplied to various hydraulic actuators of the working apparatus including the fuselage and the forestry harvester, and the hydraulic oil discharged from the third pump is supplied to the hydraulic actuator of the forestry harvester by the merge valve. When the load pressure of the hydraulic load is higher than the threshold value, the operation discharged from the third pump is performed. The merging state of the oil released by the confluence valve, those having a function of supplying the working oil discharged from the first pump and the second pump only to various hydraulic actuators of the working device comprising a body and a forestry harvester.

  According to the first aspect of the present invention, when the load pressure detected by the pressure sensor is lower than the threshold, the control means joins the working fluid discharged from the main pump to the working fluid discharged from the main pump. Since the valve is controlled to be in the merged state, a sufficient flow rate can be supplied to the fluid pressure actuator to ensure sufficient actuator speed, and when the load sensor rises above the threshold and the pressure sensor detects The control means automatically controls the merging valve to the merging release state so that the merging state of the working fluid discharged from the sub pump is released and drained, so that the load divided from the engine to the sub pump is eliminated. The driving torque input to the main pump increases from the time when the sub pump flow rate merges, and the main pump discharge flow rate from the time when the sub pump flow rate merges Therefore, in the pump merging circuit that merges multiple pump flow rates, the decrease in the total pump flow rate at high load should be adjusted appropriately according to the load fluctuation from low load to high load. It is possible to further suppress the speed reduction of the fluid pressure actuator, and to improve the sub-pump flow rate merging.

  According to the second aspect of the present invention, when the load pressure detected by the pressure sensor is higher than the threshold, the pilot pressure switching electromagnetic valve having excellent responsiveness is joined by the electrical signal output from the electromagnetic valve control unit. Since the merging valve, which is a pilot operated switching valve suitable for flow rate control, is controlled to the release command position and the merging valve is released, when the load pressure becomes higher than the threshold value, the discharge flow rate from the main pump and sub pump is reduced to the main flow rate. The discharge flow rate of only the pump can be switched at an appropriate timing.

  According to a third aspect of the present invention, the hydraulically driven working device mounted on the hydraulically driven machine body is attached by a hydraulic actuator that receives the supply of hydraulic oil from the pump junction circuit according to the first or second aspect. In a work machine equipped with a sub-pump flow rate merging, the sub-pump flow rate merging state is canceled appropriately according to the load fluctuation from low load to high load. Since it can be suppressed, the speed reduction of the hydraulic actuator can be improved compared to when the sub-pump flow rate is merged, and the working efficiency by the hydraulic drive attachment can be improved compared to when the sub-pump flow rate is merged.

  When the hydraulic oil discharged from the third pump is joined to the hydraulic oil discharged from the first pump and the second pump by the merging valve and supplied to the forestry harvester, By appropriately canceling the merge state of the third pump flow rate according to the load fluctuation from the low load to the high load, it is possible to suppress the decrease in the total pump flow rate at the time of the high load than at the time of the third pump flow rate merge. In addition, the work speed reduction of the hydraulic drive type forestry harvester can be improved from the time when the third pump flow rate is merged, and the work efficiency of felling timber work by the forestry harvester can be improved compared to the time when the third pump flow rate is merged.

It is a circuit diagram showing one embodiment of a pump confluence circuit concerning the present invention. It is a circuit diagram which shows the example of pump installation of a merging circuit same as the above. It is a circuit diagram which shows an example of the merge valve of a merge circuit same as the above. It is a characteristic view which shows the pressure and the flow characteristic of a merge circuit same as the above. It is a side view which shows one Embodiment of the working machine provided with the same merge circuit same as the above.

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

  FIG. 5 shows a forestry specification machine 11 based on a hydraulic excavator as a work machine. The forestry specification machine 11 includes a hydraulically driven machine body 12 and a hydraulically driven working device mounted on the machine body 12. 13 and.

  The machine body 12 is provided on the lower traveling body 14 so that an upper swing body 16 can swing via a swing bearing portion 15. The upper swing body 16 is equipped with a cab 17 that forms an operator's cab and a machine room 18. In the machine room 18, the engine 19 shown in FIG. 2, the first pump P1 and the second pump P2 as the main pump, the third pump P3 as the sub pump, and the pilot pump Pp are mounted. ing.

