Hydraulic system and working machine

Abstract

To suppress generation of impact and deterioration of responsiveness when starting or stopping an attachment attached to a working machine.SOLUTION: A hydraulic system includes a control valve configured to adjust a flow rate and a pressure of hydraulic oil supplied to a hydraulic actuator configured to operate an attachment attached to a work machine, and a control device configured to control an opening degree of the control valve by changing an input current value input to the control valve, wherein the control device is configured to gradually change the input current value within a first current range in which the attachment operates when the input current value is changed to a target current value corresponding to a target opening degree of the control valve to start or stop the attachment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work machine and a hydraulic system for starting or stopping an attachment attached to the work machine. [Background technology]

[0002] Work machines such as skid steer loaders and compact track loaders perform work using a work device equipped on the work machine and an attachment attached to the work device while the machine is traveling or stopped. To accomplish this, the work machine is equipped with a hydraulic system, such as that disclosed in Patent Document 1. The hydraulic system includes a control valve that adjusts the flow rate and pressure of hydraulic oil supplied to a hydraulic actuator that operates the attachment, and a control device that controls the aperture of the control valve by varying the current input to the control valve, which is constituted by an electromagnetic proportional valve or the like. The hydraulic actuator and the attachment are activated when the control valve opens and hydraulic oil is supplied to the hydraulic actuator via the control valve. The hydraulic actuator and the attachment are stopped when the control valve closes and hydraulic oil is no longer supplied to the hydraulic actuator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-65999 Summary of the Invention [Problem to be solved by the invention]

[0004] When starting or stopping an attachment, there is a concern that hydraulic oil may suddenly flow into or stop flowing from the hydraulic actuator, causing the attachment to suddenly start or stop, resulting in a large shock (vibration) being applied to the attachment. One possible solution to this problem is to control the opening of the control valve so that hydraulic oil flows into or stops flowing slowly from the hydraulic actuator, but this raises concerns that the time it takes for the attachment to start or stop will be delayed, reducing responsiveness.

[0005] In view of the above problems, an object of the present invention is to suppress the occurrence of shocks and the decrease in responsiveness when starting or stopping an attachment attached to a work machine. [Means for solving the problem]

[0006] A hydraulic system according to one aspect of the present invention includes a control valve that adjusts the flow rate and pressure of hydraulic oil supplied to a hydraulic actuator that operates an attachment attached to a work machine, and a control device that controls the aperture of the control valve by changing the input current value input to the control valve, wherein the control device changes the input current value to a target current value corresponding to a target aperture of the control valve, and gradually changes the input current value within a first current range in which the attachment operates when starting or stopping the attachment.A work machine according to one aspect of the present invention includes a coupling device that couples an attachment, and the hydraulic system. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the occurrence of shocks and the deterioration of responsiveness when starting or stopping an attachment attached to a work machine. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing an example of a hydraulic circuit of a hydraulic system of a work machine. [Figure 2] FIG. 2 is a diagram illustrating an example of an electrical configuration of a hydraulic system of a work machine. [Figure 3] FIG. 10 is a diagram showing an example of control data of an attachment. [Figure 4] FIG. 4 is a diagram showing an example of a change in the input current value to an AUX electromagnetic control valve. [Figure 5] 10 is a flowchart illustrating an example of an attachment use process. [Figure 6] 10 is a diagram showing another example of a change in the input current value to the AUX electromagnetic control valve. FIG. [Figure 7] 10 is a diagram showing another example of a change in the input current value to the AUX electromagnetic control valve. FIG. [Figure 8] 10 is a diagram showing another example of a change in the input current value to the AUX electromagnetic control valve. FIG. [Figure 9] FIG. 10 is a diagram showing the relationship between the rotation speed of a prime mover and the slope of a ramp function. [Figure 10] FIG. 4 is a diagram showing the relationship between the temperature of hydraulic oil of a work machine and the slope of a ramp function. [Figure 11] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings. Fig. 11 shows a side view of a work machine 1 according to an embodiment of the present invention. In this embodiment, a compact track loader is shown as an example of the work machine 1. Note that the work machine according to the present invention is not limited to a compact track loader, and may be, for example, another loader work machine such as a skid steer loader, or a work machine other than a loader work machine.

[0010] The work machine 1 comprises a body 2, a cabin 3, a work device 4, a traveling device 5, and a prime mover 6. The cabin 3 is mounted on top of the body 2. A driver's seat 8 is provided inside the cabin 3. The prime mover 6 is provided at the rear of the body 2. The prime mover 6 is the power source for the work machine 1. In this embodiment, the prime mover 6 is a diesel engine, but it may be another internal combustion engine (engine) such as a gasoline engine, or may be an electric motor such as an electric motor.

[0011] Traveling devices 5 are provided on the left and right sides of the machine body 2. That is, a pair of traveling devices 5 are provided on the left and right sides. The pair of left and right traveling devices 5 support the machine body 2 so that it can travel. In this embodiment, a crawler-type traveling device is exemplified as the traveling device 5, but other than this, it may also be a wheeled traveling device having front wheels and rear wheels, or a semi-crawler-type traveling device.

[0012] The working device 4 is provided to extend forward of the machine body 2. The working device 4 has a boom 10, a first link 12, a second link 13, a lift cylinder 14, and a tilt cylinder 15. The lift cylinder 14 and the tilt cylinder 15 are hydraulic cylinders (hydraulic actuators).

[0013] The booms 10 are provided on the left and right sides of the cabin 3 so as to be able to swing up and down. The front end 10a of the left boom 10 and the front end 10a of the right boom 10 are connected by an irregularly shaped connecting pipe. The rear end 10b of the left boom 10 and the rear end 10b of the right boom 10 are connected by a circular connecting pipe. The first link 12, the second link 13, the lift cylinder 14, and the tilt cylinder 15 are provided on the left and right sides of the machine body 2, corresponding to the left boom 10 and the right boom 10, respectively. The first link 12 and the second link 13 support the rear end 10b of the boom 10 so as to be able to swing up and down.

[0014] More specifically, the first link 12 is provided vertically at the rear end 10b of the boom 10. The upper end 12a of the first link 12 is pivoted to the rear end 10b of the boom 10 via a pivot shaft 16 so as to be rotatable about a horizontal axis. The pivot shaft 16 passes through the rear of a bracket 10k attached to the rear of the boom 10. The lower end 12b of the first link 12 is pivoted to the rear of the machine body 2 via a pivot shaft 17 so as to be rotatable about a horizontal axis. The pivot shaft 17 is provided at the upper rear of the machine body 2.

[0015] The second link 13 is provided in front of the first link 12. A front end 13a of the second link 13 is pivoted by a pivot shaft 20 so as to be rotatable about a horizontal axis. The pivot shaft 20 is supported by a bracket 2d fixed to the aircraft body 2. A rear end 13b of the second link 13 is pivoted by a pivot shaft 21 so as to be rotatable about a horizontal axis. The pivot shaft 21 is disposed in front of and above the pivot shaft 17, and is supported by the lower part of the bracket 10k.

[0016] The upper end 14a of the lift cylinder 14 is pivoted freely around a horizontal axis by a pivot shaft 18. The pivot shaft 18 is provided in the center of the boom 10 and passes through the front of the bracket 10k. The lower end 14b of the lift cylinder 14 is pivoted freely around a horizontal axis by a pivot shaft 19. The pivot shaft 19 is provided in the rear lower part of the machine body 2.

[0017] As the lift cylinder 14 extends and retracts, the boom 10 swings up and down around the pivot shaft 16. That is, the front end 10a of the boom 10 moves up and down. The second link 13 swings up and down around the pivot shaft 20 in conjunction with the up and down swing of the boom 10. The first link 12 swings back and forth around the pivot shaft 17 in conjunction with the up and down swing of the second link 13. That is, the boom 10 can move in the fore and aft direction.

[0018] A hitch 24 is connected to the front end 10a of the boom 10 (working device 4). The hitch 24 is a connecting device for connecting the attachment 11, and is provided on the working machine 1. The front end 10a of the boom 10 is pivoted by a pivot shaft 23a provided at the bottom of the hitch 24 so as to be rotatable about a horizontal axis.

[0019] The tilt cylinders 15 are respectively disposed in front of the left and right booms 10. The upper end portions 15a of the tilt cylinders 15 are pivoted rotatably about the horizontal axis via pivot shafts 22. The pivot shafts 22 are provided on brackets 10j fixed to the curved portion 10c of the boom 10. The lower end portions 15b of the tilt cylinders 15 are pivoted rotatably about the horizontal axis by pivot shafts 23b provided on the top of the hitch 24.

[0020] As the tilt cylinder 15 extends and retracts, the hitch 24 swings around the pivot shaft 23a, causing the attachment 11 connected to the hitch 24 to swing up and down and back and forth. In other words, the attachment 11 is connected to the front end 10a of the boom 10 via the hitch 24 so as to be able to swing freely (tilt).

[0021] The attachment 11 is a work tool used to perform work. The attachment 11 is attached to the work device 4 and the work machine 1 by connecting to the front of the hitch 24. The attachment 11 can be removed from the work device 4 and the work machine 1 by disconnecting (disconnecting) the attachment 11 from the hitch 24. In other words, the attachment 11 can be attached to and detached from the hitch 24, the work device 4, and the work machine 1.

[0022] FIG. 11 shows a mulcher (felled tree crusher) as the attachment 11 attached to the work device 4 and the work machine 1 via a hitch 24. Attachments 11 other than mulchers can also be attached to the work device 4 and the work machine 1 via the hitch 24. Examples of attachable attachments 11 include crushers, breakers, grapples, angle brooms, earth augers, pallet forks, sweepers, mowers, and snow blowers. These attachments 11 are equipped with hydraulic actuators 27 that operate the attachments 11. The hydraulic actuators 27 include linear motion hydraulic actuators such as hydraulic cylinders and rotary motion hydraulic actuators such as hydraulic motors.

[0023] In addition to the attachment 11 described above, attachments such as buckets that are not equipped with hydraulic actuators 27 can also be used with the work machine 1. After an attachment that is not equipped with a hydraulic actuator 27 is attached to the front end 10a of the boom 10 via the hitch 24, the boom 10 is raised and lowered by the lift cylinder 14, and the attachment is swung by the tilt cylinder 15, thereby allowing a predetermined operation (such as excavation work) to be performed.

[0024] The hydraulic actuator 27 mounted on the attachment 11 is driven by hydraulic oil supplied from the work machine 1. An AUX coupler 25 is provided on the body 2 of the work machine 1. The AUX coupler 25 is an AUX port through which hydraulic oil flows in and out of the hydraulic actuator 27. The AUX coupler 25 includes a first AUX coupler 25a and a second AUX coupler 25b.

[0025] As shown in Fig. 11 , an operator connects external oil passage 26a, such as a hose, to first AUX coupler 25a and a first coupler provided on attachment 11, and connects external oil passage 26b to a second coupler provided on attachment 11 and second AUX coupler 25b. This allows hydraulic oil to be supplied from work equipment 1 to hydraulic actuator 27 of attachment 11, and allows hydraulic oil to return from hydraulic actuator 27 to work equipment 1. A hydraulic circuit is then established between work equipment 1 and hydraulic actuator 27, and hydraulic actuator 27 is driven by hydraulic oil from work equipment 1, which also drives attachment 11, enabling the attachment 11 to perform a predetermined task.

[0026] At least one of the hydraulic actuators 14, 15 provided on the working device 4 is driven by hydraulic oil to change the attitude (height, inclination, tilt angle, etc.) of the attachment 11. Furthermore, at least one of the hydraulic actuators 14, 15 and the hydraulic actuator 27 provided on the attachment 11 is driven to operate at least one of the working device 4 and the attachment 11 to perform work. Work by the working device 4 and the attachment 11 is performed when the working machine 1 is traveling on the traveling device 5 or when it is stopped traveling.

[0027] FIG. 1 is a diagram showing an example of a hydraulic circuit of a hydraulic system 100 mounted on a work machine 1. The hydraulic circuit of FIG. 1 is a hydraulic circuit for a work system. The hydraulic system 100 is equipped with a pilot pump P1 and a main pump P2. For example, the pilot pump P1 is a fixed displacement hydraulic pump, and the main pump P2 is a variable displacement hydraulic pump. The pilot pump P1 is operated by the power of the prime mover 6, and discharges hydraulic oil stored in a hydraulic oil tank T to a discharge oil passage 40. The hydraulic oil discharged by the pilot pump P1 is pilot oil for controlling various hydraulic devices provided in the work machine 1.

[0028] The main pump P2 is operated by the power of the prime mover 6 and discharges hydraulic oil stored in the hydraulic oil tank T to the main oil passage 45. The hydraulic oil discharged from the main pump P2 is used to operate the lift cylinder 14 and tilt cylinder 15 provided in the work device 4, and the hydraulic actuator 27 of the attachment 11.

[0029] The hydraulic system 100 includes a plurality of control valves 60. The plurality of control valves 60 include a lift control valve 60A, a tilt control valve 60B, and an AUX control valve 60C. The plurality of control valves 60 are capable of controlling the operation of the hydraulic actuators 14, 15, and 27, respectively. Each of the plurality of control valves 60 is connected to a main oil passage 45. The plurality of control valves 60 switches the flow rate (output) and supply direction of hydraulic oil supplied from the main oil passage 45 to the corresponding hydraulic actuators 14, 15, and 27, thereby controlling the operation of the corresponding hydraulic actuators 14, 15, and 27.

[0030] The lift control valve 60A is connected to the lift cylinder 14, which raises and lowers the boom 10, via multiple oil passages. The lift control valve 60A is a pilot-operated, direct-acting spool-type three-position switching valve. The lift control valve 60A has multiple work pressure receiving sections 61a, 61b, and switches between a third position (neutral position), a first position, and a second position depending on the pilot pressure acting on the work pressure receiving sections 61a, 61b. When the lift control valve 60A is in the third position, no hydraulic oil is supplied from the main oil passage 45 to the lift cylinder 14.

[0031] By switching the lift control valve 60A to either the first position or the second position, hydraulic oil is supplied from the main oil passage 45 to the lift cylinder 14, and the supply direction of the hydraulic oil is switched. Furthermore, when the lift control valve 60A is in either the first position or the second position, the opening of the lift control valve 60A changes according to the pilot pressure, which is the pressure of the pilot oil, thereby changing the flow rate of hydraulic oil supplied from the main oil passage 45 to the lift cylinder 14. In this way, the lift control valve 60A controls the flow rate and supply direction of hydraulic oil supplied to the lift cylinder 14, causing the lift cylinder 14 to extend or retract.

[0032] The tilt control valve 60B is connected to the tilt cylinder 15, which swings the attachment 11, by multiple oil passages. The tilt control valve 60B is a pilot-operated direct-acting spool-type three-position switching valve. The tilt control valve 60B has multiple work pressure receiving portions 62a, 62b, and switches between a third position (neutral position), a first position, and a second position depending on the pilot pressure acting on the work pressure receiving portions 62a, 62b. When the tilt control valve 60B is in the third position, hydraulic oil is not supplied from the main oil passage 45 to the tilt cylinder 15.

[0033] By switching the tilt control valve 60B to either the first position or the second position, hydraulic oil is supplied from the main oil passage 45 to the tilt cylinder 15, and the supply direction of the hydraulic oil is switched. Furthermore, when the tilt control valve 60B is in either the first position or the second position, the opening degree of the tilt control valve 60B changes in accordance with the pilot pressure, thereby changing the flow rate of hydraulic oil supplied from the main oil passage 45 to the tilt cylinder 15. In this way, the tilt control valve 60B controls the flow rate and supply direction of hydraulic oil supplied from the main oil passage 45 to the tilt cylinder 15, causing the tilt cylinder 15 to extend and retract.

[0034] The AUX control valve 60C is connected to the AUX coupler 25 via multiple oil passages 64. Specifically, a first port of the AUX control valve 60C is connected to the first AUX coupler 25a via an oil passage 64a, and a second port of the AUX control valve 60C is connected to the second AUX coupler 25b via an oil passage 64b. The AUX control valve 60C is a pilot-operated direct-acting spool-type three-position switching valve. The AUX control valve 60C has multiple AUX pressure receiving portions 63a, 63b, and is switched between a third position (neutral position) 60d, a first position 60a different from the third position 60d, and a second position 60b different from the third position 60d and the first position 60a, depending on the pilot pressure acting on the AUX pressure receiving portions 63a, 63b.

[0035] When the AUX control valve 60C is in the third position 60d, hydraulic oil is not supplied from the main oil passage 45 to the hydraulic actuator 27 of the attachment 11 via the oil passage 64 and the AUX coupler 25. When the AUX control valve 60C is switched to either the first position 60a or the second position 60b, hydraulic oil is supplied from the main oil passage 45 to the hydraulic actuator 27 via the oil passage 64 and the AUX coupler 25, and the supply direction of the hydraulic oil is switched.

[0036] Specifically, when the AUX control valve 60C is switched to the first position 60a, the hydraulic oil flowing from the main oil passage 45 to the AUX control valve 60C is supplied to the hydraulic actuator 27 via the oil passage 64a and the first AUX coupler 25a, etc., and the hydraulic oil discharged from the hydraulic actuator 27 returns to the AUX control valve 60C via the second AUX coupler 25b and the oil passage 64b, and is discharged from the AUX control valve 60C. Also, when the AUX control valve 60C is switched to the second position 60b, the hydraulic oil flowing from the main oil passage 45 to the AUX control valve 60C is supplied to the hydraulic actuator 27 via the oil passage 64b and the second AUX coupler 25b, and the hydraulic oil discharged from the hydraulic actuator 27 returns to the AUX control valve 60C via the first AUX coupler 25a and the oil passage 64a, and is discharged from the AUX control valve 60C.

[0037] Furthermore, when the AUX control valve 60C is in either the first position 60a or the second position 60b, the opening degree of the AUX control valve 60C changes in response to the pilot pressure, thereby changing the flow rate and pressure of the hydraulic oil supplied from the main oil passage 45 to the hydraulic actuator 27 via the AUX coupler 25. In this way, the AUX control valve 60C controls the supply direction, flow rate, and pressure of the hydraulic oil supplied from the main oil passage 45 to the hydraulic actuator 27 via the oil passage 64 and the AUX coupler 25 in response to the pilot pressure acting on the AUX pressure receiving portions 63a, 63b, thereby operating the hydraulic actuator 27.

[0038] The hydraulic system 100 includes a plurality of AUX electromagnetic control valves 65 that change the position and aperture of an AUX control valve 60C to adjust the flow rate and pressure of hydraulic oil supplied to the hydraulic actuator 27. Each of the plurality of AUX electromagnetic control valves 65 is an electromagnetic proportional valve whose solenoid is excited and whose aperture changes in response to an input current value (control signal). Each of the plurality of AUX electromagnetic control valves 65 is provided in a branch oil passage 40c branched from the discharge oil passage 40, and changes its aperture to change the pilot pressure of the pilot oil supplied from the discharge oil passage 40. As the current value input to each of the plurality of AUX electromagnetic control valves 65 increases, the aperture of each of the plurality of AUX electromagnetic control valves 65 increases, and the pilot pressure output from each of the plurality of AUX electromagnetic control valves 65 increases.

[0039] The multiple AUX electromagnetic control valves 65 include a first AUX electromagnetic control valve 65A and a second AUX electromagnetic control valve 65B. The first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B are connected to the AUX pressure receiving portions 63a, 63b of the AUX control valve 60C, respectively, by a control oil passage 66. More specifically, the control oil passage 66 includes a first control oil passage 66a connecting the first AUX electromagnetic control valve 65A and the AUX pressure receiving portion 63a of the AUX control valve 60C, and a second control oil passage 66b connecting the second AUX electromagnetic control valve 65B and the AUX pressure receiving portion 63b of the AUX control valve 60C.

[0040] When the opening degree of the first AUX electromagnetic control valve 65A becomes greater than 0 (zero), pilot oil from the discharge oil passage 40 acts on the AUX pressure receiving portion 63a of the AUX control valve 60C via the first AUX electromagnetic control valve 65A and the first control oil passage 66a. At this time, pilot pressure according to the opening degree of the first AUX electromagnetic control valve 65A acts on the AUX pressure receiving portion 63a. When the pilot pressure acting on the AUX pressure receiving portion 63a reaches or exceeds a predetermined value, a spool provided in the AUX control valve 60C moves, and the AUX control valve 60C switches from the third position 60d to the first position 60a. This allows hydraulic oil to be supplied from the AUX control valve 60C to the hydraulic actuator 27 via the oil passage 64a and the first AUX coupler 25a.

[0041] Furthermore, the opening degree of the first AUX electromagnetic control valve 65A changes, and the pilot pressure acting on the AUX pressure receiving portion 63a changes, which in turn changes the opening degree of the first position 60a of the AUX control valve 60C. The change in the opening degree of the first position 60a changes the flow rate and pressure of the hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 via the oil passage 64a and the first AUX coupler 25a.

[0042] When the opening degree of the second AUX electromagnetic control valve 65B becomes greater than 0 (zero), pilot oil from the discharge oil passage 40 acts on the AUX pressure receiving portion 63b of the AUX control valve 60C via the second AUX electromagnetic control valve 65B and the second control oil passage 66b. At this time, pilot pressure according to the opening degree of the second AUX electromagnetic control valve 65B acts on the AUX pressure receiving portion 63b. When the pilot pressure acting on the AUX pressure receiving portion 63b reaches or exceeds a predetermined value, the spool of the AUX control valve 60C moves, and the AUX control valve 60C switches from the third position 60d to the second position 60b. This allows hydraulic oil to be supplied from the AUX control valve 60C to the hydraulic actuator 27 via the oil passage 64b and the second AUX coupler 25b.

[0043] Furthermore, the aperture of the second AUX electromagnetic control valve 65B changes, and the pilot pressure acting on the AUX pressure receiving portion 63b changes, which in turn changes the aperture of the second position 60b of the AUX control valve 60C. The change in the aperture of the second position 60b changes the flow rate and pressure of the hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 via the oil passage 64b and the second AUX coupler 25b.

[0044] As described above, the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B change the pilot pressure acting on the AUX pressure receiving sections 63a, 63b of the AUX control valve 60C according to the input current value, thereby changing the flow rate and pressure of hydraulic oil from the AUX control valve 60C to the hydraulic actuator 27.

[0045] The work implement 1 is equipped with a work operation device 67. The work operation device 67 is a device that operates the lift cylinder 14 and tilt cylinder 15 of the work implement 4. The work operation device 67 switches the flow rate and supply direction of hydraulic oil supplied to the lift cylinder 14 and tilt cylinder 15 by changing the pilot pressures acting on the work pressure receiving portions 61a, 61b, 62a, and 62b of the lift control valve 60A and the tilt control valve 60B, respectively. The work operation device 67 includes a work operation member 68 and a plurality of work operation valves 69.

[0046] The work operation member 68 can be operated to swing in at least four directions with a neutral position as a reference. The multiple work operation valves 69 operate in response to the operation of the work operation member 68. The multiple work operation valves 69 are connected to the discharge oil passage 40, and change the pilot pressure of the pilot oil supplied from the discharge oil passage 40. The multiple work operation valves 69 are a first pilot valve 69A, a second pilot valve 69B, a third pilot valve 69C, and a fourth pilot valve 69D.

[0047] The plurality of work operation valves 69 are connected to the plurality of control valves 60 by work oil passages 46 (46a to 46d). Of these, the first work oil passage 46a is an oil passage that connects the first pilot valve 69A and the work pressure receiving portion 61a of the lift control valve 60A. The second work oil passage 46b is an oil passage that connects the second pilot valve 69B and the work pressure receiving portion 61b of the lift control valve 60A. The third work oil passage 46c is an oil passage that connects the third pilot valve 69C and the work pressure receiving portion 62a of the tilt control valve 60B. The fourth work oil passage 46d is an oil passage that connects the fourth pilot valve 69D and the work pressure receiving portion 62b of the tilt control valve 60B.

[0048] When the work operating member 68 is swung forward (in the A1 direction), pilot oil is supplied from the first pilot valve 69A to the first work oil passage 46a, and the pilot pressure of the pilot oil acts on the work pressure receiving portion 61a of the lift control valve 60A via the first work oil passage 46a. As a result, the lift control valve 60A changes the flow rate and supply direction of the hydraulic oil supplied to the lift cylinder 14, causing the lift cylinder 14 to contract and lower the boom 10.