  The working device 13 includes a boom 21 that is pivotally supported by the upper swing body 16 and rotated by a boom cylinder 21c, an arm 22 that is axially connected to the tip of the boom 21 and rotated by an arm cylinder 22c, and the arm 22 And a forestry harvester 23 as an attachment that is attached to a member that is pivotally connected to the tip of the shaft and rotated by a bucket cylinder 23c.

  As shown in FIG. 1, the first pump P1 and the second pump P2 supply hydraulic oil as a working fluid to the control valve 24, and the control valve 24 is slidably provided therein. In addition, a spool (not shown) for controlling various hydraulic actuators is provided, and the hydraulic oil supplied from the first pump P1 and the second pump P2 is subjected to direction control and flow rate control, and various hydraulic actuator circuits (not shown). ) Includes left and right traveling hydraulic motors (not shown) provided on the lower traveling body 14 of the airframe 12, a turning hydraulic motor (not shown) for driving the upper turning body 16 to rotate, and a forestry harvester 23. This is supplied to various hydraulic actuators such as the boom cylinder 21c of the work device 13. In FIG. 1, only the hydraulic actuator circuit for the forestry harvester 23 is shown, and the other hydraulic actuator circuits are omitted.

  The various spools in the control valve 24 were adjusted to reduce the pressure of the pilot primary pressure oil supplied from the pilot pump Pp via the solenoid valve 25 for hydraulic lock by a manual pilot operation valve 26 for controlling various hydraulic actuators. Displacement is controlled by pilot secondary pressure oil.

  The solenoid valve 25 for the hydraulic lock is turned on (pilot primary pressure oil supply state) by the unlocking operation of the hydraulic lock lever or the like by the operator in the cab 17, and the manual pilot operated valve 26 is the pilot primary pressure. Is reduced to the pilot secondary pressure corresponding to the lever operation or pedal operation by the operator and output. Further, the pilot pressure oil taken out from the pilot pump Pp through the other electromagnetic valve 27 is supplied to another pilot circuit.

  The forestry harvester 23 is operated by a hydraulic actuator 32 as a fluid pressure actuator that receives supply of hydraulic oil from the pump confluence circuit 31 shown in FIG. 1. They are a hydraulic motor that drives a saw for cutting and a material feed roller for debriding, and a hydraulic cylinder for opening and closing a grapple that grips the material. A description of the return oil circuit from the hydraulic actuator 32 is omitted.

  As shown in FIG. 2, the first pump P1 and the second pump P2 are variable displacement pumps that are controlled so as to decrease the discharge flow rate in accordance with an increase in the pump discharge pressure or the load pressure. Compared with the three pumps P3 and the pilot pumps Pp, the capacity can be variably controlled. The third pump P3 functions as an auxiliary pump for the first pump P1 and the second pump P2, and the pilot pump Pp is a pilot pressure that supplies a pilot pressure for piloting a spool that is a movable valve body of various valves. Is the source.

  The first pump P1 is directly driven by the engine 19, the pilot pump Pp is driven by the engine 19 via the first pump P1, the second pump P2 is driven by the engine 19 via the gear 33, and the third The pump P3 is driven by the engine 19 via the gear 33 and the second pump P2, and both discharge hydraulic oil sucked from the tank T.

  The pump junction circuit 31 shown in FIG. 1 is driven by the engine 19 to hydraulic fluid supplied from the first pump P1 and the second pump P2 driven by the engine 19 via the control valve 24 and the main passage 34. This is an electric / hydraulic circuit that combines the hydraulic oil supplied from the third pump P3 and supplies it to the hydraulic actuator 32 of the forestry harvester 23.

  In the pump junction circuit 31, a junction valve 36 and a check valve 37 for preventing backflow are installed in the discharge passage 35 from the third pump P3.

  The merging valve 36 joins the hydraulic oil discharged from the third pump P3 to the hydraulic oil supplied through the main passage 34 or releases the merging state. 3, the pilot-operated switching valve is capable of switching between the merged position 36A and the merge-released position 36B depending on the presence or absence of the pilot pressure. In the merged position 36A, the first pump P1 And a passage 36a that joins the hydraulic oil discharged from the third pump P3 to the hydraulic oil discharged from the second pump P2, and the operation discharged from the third pump P3 at the position 36B in the merge-release state. A passage 36b for releasing the joined state of oil and draining the tank T is provided.