[0049] When the work operating member 68 is swung rearward (in the direction A2), pilot oil is supplied from the second pilot valve 69B to the second work oil passage 46b, and the pilot pressure of the pilot oil acts on the work pressure receiving portion 61b of the lift control valve 60A via the second work oil passage 46b. As a result, the lift control valve 60A changes the flow rate and supply direction of the hydraulic oil supplied to the lift cylinder 14, so the lift cylinder 14 extends and the boom 10 rises.

[0050] When the work operating member 68 is swung to the left (direction A3), pilot oil is supplied from the third pilot valve 69C to the third work oil line 46c, and the pilot pressure of the pilot oil acts on the work pressure receiving portion 62a of the tilt control valve 60B via the third work oil line 46c. As a result, the tilt control valve 60B changes the flow rate and supply direction of the hydraulic oil supplied to the tilt cylinder 15, causing the tilt cylinder 15 to contract and the attachment 11 to swing upward.

[0051] When the work operating member 68 is swung to the right (direction A4), pilot oil is supplied from the fourth pilot valve 69D to the fourth work oil line 46d, and the pilot pressure of the pilot oil acts on the work pressure receiving portion 62b of the tilt control valve 60B via the fourth work oil line 46d. As a result, the tilt control valve 60B changes the flow rate and supply direction of the hydraulic oil supplied to the tilt cylinder 15, so the tilt cylinder 15 extends and the attachment 11 swings downward.

[0052] The hydraulic system 100 includes an LS system (load sensing system) 80. The LS system 80 controls the flow rate of hydraulic oil discharged by the main pump P2 so that the differential pressure obtained by subtracting the maximum load pressure among the load pressures of the multiple hydraulic actuators 14, 15, 27 operated by the hydraulic oil discharged by the main pump P2 from the discharge pressure of the hydraulic oil by the variable displacement main pump P2 becomes a constant pressure.

[0053] The LS system 80 includes a swash plate changing cylinder 81, a flow rate compensation valve 82, and an opening degree changing cylinder 83. The swash plate changing cylinder 81 adjusts the angle of the swash plate of the main pump P2. The flow rate compensation valve 82 applies hydraulic pressure to the swash plate changing cylinder 81 to operate it. The opening degree changing cylinder 83 is actuated by the pilot pressure of the pilot oil from the pilot pump P1 to change the opening degree of the flow rate compensation valve 82.

[0054] A PLS oil line 84 and a PPS oil line 85 are connected to the flow rate compensation valve 82. The PLS oil line 84 is an oil line that transmits the PLS pressure, which is the highest load pressure (maximum actuator load pressure) among the load pressures of the multiple hydraulic actuators 14, 15, and 27. The PPS oil line 85 is an oil line that transmits the PPS pressure, which is the discharge pressure of the main pump P2. The flow rate compensation valve 82 activates the swash plate changing cylinder 81 to adjust the angle of the swash plate of the main pump P2 so that the differential pressure obtained by subtracting the PLS pressure from the PPS pressure becomes a constant pressure. This controls the amount of hydraulic oil discharged by the main pump P2, and hydraulic pressure (power) corresponding to the load on the work device 4 and the attachment 11 is output from the main pump P2.

[0055] The main pump P2 is configured so that its own pressure presses the swash plate of the main pump P2 in a direction that increases the amount of hydraulic oil discharged from the main pump P2. The swash plate changing cylinder 81 is configured to apply a force to the swash plate that counteracts the own pressure of the main pump P2. The flow rate compensation valve 82 is configured to adjust the hydraulic pressure acting on the swash plate changing cylinder 81 to control the amount of hydraulic oil discharged from the main pump P2. Therefore, when the hydraulic pressure acting on the swash plate changing cylinder 81 is released (returns to zero), the angle of the swash plate of the main pump P2 becomes the maximum angle, and the flow rate of hydraulic oil discharged from the main pump P2 becomes the maximum flow rate.

[0056] In addition to the hydraulic circuit for work shown in FIG. 1 , the hydraulic system 100 also includes a hydraulic circuit for traveling to travel the work machine 1. The hydraulic circuit for traveling includes multiple travel pumps, multiple travel motors, and a travel operation device. The multiple travel pumps and multiple travel motors are provided to correspond to the first travel device 5 and the second travel device 5. The multiple travel pumps are driven by the power of the prime mover 6. The multiple travel motors are rotationally driven by hydraulic oil discharged from the corresponding travel pumps. The rotational driving of the multiple travel motors drives the first travel device 5 and the second travel device 5, causing the work machine 1 to travel. The multiple travel pumps, multiple travel motors, and multiple travel devices 5 are operated by the travel operation device. Specifically, when the driver operates a travel operation member included in the travel operation device, the discharge direction of hydraulic oil from the multiple travel pumps is changed, the rotation direction of the multiple travel motors is changed, and the rotation direction of the multiple travel devices 5 is also changed, causing the work machine 1 to move forward, backward, turn right, and turn left.

[0057] 2 is a diagram showing an example of the electrical configuration of the hydraulic system 100 of the work machine 1. The work machine 1 and the hydraulic system 100 are equipped with a control device 30, a memory 31, a user interface 32, an accelerator device 33, an AUX operation device 34, a rotation speed sensor 36, a temperature sensor 37, AUX pressure sensors 38a and 38b, and an AUX connector 39.

[0058] The control device 30 includes a processor such as a CPU, a memory 31, and the like. The control device 30 is a controller for the work machine 1 and the hydraulic system 100. The memory 31 is a volatile or non-volatile memory. The memory 31 is a storage device for the work machine 1 and the hydraulic system 100. The memory 31 stores software programs and data used by the control device 30 to control each part of the work machine 1 and the hydraulic system 100. The memory 31 also stores data used by the control device 30 to control each part of the work machine 1 and the hydraulic system 100. As another example, a memory (storage device) separate from the control device 30 may be provided in the work machine 1 and the hydraulic system 100.

[0059] The user interface 32 is, for example, a touch panel or tablet-type terminal device, and has a display that displays information. The control device 30 displays (outputs) various information related to the work machine 1 stored in its internal memory or memory 31 to a user, such as the driver of the work machine 1, via the user interface 32. The user can also input various information and instructions to the control device 30 (work machine 1) by operating the user interface 32. The control device 30 stores the information input via the user interface 32 in the memory 31.

[0060] A user can input attachment information, which is information relating to an attachment 11 attached to the work machine 1, through the user interface 32. For example, the control device 30 reads data for a plurality of icons representing each of a plurality of attachments 11 that can be attached to the work machine 1 from the memory 31, and causes the user interface 32 to display the plurality of icons on a predetermined input screen. Then, when the user performs an operation on the user interface 32 to select an icon representing the attachment 11 attached to the work machine 1 from the plurality of displayed icons, the control device 30 accepts the selected icon as attachment information, reads other identification information (such as name, model number, and ID) of the attachment 11 corresponding to the attachment information from the memory 31, and also treats the read identification information as attachment information.

[0061] As another example, the system may be configured so that a user manually inputs identification information, such as the name and model number, of the attachment 11 attached to the work machine 1 as attachment information via the user interface 32. Furthermore, the control device 30 may read other information about the attachment 11 corresponding to the identification information from the memory 31 based on the identification information of the attachment 11 input via the user interface 32, and treat the read information and the input identification information as the attachment information. The user interface 32 is an output device (output interface) and also an input device (input interface) for the work machine 1 and the hydraulic system 100. Furthermore, the user interface 32 is an example of an input device (second input device) for inputting attachment information.

[0062] The accelerator device 33 and AUX operating device 34 are installed near the driver's seat 8 inside the cabin 3 and are operated by the driver of the work machine 1. The accelerator device 33 is a device for inputting the target rotation speed of the prime mover (engine) 6, and includes an accelerator operating member and an accelerator sensor. The accelerator operating member is an operating member such as a lever, pedal, dial, or slider. The accelerator sensor outputs a signal corresponding to the operating position of the accelerator operating member. The control device 30 determines the target rotation speed of the prime mover 6 based on the accelerator signal output from the accelerator sensor of the accelerator device 33. That is, the accelerator device 33 inputs a signal corresponding to the target rotation speed of the prime mover 6 to the control device 30.

[0063] The AUX operation device 34 includes an AUX mode switch 34a, an AUX operation switch 34b, and an AUX volume switch 34c. The AUX operation device 34 is an example of an input device (input interface, first input device) that inputs an operation instruction for the attachment 11.

[0064] The AUX mode switch 34a is an operation switch that is operated to turn on an AUX mode in which hydraulic oil is supplied from the work machine 1 to the hydraulic actuator 27 mounted on the attachment 11. When the driver turns on the AUX mode switch 34a, an operation signal (electrical signal) corresponding to the on operation is input from the AUX operation device 34 to the control device 30, and the control device 30 (work machine 1) that receives the operation signal transitions to the AUX mode.

[0065] The AUX operation switch 34b is an operation switch that is operated to input an operation command for the attachment 11 equipped with the hydraulic actuator 27. When the driver performs a predetermined start operation on the AUX operation switch 34b, an operation signal (electrical signal) indicating a start command for the attachment 11 is input from the AUX operation device 34 to the control device 30. When the driver performs a predetermined stop operation on the AUX operation switch 34b, an operation signal (electrical signal) indicating a stop command for the attachment 11 is input from the AUX operation device 34 to the control device 30.

[0066] When a command to start the attachment 11 is input from the AUX operating device 34, the control device 30 changes the input current value input to the AUX electromagnetic control valves 65A, 65B to control the aperture of the AUX electromagnetic control valves 65A, 65B and open one of the AUX electromagnetic control valves 65A, 65B. This changes the pilot pressure acting on the AUX control valve 60C from the AUX electromagnetic control valves 65A, 65B, causing the AUX control valve 60C to switch to the first position 60a or the second position 60b, and hydraulic oil is supplied to the hydraulic actuator 27 of the attachment 11 via the AUX control valve 60C and the AUX coupler 25, starting the hydraulic actuator 27 and the attachment 11.

[0067] Furthermore, when a command to stop the attachment 11 is input from the AUX operating device 34, the control device 30 changes the input current value input to the AUX electromagnetic control valves 65A, 65B to control the opening of the AUX electromagnetic control valves 65A, 65B and closes the AUX electromagnetic control valves 65A, 65B. This changes the pilot pressure acting on the AUX control valve 60C from the AUX electromagnetic control valves 65A, 65B, causing the AUX control valve 60C to switch to the third position (neutral position) 60d, preventing the supply of hydraulic oil to the hydraulic actuator 27 and causing the hydraulic actuator 27 and the attachment 11 to stop.

[0068] The AUX volume switch 34c is an operating switch (operating member) that is operated to set and adjust the flow rate and pressure of hydraulic oil supplied to the hydraulic actuator 27 mounted on the attachment 11. The AUX volume switch 34c includes an operating tool such as a slider, dial, or push button that is operated by the driver or the like by hand, and a displacement sensor that detects the amount of displacement of the operating tool.

[0069] When the AUX volume switch 34c is operated, a detection signal corresponding to the operation (amount of displacement) is output from the displacement sensor, and the AUX operation device 34 outputs an operation signal (electrical signal) corresponding to the detection signal of the displacement sensor to the control device 30. The control device 30 detects the operation amount (amount of displacement) of the AUX volume switch 34c based on the operation signal output from the AUX operation device 34, determines the input current value to be input to the AUX electromagnetic control valves 65A, 65B based on the operation amount, and inputs the input current value to one of the AUX electromagnetic control valves 65A, 65B. As a result, the apertures of the AUX electromagnetic control valves 65A, 65B are set and adjusted, the pilot pressure acting on the AUX control valve 60C from the AUX electromagnetic control valves 65A, 65B changes, the aperture of the AUX control valve 60C is also set and adjusted, and the flow rate and pressure of the hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 are also set and adjusted.

[0070] The rotation speed sensor 36 detects the actual rotation speed of the prime mover 6. The control device 30 controls the driving of the prime mover 6 so that the actual rotation speed of the prime mover 6 matches the target rotation speed input by the accelerator device 33. The temperature sensor 37 detects the temperature of the hydraulic oil. The rotation speed sensor 36 is an example of a rotation speed detection device, and the temperature sensor 37 is an example of a temperature detection device.

[0071] The AUX pressure sensors 38a and 38b are connected to the oil passages 64a and 64b shown in FIG. 1, respectively, and detect the pressure of hydraulic oil acting on the AUX couplers 25a and 25b from the AUX control valve 60C, i.e., the pressure of hydraulic oil supplied to the hydraulic actuator 27 of the attachment 11. The control device 30 detects the supply status, such as the presence, flow rate, and pressure, of hydraulic oil being supplied to the hydraulic actuator 27 based on the hydraulic oil pressure detected by the AUX pressure sensors 38a and 38b. The control device 30 then adjusts the apertures of the AUX control valve 60C and the AUX electromagnetic control valves 65A and 65B based on the detected supply status of hydraulic oil, and determines whether the hydraulic actuator 27 and the attachment 11 are operating or stopped. The AUX pressure sensors 38a and 38b are an example of a pressure detection device.

[0072] The attachment 11 includes an attachment 11 equipped with an electronic device and an attachment 11 not equipped with an electronic device. The attachment 11 equipped with an electronic device is provided with a connector 49. When an electrical harness is connected between the connector 49 and the AUX connector 39 of the work implement 1, the electronic device of the attachment 11 and the control device 30 are electrically connected, enabling input and output of electrical signals and information between the electronic device and the control device 30. The AUX connector 39 is a connection device for electrically connecting the attachment 11 to the work implement 1.

[0073] The electronic device mounted on the attachment 11 includes a processing unit 47 and a pressure sensor 48. The processing unit 47 has a CPU, memory, etc. The processing unit 47 transmits attachment information related to the attachment 11 mounted thereon to the control device 30 via a connector 49, an electric harness, and an AUX connector 39. The attachment information transmitted by the processing unit 47 includes at least one of identification information such as the ID, model number, and name of the attachment 11. The AUX connector 39 is an example of an input device (input interface, second input device) that inputs attachment information from the processing unit 47.

[0074] The pressure sensor 48 detects the pressure of hydraulic oil supplied from the work machine 1 to the hydraulic actuator 27. In addition, the attachment 11 may be provided with a pressure sensor that detects the pressure of hydraulic oil returning from the hydraulic actuator 27 to the work machine 1. Detection signals from the pressure sensor 48 and the like are input to the control device 30 via the connector 49, the electrical harness, and the AUX connector 39. The control device 30 may detect the supply status, such as the presence or absence, flow rate, and pressure, of hydraulic oil being supplied to the hydraulic actuator 27 based on the pressure of the hydraulic oil detected by the pressure sensor 48 and the like. Furthermore, the control device 30 may adjust the apertures of the AUX control valve 60C and the AUX electromagnetic control valves 65A, 65B based on the detected supply status of hydraulic oil, and determine whether the hydraulic actuator 27 and the attachment 11 are in an operating state or a stopped state. The pressure sensor 48 is an example of a pressure detection device.

[0075] As described above, when attachment information is input from the arithmetic processing device 47 or the user interface 32, the control device 30 identifies (recognizes) the attachment 11 attached to the work machine 1 based on the input attachment information. At this time, the control device 30 may read other information related to the attachment 11 corresponding to the input attachment information from the memory 31 and identify the attachment 11 based on the read information. The control device 30 then controls the flow rate and pressure of hydraulic oil supplied from the AUX coupler 25 to the hydraulic actuator 27 of the attachment 11 according to the identified attachment 11. To perform this control, the memory 31 stores control data corresponding to the attachments 11 that can be used with the work machine 1.

[0076] Fig. 3 is a diagram showing an example of control data for an attachment 11. Specifically, Fig. 3 shows, in a table format, the names of attachments 11 that can be used with the work machine 1, identification information other than the names of the attachments 11, and control data for the attachments 11. This information and control data are associated with each attachment 11 and stored in the memory 31. Furthermore, the control data is set based on data obtained by attaching a usable attachment 11 to the work machine 1 and conducting a test before the user uses the work machine 1.

[0077] The identification information in Fig. 3 includes at least one of the ID, model number, and serial number of the attachment 11. The control data is data for controlling the AUX electromagnetic control valves 65A, 65B, which adjust the flow rate and pressure of hydraulic oil supplied to the hydraulic actuator 27 of the attachment 11. The control data includes a target opening, a target current value (second current value), and a switching current value (first current value) of the AUX electromagnetic control valves 65A, 65B when starting the hydraulic actuator 27 and the attachment 11. The control data also includes a target opening, a target current value (fourth current value), and a switching current value (third current value) of the AUX electromagnetic control valves 65A, 65B when stopping the hydraulic actuator 27 and the attachment 11.

[0078] The target opening refers to the target opening of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B. When starting the attachment 11, the supply direction of hydraulic oil supplied from the AUX control valve 60C in FIG. 1 to the hydraulic actuator 27 via the oil passage 64 and the AUX coupler 25 is set for each attachment 11. For this reason, when starting the attachment 11, the target opening of the inactive AUX electromagnetic control valve, which is the AUX electromagnetic control valve that is not activated, of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B is 0 (zero), and the target opening of the active AUX electromagnetic control valve, which is the AUX control valve that is activated, is a value greater than 0. When stopping the attachment 11, the target openings of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B are both 0.

[0079] The target current value is a target current value input to the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B to set the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B to their target openings. The target current value and the target opening correspond to each other. When starting the attachment 11, the target current value of the inactive AUX electromagnetic control valve of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B, whose target opening is 0 (zero)%, is 0 [A] (zero amperes), and the target current value (second current value) of the active AUX electromagnetic control valve, whose target opening is greater than 0%, is greater than 0 [A]. The target current value of the active AUX electromagnetic control valve may be the maximum value within the settable current range. When stopping the attachment 11, the target current values ​​(fourth current value) of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B are both 0 [A].

[0080] The switching current value is a switching point (inflection point) that switches (changes) the amount of current change per unit time when changing the input current value input to the operating AUX electromagnetic control valve to the target current value, among the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B. More specifically, the switching current value is the current value that switches the input current value to the operating AUX electromagnetic control valve from a step input to a ramp input or from a ramp input to a step input.

[0081] FIG. 4 is a diagram showing an example of changes in the input current values to the AUX electromagnetic control valves 65A and 65B when starting or stopping the attachment 11 equipped with the hydraulic actuator 27. In order to start the attachment 11 attached to the work machine 1 from a stopped state, the input current value to the operating AUX electromagnetic control valve among the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B is increased from 0 A. As a result, for example, as shown by the solid line in the left part of FIG. 4, until the input current value reaches the target current value (second current value) Q2, the operating AUX electromagnetic control valve and the AUX control valve 60C open, and the hydraulic oil is supplied to the hydraulic actuator 27, so the hydraulic actuator 27 and the attachment 11 start to move (start).

[0082] In order to start the attachment 11 etc. (and the hydraulic actuator 27) in a stable predetermined state, the target current value Q2 is set to a value higher than the starting point Q1a which is the input current value at which the attachment 11 starts to move (start).

[0083] The switching current value (first current value) Q1 when starting the attachment 11 is set to a relatively high current value within the current range (second current range at startup) R2a (0 [A] or more and less than the starting point Q1a, 0≦R2a<Q1a) where the attachment 11 does not operate. More specifically, the switching current value Q1 is set to a value lower than the starting point Q1a by a first predetermined value. That is, the switching current value Q1 is set to the current value corresponding to immediately before the attachment 11 starts to move (immediately before starting). The difference (first predetermined value) between the switching current value Q1 and the starting point Q1a is set to be smaller than the difference between the starting point Q1a and the target current value Q2.

[0084] The input current value to the operating AUX solenoid control valve is input in steps from 0 [A] to the switching current value Q1, and then input in a ramp from the switching current value Q1 to the target current value Q2. As a result, the input current value to the operating AUX solenoid control valve rises in one go up to the switching current value Q1, and then gradually rises from the switching current value Q1 to the target current value Q2.

[0085] That is, in the majority of the current range R2a in which the attachment 11 does not operate, that is, above 0 [A] and below the switching current value Q1, the input current value to the operating AUX electromagnetic control valve rises sharply, whereas in the current range (first current range at startup) R1a in which the attachment 11 operates (above the starting point Q1a and below the target current value Q2, Q1≦R1a≦Q2), the input current value to the operating AUX electromagnetic control valve rises gradually. Also, the amount of current change per unit time until the input current value to the operating AUX electromagnetic control valve reaches the switching current value Q1 is smaller than the amount of current change per unit time until the input current value reaches the switching current value Q1.

[0086] When the input current value to the operating AUX solenoid control valve is reduced to a target current value (fourth current value; 0 [A]) Q4 in order to stop the attachment 11 attached to the work machine 1 from a driving state, the opening of the operating AUX solenoid control valve and the AUX control valve 60C becomes smaller by the time the input current value reaches the target current value Q4, as shown by the solid line on the right side of Figure 4, and the amount of hydraulic oil supplied to the hydraulic actuator 27 decreases, causing the attachment 11 to stop moving (stop). In this way, the stop point Q3a, which is the input current value at which the attachment 11 stops moving (stops), is a value higher than the target current value Q4 for stopping the attachment 11 in a stable, predetermined state (completely stopping).

[0087] The switching current value (third current value) Q3 when stopping the attachment 11 is set to a relatively high current value within the current range (second current range at stop) R2b where the attachment 11 does not operate (below the stop point Q3a and above the target current value Q4, Q4≦R2b≦Q3a). More specifically, the switching current value Q3 is set to a value that is lower than the stop point Q3a by a second predetermined value. That is, the switching current value Q3 is set to the current value corresponding immediately after the attachment 11 stops operating (immediately after stopping). The difference (second predetermined value) between the switching current value Q3 and the stop point Q3a is set to be smaller than the difference between the stop point Q3a and the target current value Q4.

[0088] Also, since the stop point Q3a is lower than the start point Q1a, the switching current value Q3 at stop is set to a value lower than the switching current value Q1 at start. Also, the switching current values Q1 and Q3 are set to values lower than the target current value Q2 at start and higher than the target current value Q4 at stop.

[0089] The input current value to the operating AUX electromagnetic control valve is ramp - input from the drive current value Q2x when the attachment 11 is being driven to the switching current value Q3, and step - input from the switching current value Q3 to the target current value Q4. Thereby, the input current value to the operating AUX electromagnetic control valve gradually decreases until the switching current value Q3, and suddenly decreases from the switching current value Q3 to the target current value Q4.

[0090] That is, within the current range (first current range at stop) R1b where the attachment 11 operates (below the drive current value Q2x and larger than the stop point Q3a, Q3a<R1b≦Q2x), the input current value to the operating AUX electromagnetic control valve gradually decreases, and within the current range R2b where the attachment 11 does not operate, the input current value to the operating AUX electromagnetic control valve suddenly decreases. Also, the amount of current change per unit time until the input current value to the operating AUX electromagnetic control valve reaches the switching current value Q3 is less than the amount of current change per unit time from when the input current value reaches the switching current value Q3 to when it reaches the target current value Q4.

[0091] When starting or stopping the attachment 11 attached to the work machine 1, the control device 30 changes the input current value to the operating AUX electromagnetic control valves 65A, 65B to the target current values ​​Q2, Q4 based on the control data corresponding to the attachment 11, and sets the openings of the operating AUX electromagnetic control valves 65A, 65B to the target openings. This switches the position of the AUX control valve 60C in Fig. 1, causing the hydraulic oil to flow into or stop flowing to the hydraulic actuator 27, and starting or stopping the hydraulic actuator 27 and the attachment 11.

[0092] Furthermore, when starting or stopping the attachment 11, the control device 30 changes the input current value to the operating AUX solenoid control valves 65A, 65B up to the target current values ​​Q2, Q4, and changes the input method of the input current value to either step input or ramp input before and after the input current value reaches the switching current values ​​Q1, Q3, and also changes the amount of current change per unit time. Furthermore, the control device 30 gradually changes the input current value to the operating AUX solenoid control valves 65A, 65B within the current ranges R1a, R1b in which the attachment 11 operates.