  In the discharge passage of the main pump (for example, the second pump P2), by detecting the discharge pressure of the second pump P2, the hydraulic motor for turning the body 12 that receives the hydraulic oil supply from the second pump P2, etc. and forestry There is provided a pressure sensor 38 for detecting the load pressure of the hydraulic load applied to the various hydraulic actuators of the working device 13 including the hydraulic actuator 32 of the harvester 23.

  The pressure sensor 38 detects the discharge pressure of the second pump P2, and controls the merging valve 36 for merging / releasing the discharge flow rate from the third pump P3 according to the load condition of the second pump P2. This pressure sensor 38 converts a displacement amount of a diaphragm or the like that is displaced by a change in hydraulic pressure into a change in an electric amount such as an electric resistance value or a capacitance, and outputs the change. A pressure switch that operates at a constant hydraulic pressure is also included in the pressure sensor 38.

  Further, the pump confluence circuit 31 shown in FIG. 1 has a function of controlling the confluence valve 36 from the confluence state to the confluence release state when the load pressure detected by the pressure sensor 38 rises to a value higher than the threshold value. The control means 41 is provided.

  As shown in FIG. 1, the control means 41 supplies pilot pressure to the pilot pressure operating portion 36c of the merging valve 36 to control the merging valve 36 to a position 36A in the merging state, and also controls the pilot pressure with respect to the merging valve 36. The pilot pressure switching solenoid valve 42 that controls the return of the merging valve 36 to the position 36B in the merging release state, and whether the load pressure detected by the pressure sensor 38 is lower or higher than the threshold is determined. Is higher than the threshold value, the solenoid valve controller 43 outputs an electrical signal for releasing the merging to the pilot pressure switching solenoid valve 42.

  The pilot pressure switching electromagnetic valve 42 has a merging command position 42A for controlling the merging valve 36 to a merging position 36A, and a merging release command position 42B for controlling the merging valve 36 to a merging canceling position 36B. The merge command position 42A of the pilot pressure switching electromagnetic valve 42 includes a passage 42a for communicating the pilot pressure oil from the pilot pump Pp to the pilot pressure operating portion 36c of the merge valve 36, and the merge release command position 42B is The pilot pressure oil from the pilot pump Pp is shut off, and a passage 42b for returning the pilot pressure oil acting on the merging valve 36 to the tank T is provided.

  The solenoid valve control unit 43 measures and displays voltage / current signals, etc., and determines whether the load pressure is lower or higher than the threshold value, and pilot pressure switching based on the determination signal output from the panel meter 44. And a relay 45 that outputs a solenoid driving signal to the electromagnetic valve. An in-vehicle battery 46 is connected to the panel meter 44 via a switch 47 installed in the cab 17.

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

The control means 41 of the pump confluence circuit 31 is a hydraulic load of the second pump P2 detected by the pressure sensor 38, that is, various hydraulic pressures of the working device 13 including the turning hydraulic motor of the airframe 12 and the hydraulic actuator 32 of the forestry harvester 23. When the load pressure of the hydraulic load applied to the actuator is lower than a threshold value (for example, 150 kg / cm ^{2 in} FIG. 4), the pilot pressure switching electromagnetic valve 42 is controlled to the merging command position 42A shown in FIG. 36 is also controlled to the merged position 36A shown in FIG. 3, so that the hydraulic oil discharged from the first pump P1 and the second pump P2 can be used for various types of working devices 13 including the fuselage 12 and the forestry harvester 23. In addition to being supplied to the hydraulic actuator, the hydraulic oil discharged from the third pump P3 and passed through the merging valve 36 is supplied to the hydraulic actuator 32 of the forestry harvester 23. Therefore, the total flow rate of the pump as a whole is increased by the hatched portion shown in FIG. 4 from the time when the first pump P1 and the second pump P2 alone are combined. Therefore, the operating speed of the forestry harvester 23 is two pumps combined. It is faster than time.