[0093] In the example shown in FIG. 4, the drive current value Q2x is the same as the target current value Q2 at the time of activation, but the drive current value Q2x may be a value different from the target current value Q2. The drive current value Q2x can be changed by operating the AUX volume switch 34c. For example, when the driver (user) operates the AUX volume switch 34c to drive the activated attachment 11, the control device 30 detects the amount of operation of the AUX volume switch 34c based on an operation signal output from the AUX operation device 34 in response to the operation of the AUX volume switch 34c, and determines the drive current value Q2x based on the amount of operation. As a result, the drive current value Q2x is set to a value different from the target current value Q2 corresponding to the attachment 11.

[0094] The control device 30 then inputs the drive current value Q2x determined in response to the operation of the AUX volume switch 34c as described above to the operating AUX electromagnetic control valves 65A, 65B. This changes the input current value to the operating AUX electromagnetic control valves 65A, 65B, changes the apertures of the operating AUX electromagnetic control valves 65A, 65B and the AUX control valve 60C, and also changes the flow rate and pressure of the hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27, changing the drive states of the hydraulic actuator 27 and the attachment 11.

[0095] Thereafter, when stopping the attachment 11, the control device 30 gradually reduces the input current value to the operating AUX electromagnetic control valves 65A, 65B from a drive current value Q2x, which is different from the target current value Q2, to a third current value Q3 (ramp input), and further reduces the input current value to the operating AUX electromagnetic control valves 65A, 65B from the third current value Q3 to a fourth current value Q4 in one go (step input).

[0096] Figure 5 is a flowchart showing an example of the attachment use process. When the attachment 11 equipped with the hydraulic actuator 27 is used with the work machine 1, the control device 30 executes the attachment use process in accordance with a software program stored in the memory 31. For convenience, the attachment 11 is represented as "ATT" in Figure 5.

[0097] When an operator uses an attachment 11 equipped with a hydraulic actuator 27 with a work machine 1, the operator mounts the attachment 11 to the work machine 1 via the hitch 24 (FIG. 1) and connects external oil passages 26a, 26b to the coupler of the attachment 11 and the AUX coupler 25. If the attachment 11 is equipped with an electronic device, the operator connects an electrical harness to the connector 49 of the attachment 11 and the AUX connector 39 (FIG. 2). When the operator of the work machine 1 turns on the AUX mode switch 34a, the control device 30 detects this on operation, transitions to the AUX mode, and acquires attachment information from at least one of the arithmetic processing device 47 and the user interface 32 of the attachment 11 (S1 in FIG. 5).

[0098] If an arithmetic processing device 47 is installed on the attachment 11 attached to the work machine 1, attachment information regarding the attachment 11 is input from the arithmetic processing device 47 via an AUX connector 39 or the like, and the control device 30 acquires the attachment information (S1).

[0099] On the other hand, if the attachment 11 attached to the work implement 1 is not equipped with a processing unit 47, attachment information will not be input from the AUX connector 39. To address this, for example, if a predetermined time has passed since the AUX mode switch 34a was turned on without any attachment information being input from the AUX connector 39, the control device 30 causes the user interface 32 to display an input screen for inputting attachment information. Then, when the driver operates the user interface 32 to input attachment information (icon, name, or model number) of the attachment 11 attached to the work implement 1 into the input screen, the control device 30 acquires the input attachment information (S1).

[0100] As another example, the control device 30 may display an input screen using the user interface 32, regardless of whether or not the attachment information is input from the arithmetic processing device 47. When attachment information is input from both the arithmetic processing device 47 and the user interface 32, and the two pieces of input attachment information indicate the same attachment 11, the control device 30 may acquire (adopt) at least one of the two pieces of input attachment information as the attachment information of the attachment 11 attached to the work implement 1.

[0101] Furthermore, if the attachment information received from the arithmetic processing device 47 and the user interface 32 do not indicate the same attachment 11, the control device 30 may not acquire the two pieces of input attachment information as the attachment information of the attachment 11 attached to the work implement 1, but may output a message confirming the attached attachment 11 via the user interface 32. The control device 30 may then wait for new attachment information to be input from either the AUX connector 39 or the user interface 32. Furthermore, when attachment information is input from either the AUX connector 39 or the user interface 32, the control device 30 may acquire the input attachment information.

[0102] Furthermore, the hydraulic system 100 may be equipped with only one of the input configuration of attachment information via the user interface 32 and the input configuration of attachment information via the AUX connector 39. Furthermore, the control device 30 may acquire attachment information using a procedure and method other than those described above.

[0103] When the control device 30 acquires the attachment information (S1 in FIG. 5), it identifies the attachment 11 attached to the work machine 1 based on the attachment information, and reads out the control data (FIG. 3) corresponding to the identified attachment 11 from the memory 31 (S2). At this time, the control device 30 may read out information corresponding to the acquired attachment information from the memory 31, and identify the attachment 11 based on the read out information. Alternatively, the control device 30 may specify identification information, such as the model number of the attachment 11 corresponding to the acquired attachment information, and read out the control data corresponding to the specified identification information from the memory 31.

[0104] When the driver operates the AUX operation switch 34b to start the attachment 11 that is in a stopped state, a command to start the attachment 11 is input from the AUX operation device 34 to the control device 30 (S3). In response to this command, the control device 30 executes startup current control based on the control data read from the memory 31 (S4).

[0105] In the startup current control, the control device 30 first determines, based on the control data read from the memory 31, which of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B is to be operated when starting up the attachment 11, and determines the target current value Q2 and the switching current value Q1.

[0106] 4, the control device 30 determines the target current value Q2 to be a value higher than the activation point Q1a at which the attachment 11 starts to move. The control device 30 also determines the switching current value Q1 to be a relatively high current value within the current range R2a in which the attachment 11 does not move, and a current value that is smaller than the activation point Q1a by a first predetermined value. The control device 30 also determines the switching current value Q1 to be a value higher than the target current value Q4 (0 [A]) when the attachment 11 is stopped.

[0107] As shown in FIG. 4, the control device 30 then inputs a switching current value Q1 as a step value to the operating AUX electromagnetic control valve, increasing the input current value from 0 [A] to the switching current value Q1 in one go (instantaneously). The control device 30 then ramps the input current value to the operating AUX electromagnetic control valve from the switching current value Q1 to a target current value Q2 based on a predetermined ramp function, gradually increasing the input current value from the switching current value Q1 to the target current value Q2 over a predetermined time T1. At this time, the control device 30 limits the input current value so that the amount of change in the input current value per unit time does not exceed the slope of the predetermined ramp function. That is, the control device 30 gradually increases the input current value to the operating AUX electromagnetic control valve within a current range R1a in which the attachment 11 operates.

[0108] As a result, immediately before the attachment 11 starts to move, the amount of hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 increases suddenly, and the supply pressure of the hydraulic oil rises suddenly. Also, immediately before the attachment 11 starts to move, the amount of hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 gradually increases, and the supply pressure of the hydraulic oil gradually rises. Then, when the input current value to the operating AUX electromagnetic control valve reaches the target current value Q2, the hydraulic actuator 27 and the attachment 11 enter a stable startup state.

[0109] Thereafter, when the driver operates the AUX operation switch 34b to stop the attachment 11 that is in a driving state, a stop command for the attachment 11 is input from the AUX operation device 34 to the control device 30 (S5 in FIG. 5). In response to this, the control device 30 executes stop-time current control based on the control data read from the memory 31 (S6).

[0110] In the stop current control, the control device 30 first determines which of the first AUX electromagnetic control valve 65A and the second AUX electromagnetic control valve 65B is to be operated when stopping the attachment 11, based on control data read from the memory 31, and determines the target current value Q4 and the switching current value Q3. At this time, the control device 30 sets the target current value Q4 to 0 [A], as shown in Fig. 4. The control device 30 also sets the switching current value Q3 to a relatively high current value within a current range R2b in which the attachment 11 does not operate, and which is smaller than the stop point Q3a by a second predetermined value.

[0111] 4, the control device 30 ramps the input current value to the operating AUX solenoid control valve from the drive current value Q2x to the switching current value Q3 based on a predetermined ramp function, and gradually reduces the input current value from the drive current value Q2x to the switching current value Q3 over a predetermined time T2. At this time, the control device 30 limits the input current value so that the amount of current change per unit time of the input current value does not exceed the slope of the predetermined ramp function. Next, the control device 30 steps in a target current value Q4 (0 [A]) as the input current value to the operating AUX solenoid control valve, and reduces the input current value from the switching current value Q3 to the target current value Q4 in one go (instantaneously).

[0112] As a result, the amount of hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 gradually decreases, and the supply pressure of the hydraulic oil gradually drops, until immediately after the attachment 11 stops moving. Immediately after the attachment 11 stops moving, the amount of hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 suddenly decreases, and the supply pressure of the hydraulic oil suddenly drops. Then, when the input current value to the operating AUX electromagnetic control valve reaches the target current value Q4, the hydraulic actuator 27 and the attachment 11 enter a stable stopped state.

[0113] As described above, the control device 30 determines the target current values ​​Q2, Q4 and the switching current values ​​Q1, Q3 for the operating AUX electromagnetic control valves 65A, 65B based on the input attachment information when starting or stopping the attachment 11. When changing the input current value to the operating AUX electromagnetic control valves 65A, 65B to the target current values ​​Q2, Q4, the control device 30 changes the amount of current change per unit time of the input current value before and after the input current value reaches the switching current values ​​Q1, Q3, thereby suppressing a sudden inflow or cessation of the flow of hydraulic oil to the hydraulic actuator 27 of the attachment 11.

[0114] The ramp function used by the control device 30 in the startup current control and shutdown current control is a linear function, but a quadratic function may be used in at least one of the startup current control and shutdown current control to gradually change the input current value to the operating AUX solenoid control valve.

[0115] If the type of attachment 11 is different, the type and number of hydraulic actuators 27 mounted on the attachment 11 will also be different, and therefore at least one of the target current value Q2, switching current values ​​Q1, Q3, drive current value Q2x, and input current value change time (predetermined time) T1, T2 of the operating AUX solenoid control valves 65A, 65B included in the control data will be different.

[0116] For example, as shown in Fig. 6, if the target current values ​​Q2(1) and Q2(2) at startup are different for the first attachment 11 and the second attachment 11, the state of change in the input current value to the active AUX solenoid control valves 65A, 65B will be different when the control device 30 executes the startup current control (S4) and the shutdown current control (S6) of Fig. 5 based on the attachment information, etc. (control data) of the first attachment 11, and when it executes the startup current control and the shutdown current control based on the attachment information, etc. of the second attachment 11. In Fig. 6, the input current value to the active AUX solenoid control valves 65A, 65B when the first attachment 11 is connected to the work machine 1 is indicated by a thick solid line, and the input current value to the active AUX solenoid control valves 65A, 65B when the second attachment 11 is connected to the work machine 1 is indicated by a thick dashed line.

[0117] 6, when the target current value Q2(1) for the first attachment 11 is lower than the target current value Q2(2) for the second attachment 11, the change time T1(1) until the input current value reaches the target current value Q2(1) is shorter than the change time T1(2) until the input current value reaches the target current value Q2(2). Furthermore, the change time T2(1) until the input current value reaches the target current value Q4 when the first attachment 11 is stopped from the drive current value Q2x(1) is shorter than the change time T2(2) until the input current value reaches the target current value Q4 from the drive current value Q2x(2) for the second attachment 11. In this way, the control device 30 differentiates the change times T1(1), T1(2), T2(1), and T2(2) of the input current value to the operating AUX solenoid control valves 65A and 65B based on the attachment information for the attachment 11.

[0118] Furthermore, for example, as shown in FIG. 7, if the switching current values ​​Q1(1), Q3(1) of the first attachment 11 are different from the switching current values ​​Q1(2), Q3(2) of the second attachment 11, the change state of the input current value to the operating AUX solenoid control valves 65A, 65B will be different when the control device 30 executes startup current control and shutdown current control based on the attachment information of the first attachment 11 and when it executes startup current control and shutdown current control based on the attachment information of the second attachment 11.

[0119] As shown in Figure 7, when the switching current value Q1(1) when starting the first attachment 11 is lower than the switching current value Q1(2) when starting the second attachment 11, the change time T1(1) until the input current value when starting the first attachment 11 reaches the target current value Q2 is longer than the change time T2(2) until the input current value when starting the second attachment 11 reaches the target current value Q2.

[0120] Furthermore, if the switching current value Q3(1) when stopping the first attachment 11 is lower than the switching current value Q3(2) when stopping the second attachment 11, the change time T2(1) until the input current value when stopping the first attachment 11 reaches the target current value Q4 will be longer than the change time T2(2) until the input current value when stopping the second attachment 11 reaches the target current value Q4. In this way, the control device 30 varies the change times T1(1), T1(2), T2(1), T2(2) of the input current value to the operating AUX solenoid control valves 65A, 65B based on the attachment information of the attachment 11.

[0121] Furthermore, the control device 30 may vary the slope of the ramp function used in the startup current control and the shutdown current control depending on the type of hydraulic actuator 27 mounted on the attachment 11. The slope of the ramp function corresponds to the amount of change in current per unit time when the input current value to the operating AUX electromagnetic control valves 65A, 65B gradually changes.

[0122] For example, an attachment 11 equipped with a rotary motion hydraulic actuator 27 such as a hydraulic motor is more likely to experience high surge pressure when starting and stopping than an attachment 11 equipped with a linear motion hydraulic actuator 27 such as a hydraulic cylinder. Also, an attachment 11 equipped with a linear motion hydraulic actuator 27 is required to have higher responsiveness than an attachment 11 equipped with a rotary motion hydraulic actuator 27.

[0123] For example, the control device 30 determines the type of attachment 11 attached to the work machine 1 based on the input attachment information. If the control device 30 determines that the attached attachment 11 is an attachment 11 equipped with a rotary motion type hydraulic actuator 27, it uses a ramp function with a relatively gentle slope, for example, as shown by the thick solid line in Fig. 8, for the starting current control and the stopping current control. On the other hand, if the control device 30 determines that the attached attachment 11 is an attachment 11 equipped with a linear motion type hydraulic actuator 27, it uses a ramp function with a relatively steep slope, as shown by the thick dashed line in Fig. 8, for the starting current control and the stopping current control.

[0124] That is, when the control device 30 determines based on the attachment information that the attachment 11 is an attachment equipped with a linear motion type hydraulic actuator 27, it makes the absolute value of the slope of the ramp function used in the startup current control and shutdown current control larger than when the attachment is an attachment equipped with a rotational motion type hydraulic actuator 27.

[0125] Furthermore, as the absolute value of the slope of the ramp function increases, the amount of current change per unit time when the input current value to the operating AUX solenoid control valves 65A, 65B gradually changes increases, and the change time until the input current value reaches the target current values ​​Q2, Q4 (see T1(1), T1(2), T2(1), T2(2) in FIG. 8) becomes shorter. For this reason, the control device 30 changes the slope of the ramp function used in the startup current control and the shutdown current control based on the attachment information, thereby also changing the amount of current change per unit time and the change time of the input current value to the operating AUX solenoid control valves 65A, 65B.

[0126] Specifically, for example, when the attachment 11 determined based on the attachment information is an attachment 11 equipped with a linear motion hydraulic actuator 27, the control device 30 increases the absolute value of the slope of the ramp function, thereby increasing the amount of change per unit time in the input current value to the operating AUX solenoid control valves 65A, 65B and shortening the change time, compared to when the attachment 11 is equipped with a rotary motion hydraulic actuator 27. The slope of the ramp function may be set for each attachment 11 and included in the control data.

[0127] In the work machine 1, the rotation speed of the prime mover (engine) 6 is sometimes reduced to perform work using the work device 4 and the attachment 11. However, when the rotation speed of the prime mover 6 is reduced, the flow rate and pressure of the hydraulic oil discharged from the main pump P2 are reduced, and the flow rate and pressure of the hydraulic oil supplied from the AUX coupler 25 to the hydraulic actuator 27 of the attachment 11 are also reduced, resulting in a slower response when starting or stopping the hydraulic actuator 27 and the attachment 11. To address this, when starting or stopping the attachment 11, the control device 30 may change the slope of a ramp function for ramping the input current value to the operating AUX electromagnetic control valves 65A, 65B, depending on the rotation speed of the prime mover 6 detected by the rotation speed sensor 36 (FIG. 2).

[0128] Fig. 9 is a diagram showing the relationship between the rotation speed of the prime mover 6 and the absolute value of the slope of the ramp function. The control line L1 shown in Fig. 9 indicates that the absolute value of the slope of the ramp function increases as the rotation speed of the prime mover 6 decreases. Data such as an arithmetic expression or a table showing the control line L1 is stored in memory 31 (Fig. 2).

[0129] For example, in the startup current control (S4) of Fig. 5, the control device 30 determines the operating AUX solenoid control valves 65A, 65B, the target current value Q2, and the switching current value Q1, and applies the rotation speed of the prime mover 6 detected by the rotation speed sensor 36 to the control line L1 to determine the slope of the corresponding ramp function, thereby determining the ramp function. Also, in the stop current control (S6) of Fig. 5, the control device 30 determines the operating AUX solenoid control valves 65A, 65B, the target current value Q4, and the switching current value Q3, and applies the rotation speed of the prime mover 6 detected by the rotation speed sensor 36 to the control line L1 to determine the slope of the corresponding ramp function, thereby determining the ramp function.

[0130] In addition, the control device 30 may determine the slope of the ramp function according to the rotation speed of the prime mover 6 while executing the start-up current control or the stop-down current control, and then, when the accelerator device 33 is operated and the rotation speed of the prime mover 6 is changed, change the slope of the ramp function according to the changed rotation speed of the prime mover 6.

[0131] According to the above, as the rotation speed of the prime mover 6 decreases, the absolute value of the slope of the ramp function increases, and the amount of current change per unit time when the input current value to the operating AUX electromagnetic control valves 65A, 65B gradually changes increases. This shortens the time it takes for the input current value to reach the target current values ​​Q2, Q4, improving the responsiveness of starting and stopping the attachment 11. Furthermore, as the rotation speed of the prime mover 6 increases, the absolute value of the slope of the ramp function decreases, and the amount of current change per unit time in the input current value to the operating AUX electromagnetic control valves 65A, 65B decreases. This lengthens the time it takes for the input current value to change to the operating AUX electromagnetic control valves 65A, 65B, reducing impacts when starting and stopping the attachment 11.

[0132] Furthermore, when the work machine 1 is in a low-temperature environment, the temperature of the hydraulic oil drops and the viscosity increases, making it difficult for the hydraulic oil to flow from the AUX coupler 25 to the hydraulic actuator 27 of the attachment 11, resulting in poor responsiveness when starting or stopping the hydraulic actuator 27 and the attachment 11. To address this, the control device 30 may change the slope of the ramp function depending on the temperature of the hydraulic oil detected by the temperature sensor 37 (FIG. 2) when starting or stopping the attachment 11.

[0133] Fig. 10 is a diagram showing the relationship between the temperature of the hydraulic oil in the work machine 1 and the absolute value of the slope of the ramp function. The control line L2 shown in Fig. 10 indicates that the absolute value of the slope of the ramp function increases as the temperature of the hydraulic oil decreases. Data such as an arithmetic formula or a table showing the control line L2 is stored in memory 31.

[0134] For example, in startup current control, the control device 30 determines the operating AUX solenoid control valves 65A, 65B, the target current value Q2, and the switching current value Q1, and applies the hydraulic oil temperature detected by the temperature sensor 37 to the control line L2 to determine the slope of the corresponding ramp function, thereby determining the ramp function.Furthermore, in shutdown current control, the control device 30 determines the operating AUX solenoid control valves 65A, 65B, the target current value Q4, and the switching current value Q3, and applies the hydraulic oil temperature detected by the temperature sensor 37 to the control line L2 to determine the slope of the corresponding ramp function, thereby determining the ramp function.

[0135] According to the above, as the temperature of the hydraulic oil decreases, the absolute value of the slope of the ramp function increases, and the amount of current change per unit time when the input current value to the operating AUX electromagnetic control valves 65A, 65B gradually changes increases. This shortens the time it takes for the input current value to reach the target current values ​​Q2, Q4, improving the responsiveness of starting and stopping the attachment 11. Furthermore, as the temperature of the hydraulic oil increases, the absolute value of the slope of the ramp function decreases, and the amount of current change per unit time in the input current value to the operating AUX electromagnetic control valves 65A, 65B decreases. This lengthens the time it takes for the input current value to change to the operating AUX electromagnetic control valves 65A, 65B, reducing impacts when starting and stopping the attachment 11.

[0136] As described above, control device 30 may determine target current values ​​Q2, Q4 and switching current values ​​Q1, Q3 for each attachment 11 based on the attachment information, and may determine the slope of the ramp function in accordance with at least one of the rotation speed of prime mover 6 and the temperature of the hydraulic oil. Alternatively, control device 30 may perform at least one of the following processes: determining current values ​​Q1 to Q4 based on the attachment information, determining a ramp function based on the rotation speed of prime mover 6, and determining a ramp function based on the temperature of the hydraulic oil.

[0137] If the process of determining the current values ​​Q1 to Q4 based on the attachment information is omitted, the current values ​​Q1 to Q4 may be set to fixed values ​​common to all target attachments 11 equipped with hydraulic actuators 27 usable by the work machine 1 and stored in the memory 31. In this case, the target current value Q2 at startup is set to an input current value for the operating AUX electromagnetic control valves 65A, 65B that corresponds to the maximum flow rate or a predetermined flow rate of hydraulic oil that can be supplied from the AUX control valve 60C to the hydraulic actuators 27 of the attachments 11 via the AUX coupler 25. The target current value Q4 at shutdown is set to 0 [A]. The switching current values ​​Q1 and Q3 are set to relatively high current values ​​within the current ranges of the operating AUX electromagnetic control valves 65A, 65B that do not operate any target attachments 11.

[0138] Alternatively, the target current values ​​Q2 and Q4 may be set to fixed values ​​common to all target attachments 11, and the switching current values ​​Q1 and Q3 may be determined by the control device 30 based on the attachment information.

[0139] Alternatively, for example, when transitioning to the AUX mode, the control device 30 may, as a preliminary process (preparatory process), operate the AUX control valve 60C and the AUX electromagnetic control valves 65A, 65B and determine the switching current values ​​Q1, Q3 based on the pressure of the hydraulic oil detected by at least one of the AUX pressure sensors 38a, 38b and the pressure sensor 48 (Figure 2).

[0140] Specifically, for example, with the attachment 11 attached to the work machine 1 and the hydraulic actuator 27 stopped, the control device 30 increases the input current value to either the first AUX electromagnetic control valve 65A or the second AUX electromagnetic control valve 65B by a predetermined value in a step input manner, supplies hydraulic oil from the AUX control valve 60C to the hydraulic actuator 27 via the AUX coupler 25, and detects the input current value corresponding to when the attachment 11 starts to move, based on the pressure of the hydraulic oil detected by at least one of the AUX pressure sensors 38a, 38b and the pressure sensor 48. The control device 30 then determines the value obtained by subtracting a predetermined value from the detected input current value as the switching current value Q1 at startup.

[0141] Furthermore, for example, while the attachment 11 and the hydraulic actuator 27 are driven, the control device 30 reduces the input current value to either the first AUX electromagnetic control valve 65A or the second AUX electromagnetic control valve 65B using a ramp input to reduce the amount of hydraulic oil supplied from the AUX control valve 60C to the hydraulic actuator 27 via the AUX coupler 25, and detects the input current value corresponding to when the attachment 11 has stopped moving, based on the pressure of the hydraulic oil detected by at least one of the AUX pressure sensors 38a, 38b and the pressure sensor 48. The control device 30 then determines the detected input current value minus a predetermined value as the switching current value Q3 when the attachment 11 has stopped moving.

[0142] In the above-described embodiment, the control device 30 determines the target current value Q2 when activating the attachment 11 based on the attachment information, but the control device 30 may determine or change the target current value Q2 in response to the operation of the AUX volume switch 34c. Specifically, for example, when the driver operates the AUX volume switch 34c from the neutral position (unoperated position) to activate the attachment 11, an operation signal corresponding to the operation is output from the AUX operation device 34. The control device 30 detects the amount of operation of the AUX volume switch 34c based on the operation signal output from the AUX operation device 34, and determines the target current value Q2 based on the amount of operation.