  Further, when the load pressure of the hydraulic load detected by the pressure sensor 38 is higher than the threshold value, the pilot pressure switching electromagnetic valve 42 is controlled to the merging release command position 42B, so that the merging valve 36 is also in the position 36B in the merging release state. Therefore, the merging state of the hydraulic oil discharged from the third pump P3 is released by the merging valve 36, and only the hydraulic oil discharged from the first pump P1 and the second pump P2 is swiveled. To the various hydraulic actuators of the working device 13 including the hydraulic actuator 32 for the forestry harvester 23 and the like.

  That is, by detecting the discharge pressure of the second pump P2 by the pressure sensor 38, the load pressure of the hydraulic load is detected. When this load pressure is higher than the threshold value, the solenoid valve control unit 43 controls the pilot pressure switching electromagnetic By switching the valve 42 from the merging command position 42A to the merging release command position 42B, the pilot pressure is discharged from the pilot pressure acting part 36c of the merging valve 36, and the spool of the merging valve 36 is released from the merging position 36A. Since the hydraulic oil discharged from the third pump P3 is drained to the tank T and the merge from the third pump P3 is released by switching to the position 36B by the spring return action, the first pump P1 and the second pump The operation is switched to the supply of pressure oil to various hydraulic actuators of the working device 13 including the machine body 12 and the forestry harvester 23 only by the merge of the two pumps P2.

  As described above, when the engine load is high, the engine load of the third pump P3 disappears, and accordingly, the input torque from the engine 19 to the first pump P1 and the second pump P2 increases compared to the time when the three pumps merge. The total flow rate of the pump increases only by the mesh area shown in Fig. 4 compared to when the three pumps are combined at high load, so the operating speed of the hydraulic actuator 32 of the forestry harvester 23 is faster than when the three pumps are combined at high load. Is done.

  Next, effects of the illustrated embodiment will be described.

  When the load pressure detected by the pressure sensor 38 is lower than the threshold value, the control means 41 adds the hydraulic oil discharged from the third pump P3 to the hydraulic oil discharged from the first pump P1 and the second pump P2. Automatically controls the merge valve 36 to the merged position 36A, so that a sufficient flow rate can be supplied to the hydraulic actuator 32 of the forestry harvester 23 to ensure a sufficient actuator speed.

  Further, when the pressure sensor 38 detects a state where the load pressure increases and is higher than the threshold value, the control means 41 releases the joined state of the hydraulic oil discharged from the third pump P3 and drains it. Since the merging valve 36 is automatically controlled to the position 36B in the merging release state, the load from the engine 19 to the third pump P3 is eliminated, and the engine 19 inputs the first pump P1 and the second pump P2. Since the driving torque increases from the time when the third pump flow rate merges and the discharge flow rates of the first pump P1 and the second pump P2 recover from the time when the third pump flow rate merges, The decrease in the total pump flow rate at high load can be suppressed more appropriately than at the time of the 3rd pump flow rate merge according to the load fluctuation from low load to high load, and the speed of the hydraulic actuator 32 of the forestry harvester 23 The drop can be improved compared with the case of the third pump flow rate merge.

  In short, if the load pressure detected by the pressure sensor 38 is higher than the threshold value, the electrical pressure signal output from the relay 45 of the solenoid valve control unit 43 causes the pilot pressure switching solenoid valve 42 having excellent responsiveness to be released. Since the merging valve 36, which is a pilot operated switching valve suitable for flow rate control, is controlled to the position 42B and the merging release operation is performed, when the load pressure becomes higher than the threshold value, the first pump P1 and the second pump P2 The three pump discharge flow rate from the third pump P3 can be switched to the two pump discharge flow rate of the first pump P1 and the second pump P2 at an appropriate timing.

  Thus, the forestry specification machine equipped with the forestry harvester 23 in which the hydraulically driven working device 13 mounted on the hydraulically driven machine body 12 is operated by the hydraulic actuator 32 that receives the supply of hydraulic oil from the pump junction circuit 31. When the hydraulic oil discharged from the first pump P1 and the second pump P2 is combined with the hydraulic oil discharged from the third pump P3 by the merging valve 36 and supplied to the forestry harvester 23 in FIG. By properly canceling the merge state of the third pump flow rate according to the load fluctuation from the time to the high load, the decrease in the total pump flow rate at the high load can be suppressed from the time of the third pump flow rate merge. The work speed reduction of the hydraulic actuator 32 of the hydraulic harvester 23 can be improved compared to the time when the third pump flow rate is merged, and the work efficiency of felling timber work by the hydraulically driven forestry harvester 23 is better than when the third pump flow rate is merged I can go up.

  Next, another embodiment not shown will be described.

  The pilot pressure switching solenoid valve 42 of the illustrated embodiment is of an on / off operation type by a relay 45, but a plurality of stages from the panel meter 44 according to an increase in load pressure detected by the pressure sensor 38. By allowing an electric signal to be output to the electromagnetic valve 42, the electromagnetic valve 42 and the merging valve 36 can be of a proportional operation type.

  In the case of this proportional operation type, the spool of the pilot pressure switching solenoid valve 42 is proportionally displaced from the merging command position 42A to the merging release command position 42B in accordance with an increase in the load pressure detected by the pressure sensor 38. Thus, the pilot hydraulic pressure output from the solenoid valve 42 is proportionally reduced in accordance with the increase in the load pressure, and the spool of the merging valve 36 is increased from the position 36A in the merging state by the pilot hydraulic pressure in accordance with the increase in the load pressure. By proportionally shifting to the position 36B in the merge release state, it is possible to control to gradually decrease the flow rate merged from the third pump P3 into the main passage 34 from the maximum to zero.

  The present invention has industrial applicability to business operators involved in manufacturing pump confluence circuits or work machines.

P1 1st pump as main pump P2 2nd pump as main pump P3 3rd pump as sub pump
11 Forestry machine as a working machine
12 Airframe
13 Working device
19 engine
23 Forestry harvester as an attachment
31 Pump junction circuit
32 Hydraulic actuators as fluid pressure actuators
36 Joint valve
38 Pressure sensor
41 Control means
42 Solenoid valve for switching pilot pressure
43 Solenoid valve controller

Claims (4)

A pump merging circuit for joining a working fluid discharged from a sub pump driven by the engine to a working fluid discharged from a main pump driven by the engine and supplying the working fluid to a fluid pressure actuator;
A merging valve that switches between a merging state in which the working fluid discharged from the sub pump merges with the working fluid discharged from the main pump and a merging release state in which the merging state of the working fluid discharged from the sub pump is released and drained;
A pressure sensor that detects the load pressure by detecting the discharge pressure of the main pump;
And a control means having a function of controlling the merging valve from the merging state to the merging release state when the load pressure detected by the pressure sensor rises to a value higher than the threshold value. The merging valve is a pilot operated switching valve capable of switching between a merging state and a merging release state by pilot pressure,
The control means
A pilot pressure switching solenoid valve for supplying a pilot pressure to the merging valve to control the merging valve to a merging state, and discharging a pilot pressure for the merging valve to control the merging valve to a merging release state;
A solenoid valve controller that determines whether the load pressure detected by the pressure sensor is lower or higher than a threshold value, and outputs an electrical signal for releasing the merge to the pilot pressure switching solenoid valve when the load pressure is high. The pump confluence circuit according to claim 1. Hydraulically driven aircraft,
A hydraulically driven working device mounted on the fuselage,
Work equipment
A work machine comprising an attachment that is operated by a hydraulic actuator that receives supply of hydraulic oil from the pump junction circuit according to claim 1. The aircraft is equipped with an engine, a first pump and a second pump as main pumps, and a third pump as a sub pump,
The work equipment attachment is a forestry harvester,
The control means of the pump confluence circuit is discharged from the first pump and the second pump when the load pressure of the hydraulic load applied to the various hydraulic actuators of the working device including the machine body and the forestry harvester detected by the pressure sensor is lower than the threshold value. The hydraulic oil is supplied to various hydraulic actuators of the working equipment including the fuselage and the forestry harvester, and the hydraulic oil discharged from the third pump is supplied to the hydraulic actuator of the forestry harvester by the merging valve. Is higher than the threshold value, the joining state of the working oil discharged from the third pump is canceled by the joining valve, and only the working oil discharged from the first pump and the second pump is used as the working device including the fuselage and the forestry harvester. The working machine according to claim 3, further comprising a function of supplying the hydraulic actuators.

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