[0143] The control device 30 then inputs a switching current value Q1 as a step value as an input current value to the operating AUX electromagnetic control valve, increasing the input current value from 0 [A] to the switching current value Q1 in one go. The control device 30 then gradually increases the input current value to the operating AUX electromagnetic control valve from the switching current value Q1 to a target current value Q2 determined by operation of the AUX volume switch 34c, based on a predetermined ramp function. At this time, the control device 30 limits the input current value so that the amount of change in the input current value per unit time does not exceed the slope of the predetermined ramp function.

[0144] As another example, the control device 30 may first determine the target current value Q2 for starting the attachment 11 based on the attachment information, and then change the target current value Q2 based on the amount of operation of the AUX volume switch 34c before or while increasing the input current value to the operating AUX electromagnetic control valve. In this case, too, when starting the attachment 11, the control device 30 gradually increases the input current value to the operating AUX electromagnetic control valve from the switching current value Q1 to the changed target current value Q2 based on a predetermined ramp function, and limits the input current value so that the amount of current change per unit time of the input current value does not exceed the slope of the predetermined ramp function.

[0145] In addition, while the attachment 11 is being driven, the control device 30 may change the drive current value Q2x to increase or decrease based on the amount of operation of the AUX volume switch 34c, and may change the input current value to the operating AUX electromagnetic control valve to the changed drive current value Q2x based on a predetermined ramp function.

[0146] The control device 30 may also determine that a command to start the attachment 11 has been input when the AUX volume switch 34c is operated away from the neutral position while the attachment 11 is stopped and the target current value Q2 determined based on the amount of operation of the AUX volume switch 34c is greater than the switching current value Q1. The control device 30 may also determine that a command to stop the attachment 11 has been input when the AUX volume switch 34c is operated back to the neutral position while the attachment 11 is driving and the drive current value Q2x determined based on the amount of operation of the AUX volume switch 34c is smaller than the switching current value Q3. In these cases, the AUX operation switch 34b may be omitted.

[0147] In the above-described embodiment, the control device 30 transitions to the AUX mode when the AUX mode switch 34a is turned on. Alternatively, the control device 30 may automatically transition to the AUX mode when a sensor detects that an external oil passage 26, such as a hose, is connected to the AUX coupler 25.

[0148] In the above-described embodiment, an example has been shown in which the attachment information is input from the user interface 32 or the AUX connector 39, but the attachment information may be input by an input device other than these. For example, a storage medium such as an IC tag, a beacon, a two-dimensional code, or a three-dimensional code that stores the attachment information may be attached to the attachment 11, and the work machine 1 may be provided with a reading device (reader) that reads the attachment information from the storage medium.

[0149] In the above-described embodiment, each process is implemented by a processing circuit including one or more processors and one or more memories, but instead of or in addition to the processing circuit, it may be implemented by an integrated circuit combining at least one of various analog circuits and digital circuits. Furthermore, the processor may be not only a CPU, but also various processors suitable for computer control, such as a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit).

[0150] Furthermore, multiple physically separated processors may cooperate with each other to execute each process, etc. For example, processors installed in multiple physically separated computers may cooperate with each other via a network such as a LAN (Local Area Network), a WAN (Wide Area Network), or the Internet to execute each process, etc. Furthermore, the software program executed by the processor may be installed in memory from a server or the like via a network, or may be distributed in a state stored on a recording medium such as a memory stick or a memory card and installed in the memory of the processing circuit from the recording medium.

[0151] The hydraulic system 100 and the work machine 1 of the present embodiment described above have the following configurations and provide the following effects.

[0152] [Item 1] The hydraulic system 100 includes control valves 65A, 65B (first AUX electromagnetic control valve 65A, second AUX electromagnetic control valve 65B) that adjust the flow rate and pressure of hydraulic oil supplied to the hydraulic actuators 27 that operate the attachment 11 attached to the work machine 1, and a control device 30 that controls the opening of the control valves 65A, 65B by changing the input current value input to the control valves 65A, 65B. The control device 30 changes the input current value up to target current values ​​Q2, Q4 that correspond to the target opening of the control valves 65A, 65B, and gradually changes the input current value within first current ranges R1a, R1b in which the attachment 11 operates when starting or stopping the attachment 11.

[0153] The configuration of item 1 above prevents hydraulic oil from suddenly flowing into or stopping from the hydraulic actuator 27 when starting or stopping the attachment 11, thereby reducing the likelihood of a large shock (vibration) being applied to the attachment 11. Furthermore, since the input current value of the control valves 65A, 65B is gradually changed over first current ranges R1a, R1b, which are a part of the entire current range over which the input current value is changed, this reduces delays in the time it takes for the attachment 11 to start or stop, and also reduces a decrease in start-up or stop responsiveness. This makes it possible to reduce shocks and a decrease in responsiveness when starting or stopping the attachment 11 attached to the work machine 1.

[0154] [Item 2] In the hydraulic system 100 described in Item 1 above, when starting the attachment 11, the control device 30 increases the input current value in one go to a first current value Q1 within the second current range R2a in which the attachment 11 does not operate, and then gradually increases the input current value from the first current value Q1 to a second current value Q2, which is the target current value.

[0155] The configuration described in item 2 above makes it possible to further prevent hydraulic oil from suddenly flowing into the hydraulic actuator 27 when starting up the attachment 11, thereby further reducing the amount of impact that would be applied to the attachment 11. It also makes it possible to prevent a decrease in the responsiveness of the attachment 11 until it starts up.

[0156] [Item 3] The hydraulic system 100 described in Item 2 above is provided with a first input device (AUX operating device) 34 for inputting operation instructions for the attachment 11, and when a start instruction for the attachment 11 is input by the first input device 34, the control device 30 increases the input current value in one go to a first current value Q1, and then gradually increases the input current value from the first current value Q1 to a second current value Q2 over a predetermined time period.

[0157] The configuration of item 3 above makes it possible to further reduce the occurrence of impacts and reduced responsiveness when starting the attachment 11 in response to a user, such as the driver of the work machine 1, inputting an instruction to start the attachment 11 using the first input device 34.

[0158] [Item 4] In the hydraulic system 100 described in the above item 2 or 3, the control device 30 determines the first current value Q1 to be a relatively high value within the second current range R2a.

[0159] With the configuration of item 4 above, when starting the attachment 11, hydraulic oil can be efficiently flowed into the hydraulic actuator 27 until just before the attachment 11 starts moving (just before start-up), and then hydraulic oil can be slowly flowed into the hydraulic actuator 27, making it possible to further suppress the occurrence of impacts and reductions in responsiveness.

[0160] [Item 5] In the hydraulic system 100 described in item 3 or 4 above, the control device 30 determines the first current value Q1 to be a value higher than the target current value Q4 when stopping the attachment 11.

[0161] The configuration of item 5 above allows hydraulic oil to flow efficiently into the hydraulic actuator 27 when starting up the attachment 11, and then allows hydraulic oil to flow slowly into the hydraulic actuator 27, thereby making it possible to suppress the occurrence of impacts and a decrease in responsiveness.

[0162] [Item 6] In the hydraulic system 100 described in any one of items 2 to 5 above, there is provided a second input device 32, 39 (user interface 32, AUX connector 39) for inputting attachment information relating to the attachment 11 attached to the work machine 1, and the control device 30 determines the first current value Q1 based on the attachment information input by the second input device 32, 39.

[0163] The configuration of item 6 above makes it possible to set in the hydraulic system 100 the first current value Q1 that corresponds to the attachment 11 attached to the work machine 1. This effectively prevents hydraulic oil from suddenly flowing into the hydraulic actuator 27 when starting up the attachment 11, making it possible to prevent a large impact from being applied to the attachment 11 and also to prevent a decrease in responsiveness until the attachment 11 is started up.

[0164] [Item 7] In the hydraulic system 100 described in the above item 6, the control device 30 determines the second current value Q2 based on the attachment information input by the second input devices 32, 39.

[0165] By configuring item 7 above, the optimal target current value Q2 at startup corresponding to the attachment 11 attached to the work machine 1 can be set in the hydraulic system 100, allowing the attachment 11 to be started and driven stably and appropriately.

[0166] [Item 8] The hydraulic system 100 described in Item 6 above is provided with an operating device (AUX operating device) 34 including an operating member (AUX volume switch) 34c that is operated to set the flow rate and pressure of the hydraulic oil supplied to the hydraulic actuator 27, and when starting the attachment 11, the control device 30 detects the amount of operation of the operating member 34c based on an operation signal output from the operating device 34 in response to operation of the operating member 34c, and determines the second current value Q2 based on the amount of operation.

[0167] With the configuration of item 8 above, when starting the attachment 11, the user can operate the operating member 34c to arbitrarily set the second current value Q2, which is the target current value, to supply hydraulic oil at a desired flow rate and pressure to the hydraulic actuator 27 of the attachment 11, thereby operating the drive of the attachment 11. Furthermore, even if the second current value Q2 is arbitrarily set by operating the operating member 34c, the control device 30 immediately increases the input current value to the control valves 65A, 65B to the first current value Q1, and then gradually increases it to the arbitrarily set second current value Q2, thereby preventing a large impact from being applied to the attachment 11 and reducing the responsiveness of the attachment 11 until it starts up.

[0168] [Item 9] In the hydraulic system 100 described in Item 1 above, when stopping the attachment 11, the control device 30 gradually reduces the input current value to a third current value Q3 within the second current range R2b in which the attachment 11 does not operate, and then immediately reduces the input current value from the third current value Q3 to a fourth current value Q4, which is the target current value.

[0169] The configuration of item 9 above makes it possible to further prevent hydraulic oil from suddenly ceasing to flow to the hydraulic actuator 27 when stopping the attachment 11, thereby further reducing the likelihood of a large impact being applied to the attachment 11. It also makes it possible to prevent a decrease in responsiveness until the attachment 11 is stopped.

[0170] [Item 10] The hydraulic system 100 described in Item 9 above is provided with a first input device 34 for inputting operation instructions for the attachment 11, and when an instruction to stop the attachment 11 is input via the first input device 34, the control device 30 gradually reduces the input current value to a third current value Q3 over a predetermined time, and then reduces the input current value from the third current value Q3 to a fourth current value Q4 in one go.

[0171] The configuration of the above item 10 makes it possible to further reduce the occurrence of impacts and reduction in responsiveness when stopping the attachment 11 in response to the user inputting an instruction to stop the attachment 11 using the first input device 34.

[0172] [Item 11] In the hydraulic system 100 described in the above item 9 or 10, the control device 30 determines the third current value Q3 to be a relatively high value within the second current range R2b.

[0173] The configuration of the above item 11 prevents the hydraulic oil from suddenly stopping flowing to the hydraulic actuator 27 until immediately after the attachment 11 stops moving (immediately after it has stopped), and then the supply of hydraulic oil to the hydraulic actuator 27 can be immediately stopped, thereby further suppressing the occurrence of impacts and reduced responsiveness.

[0174] [Item 12] In the hydraulic system 100 described in any one of items 9 to 11 above, a second input device 32, 39 is provided for inputting attachment information relating to the attachment 11 attached to the work machine 1, and the control device 30 determines the third current value Q3 based on the attachment information input by the second input device 32, 39.

[0175] The configuration of item 12 above makes it possible to set the third current value Q3 in the hydraulic system 100 according to the attachment 11 attached to the work machine 1. This effectively prevents the flow of hydraulic oil to the hydraulic actuator 27 from suddenly ceasing when the attachment 11 is stopped, making it possible to prevent a large impact from being applied to the attachment 11 and also to prevent a decrease in responsiveness until the attachment 11 is stopped.

[0176] [Item 12] The hydraulic system 100 described in Item 12 above is provided with an operating device 34 including an operating member 34c that is operated to set the flow rate and pressure of hydraulic oil supplied to the hydraulic actuator 27, and when driving the activated attachment 11, the control device 30 detects the amount of operation of the operating member 34c based on an operation signal output from the operating device 34 in response to operation of the operating member 34c, determines a drive current value Q2x based on the amount of operation, and inputs the drive current value Q2x to the control valves 65A, 65B, and gradually reduces the input current value from the drive current value Q2x to a third current value Q3 when stopping the attachment 11.

[0177] With the configuration of item 13 above, the user can operate the operating member 34c while driving the attachment 11 to arbitrarily set the drive current value Q2x input to the control valves 65A, 65B, supply hydraulic oil at a desired flow rate and pressure to the hydraulic actuators 27 of the attachment 11, and operate the drive of the attachment 11. Furthermore, even if the drive current value Q2x is arbitrarily set by operating the operating member 34c, when stopping the attachment 11, the control device 30 gradually reduces the input current value to the control valves 65A, 65B from the drive current value Q2x to the third current value Q3, thereby preventing a large impact from being applied to the attachment 11 and reducing the responsiveness of the attachment 11 until it starts up.

[0178] [Item 14] In the hydraulic system 100 described in any one of items 1 to 13 above, a second input device 32, 39 is provided for inputting attachment information relating to the attachment 11 attached to the work machine 1, and the control device 30 changes at least one of the change times T1, T2 until the input current value reaches the target current values ​​Q2, Q4 and the amount of current change per unit time when the input current value gradually changes, according to the attachment information input by the second input device 32, 39.

[0179] With the configuration of item 14 above, when starting or stopping the attachment 11 attached to the work machine 1, the input current value to the control valves 65A, 65B can be changed to the target current values ​​Q2, Q4 in change times T1, T2 that correspond to the attachment 11, and the input current value to the control valves 65A, 65B can be gradually changed in the first current ranges R1a, R1b by an amount of current change per unit time that corresponds to the attachment 11. Therefore, it is possible to efficiently supply or stop the supply of hydraulic oil to the hydraulic actuator 27, and accurately suppress the occurrence of impacts and a decrease in responsiveness.

[0180] [Item 15] In the hydraulic system 100 described in Item 14 above, the control device 30 determines the type of hydraulic actuator 27 based on the attachment information input by the second input device 32, 39, and changes at least one of the change times T1, T2 and the amount of current change per unit time depending on the type of hydraulic actuator 27.

[0181] With the configuration of item 15 above, when starting or stopping the attachment 11, the input current value to the control valves 65A, 65B can be changed to the target current values ​​Q2, Q4 in change times T1, T2 that correspond to the type of hydraulic actuator 27, and the input current value to the control valves 65A, 65B can be gradually changed in the first current ranges R1a, R1b by an amount of current change per unit time that corresponds to the type of hydraulic actuator 27. Therefore, it is possible to more efficiently supply or stop the supply of hydraulic oil to the hydraulic actuator 27, and more accurately suppress the occurrence of impacts and deterioration of responsiveness.

[0182] [Item 16] In the hydraulic system 100 described in Item 15 above, when the hydraulic actuator 27 is a linear motion hydraulic actuator, the control device 30 performs at least one of shortening the change time and increasing the amount of current change per unit time compared to when the hydraulic actuator 27 is a rotational motion hydraulic actuator.

[0183] The configuration of item 16 above makes it possible to further improve the responsiveness of starting or stopping the attachment 11 when an attachment 11 equipped with a linear motion hydraulic actuator 27 such as a hydraulic cylinder is attached to the work machine 1. Also, when an attachment 11 equipped with a rotary motion hydraulic actuator 27 such as a hydraulic motor is attached to the work machine 1, it is possible to further reduce the surge pressure that occurs when starting or stopping the attachment 11, thereby further suppressing the occurrence of impacts.

[0184] [Item 17] The hydraulic system 100 described in any one of items 1 to 16 above includes a prime mover 6, a hydraulic pump P2 that discharges hydraulic oil using power output from the prime mover 6, and a rotation speed detection device (rotation speed sensor) 36 that detects the rotation speed of the prime mover 6, and when starting or stopping the attachment 11, the control device 30 changes the amount of current change per unit time when the input current value gradually changes, depending on the rotation speed of the prime mover 6 detected by the rotation speed detection device 36.

[0185] With the configuration of item 17 above, when starting or stopping the attachment 11, the input current value to the control valves 65A, 65B can be gradually changed with an efficient amount of current change per unit time that corresponds to the rotation speed of the prime mover 6, thereby making it possible to appropriately suppress the occurrence of impacts and deterioration of responsiveness.

[0186] [Item 18] In the hydraulic system 100 described in the above item 17, the control device 30 increases the amount of change in current per unit time as the rotation speed of the prime mover 6 decreases.

[0187] With the configuration of item 18 above, even if the rotation speed of the prime mover 6 decreases when starting or stopping the attachment 11, the input current value to the control valves 65A, 65B can be gradually changed with an efficient amount of current change per unit time that corresponds to the rotation speed of the prime mover 6, thereby making it possible to suppress the occurrence of impacts and a decrease in responsiveness.

[0188] [Item 19] The hydraulic system 100 described in any one of items 1 to 18 above is provided with a temperature detection device (temperature sensor) 37 that detects the temperature of the hydraulic oil, and when starting or stopping the attachment 11, the control device 30 changes the amount of current change per unit time when the input current value gradually changes, depending on the temperature of the hydraulic oil detected by the temperature detection device 37.

[0189] With the configuration of item 19 above, when starting or stopping the attachment 11, the input current value to the control valves 65A, 65B can be gradually changed with an efficient amount of current change per unit time that corresponds to the temperature of the hydraulic oil, thereby making it possible to appropriately suppress the occurrence of impacts and a decrease in responsiveness.

[0190] [Item 20] In the hydraulic system 100 described in the above item 19, the control device 30 increases the amount of change in current per unit time as the temperature of the hydraulic oil decreases.

[0191] With the configuration of item 20 above, when starting or stopping the attachment 11, even if the temperature of the hydraulic oil is low, the input current value to the control valves 65A, 65B can be gradually changed by an amount of current change per unit time that corresponds to the temperature of the hydraulic oil, thereby making it possible to suppress the occurrence of impacts and a decrease in responsiveness.

[0192] [Item 21] The work machine 1 includes a coupling device (hitch) 24 for coupling the attachment 11, and the hydraulic system 100 described in any one of Items 1 to 20.

[0193] The configuration of the above item 21 makes it possible to suppress the occurrence of shocks and the deterioration of responsiveness when starting or stopping the attachment 11 attached to the work machine 1 via the connecting device 24.

[0194] Although the present invention has been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0195] 1 Work equipment 6. Prime Mover 11 Attachment 24 Hitch (coupling device) 27 Hydraulic Actuator 30 Control device 32 User Interface (Second Input Device) 34 AUX operation device (first input device, operation device) 34c AUX volume switch (operating part) 36 Rotational speed sensor (rotational speed detection device) 37 Temperature sensor (temperature detection device) 38a, 38b AUX pressure sensor (pressure detection device) 39 AUX connector (second input device) 48 Pressure sensor (pressure detection device) 65A 1st AUX solenoid control valve (control valve) 65B 2nd AUX solenoid control valve (control valve) 100 Hydraulic System P2 Main pump (hydraulic pump) Q1 Switching current value (first current value) Q2 Target current value (second current value) Q3 Switching current value (third current value) Q4 Target current value (fourth current value) R1a Current range in which the attachment operates at startup (first current range) R1b Current range in which the attachment operates when stopped (first current range) R2a Current range in which the attachment does not operate at startup (second current range) R2b Current range in which attachments do not operate when stopped (second current range) T1, T2, T1(1), T1(2), T2(1), T2(2) Predetermined time, change time

Claims

1. a control valve that adjusts the flow rate and pressure of hydraulic oil supplied to a hydraulic actuator that operates an attachment attached to the work machine; a control device that controls the opening degree of the control valve by changing an input current value input to the control valve; Equipped with the control device changes the input current value up to a target current value corresponding to a target opening of the control valve, and when starting or stopping the attachment, gradually changes the input current value within a first current range in which the attachment operates.

2. 2. The hydraulic system according to claim 1, wherein, when starting the attachment, the control device increases the input current value in one go to a first current value within a second current range at which the attachment does not move, and then gradually increases the input current value from the first current value to a second current value that is the target current value.

3. a first input device for inputting an operation instruction for the attachment; 3. The hydraulic system according to claim 2, wherein when a command to start the attachment is input by the first input device, the control device increases the input current value in one go to the first current value, and then gradually increases the input current value from the first current value to the second current value over a predetermined time period.

4. The hydraulic system according to claim 2 , wherein the control device determines the first current value to be a relatively high value within the second current range.

5. The hydraulic system according to claim 3 , wherein the control device determines the first current value to be a value higher than the target current value when the attachment is stopped.

6. a second input device for inputting attachment information relating to the attachment attached to the work machine; The hydraulic system according to claim 2 , wherein the control device determines the first current value based on the attachment information input by the second input device.

7. The hydraulic system according to claim 6 , wherein the control device determines the second current value based on the attachment information input by the second input device.

8. an operating device including an operating member that is operated to set the flow rate and pressure of the hydraulic oil to be supplied to the hydraulic actuator; 7. The hydraulic system according to claim 6, wherein, when starting the attachment, the control device detects an amount of operation of the operating member based on an operation signal output from the operating device in response to operation of the operating member, and determines the second current value based on the amount of operation.

9. 2. The hydraulic system according to claim 1, wherein, when stopping the attachment, the control device gradually reduces the input current value to a third current value within a second current range at which the attachment does not move, and then reduces the input current value in one go from the third current value to a fourth current value that is the target current value.

10. a first input device for inputting an operation instruction for the attachment; 10. The hydraulic system according to claim 9, wherein, when a command to stop the attachment is input by the first input device, the control device gradually reduces the input current value to the third current value over a predetermined time, and then reduces the input current value from the third current value to the fourth current value in one go.

11. The hydraulic system according to claim 9 , wherein the control device determines the third current value to be a relatively high value within the second current range.

12. a second input device for inputting attachment information relating to the attachment attached to the work machine; The hydraulic system according to claim 9 , wherein the control device determines the third current value based on the attachment information input by the second input device.

13. an operating device including an operating member that is operated to set the flow rate and pressure of the hydraulic oil to be supplied to the hydraulic actuator; The control device When driving the activated attachment, an operation amount of the operating member is detected based on an operation signal output from the operating device in response to operation of the operating member, a drive current value is determined based on the operation amount, and the drive current value is input to the control valve; The hydraulic system according to claim 12, wherein the input current value is gradually reduced from the drive current value to the third current value when the attachment is stopped.

14. a second input device for inputting attachment information relating to the attachment attached to the work machine; 2. The hydraulic system according to claim 1, wherein the control device changes at least one of a time period required for the input current value to reach the target current value and an amount of current change per unit time when the input current value gradually changes, in accordance with the attachment information input by the second input device.

15. 15. The hydraulic system according to claim 14, wherein the control device determines a type of the hydraulic actuator based on the attachment information input by the second input device, and changes at least one of the change time and the amount of current change per unit time depending on the type of the hydraulic actuator.

16. 16. The hydraulic system according to claim 15, wherein the control device, when the hydraulic actuator is a linear motion hydraulic actuator, at least one of shortening the change time and increasing the amount of current change per unit time compared to when the hydraulic actuator is a rotary motion hydraulic actuator.

17. The prime mover and a hydraulic pump that discharges the hydraulic oil using power output from the prime mover; a rotation speed detection device for detecting the rotation speed of the prime mover; Equipped with 2. The hydraulic system according to claim 1, wherein the control device, when starting or stopping the attachment, changes the amount of current change per unit time when the input current value gradually changes, in accordance with the rotation speed of the prime mover detected by the rotation speed detection device.

18. 18. The hydraulic system according to claim 17, wherein the control device increases the amount of change in current per unit time as the rotation speed of the prime mover decreases.

19. a temperature detection device for detecting the temperature of the hydraulic oil; 2. The hydraulic system according to claim 1, wherein the control device, when starting or stopping the attachment, changes the amount of current change per unit time when the input current value gradually changes, in accordance with the temperature of the hydraulic oil detected by the temperature detection device.

20. The hydraulic system according to claim 19, wherein the control device increases the amount of change in current per unit time as the temperature of the hydraulic oil decreases.

21. a coupling device for coupling the attachment; A hydraulic system according to any one of claims 1 to 20; A work machine equipped with

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