Control device for construction machine and construction machine including the same

Abstract

To provide a control device for a construction machine capable of stopping an actuator while suppressing the occurrence of a shock during neutral operation, and a construction machine equipped with the same.SOLUTION: The control device 100A includes the operation lever 41, the boom cylinder 20, the boom control valve 12, the first and second proportional valves 121, 122, and the controller 50. In the boom control valve 12, the meter-in opening for supplying the hydraulic oil to the boom cylinder 20 is set to be closed earlier than the meter-out opening for receiving the hydraulic oil from the boom cylinder 20 at the time of the stop operation. When the operation lever 41 receives a stop operation for stopping the boom 4, the control unit 50 inputs a command signal to the proportional valve while generating a delay in the command signal with respect to the operation amount of the stop operation.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a construction machine and a construction machine equipped with the same. [Background technology]

[0002] A conventional hydraulic excavator (construction machine) has been known that includes a machine body, a boom that can be raised and lowered relative to the machine body, a hydraulic pump that discharges hydraulic oil, a boom cylinder that extends and retracts to raise and lower the boom by receiving hydraulic oil from the hydraulic pump, and a control valve (flow control valve) that is interposed between the hydraulic pump and the boom cylinder and switches the supply path of hydraulic oil to the boom cylinder. The boom cylinder includes a head chamber and a rod chamber, and extends by receiving hydraulic oil from the hydraulic pump into the head chamber, thereby rotating the boom in an upright direction, and contracts by receiving hydraulic oil into the rod chamber, thereby rotating the boom in a lowering direction.

[0003] Patent Document 1 discloses a technology for slowing down the retraction speed of the boom cylinder by adjusting the discharge flow rate of pilot oil discharged from the pilot pressure chamber of the control valve to decrease when the operator returns the boom operating lever from a specified drive position to the neutral position (neutral operation). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-242336 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology described in Patent Document 1 has a problem in that shocks are likely to occur when the boom cylinder decelerates during a neutral operation. Specifically, the technology described above delays the spool's return to the neutral position by controlling the return flow rate (meter-out flow rate) of pilot oil discharged from the pilot pressure chamber of the control valve when the spool of the control valve returns to its neutral position during a neutral operation. In this case, the spool volume, which corresponds to the product of the spool movement amount and the cross-sectional area of ​​the pilot oil chamber, serves as the source of the return flow rate. However, because the spool volume and the opening that controls the flow rate in the control valve are small, the flow rate is easily affected by oil temperature, making it difficult to control the spool movement with high precision. As a result, there is a problem in that shocks are likely to occur due to variations in control.

[0006] An object of the present invention is to provide a control device for a construction machine that is capable of stopping an actuator while suppressing the occurrence of shock during a stopping operation, and a construction machine equipped with the same. [Means for solving the problem]

[0007] The present invention provides a control device for a construction machine having a movable member. The control device includes a hydraulic pump, an operating unit that receives an operation to move the movable member, an actuator that receives a supply of hydraulic oil from the hydraulic pump and moves the movable member, a supply-side valve mechanism that includes a supply port for hydraulic oil from the hydraulic pump to the actuator and is capable of changing the aperture of the supply port, a recovery-side valve mechanism that includes a recovery port for hydraulic oil from the actuator and is capable of changing the aperture of the recovery port, a valve drive unit that is capable of changing the aperture of the supply port and the recovery port in response to an input command signal, and a control unit that inputs the command signal to the valve drive unit so that the supply port and the recovery port open at apertures corresponding to the operation, and when the operation is a stop operation to stop the movable member, inputs the command signal to the valve drive unit so that the recovery port closes at a timing delayed from the relationship between the operation and the apertures. The supply-side valve mechanism and the recovery-side valve mechanism are configured so that the supply port closes before the recovery port in response to the stop operation.

[0008] According to this configuration, when the operating lever is operated to stop, the control unit inputs a command signal to the valve drive unit with a delay, thereby applying a gentle brake to the actuator and stopping the actuator. As a result, the stop control of the movable member can be performed stably and smoothly. Furthermore, since the supply-side valve mechanism and the recovery-side valve mechanism have regions where the supply port closes first and only the recovery port opens in response to the stop operation, pressure is prevented from being applied through the supply port of the supply-side valve mechanism during the stop operation, preventing shock caused by the pressure.

[0009] In the above configuration, it is desirable that, when the supply port is closed and the recovery port is open in response to the stop operation, the control unit inputs the command signal to the valve drive unit so that the recovery port closes at a timing that is delayed compared to the relationship between the operation and the opening degree.

[0010] According to this configuration, by delaying the command signal input by the control unit to the valve drive unit in accordance with the region where the supply port of the supply-side valve mechanism is closed, it is possible to stop the actuator while applying a gentle brake stably to the actuator.

[0011] In the above configuration, it is desirable that the control unit further includes a speed detection unit capable of detecting the drive speed of the actuator, and that the control unit inputs the command signal to the valve drive unit so that the recovery port closes at a later timing than the relationship between the operation and the opening degree the greater the drive speed detected by the speed detection unit when the operating unit receives the stop operation.

[0012] With this configuration, when the actuator drive speed is high and the flow rate of hydraulic oil discharged from the actuator is large, the brakes are applied more gently, thereby reliably suppressing the occurrence of shock. Also, when the actuator drive speed is low, the flow rate of hydraulic oil discharged is small and shock is less likely to occur, so the actuator can be stopped quickly.

[0013] In the above configuration, it is desirable to further include a check valve that is arranged between the supply-side valve mechanism and the recovery-side valve mechanism and the actuator, and that allows hydraulic oil to be supplied from the tank to the actuator when negative pressure is created in the actuator.

[0014] With this configuration, even if the actuator becomes under negative pressure because the supply port of the supply-side valve mechanism closes first, hydraulic oil can be supplied to the actuator through the check valve, thereby suppressing pressure fluctuations in the actuator and further reducing the occurrence of shock.

[0015] In the above configuration, it is desirable to further include an auxiliary valve mechanism that is arranged between the supply-side valve mechanism and the recovery-side valve mechanism and the hydraulic pump, opens to adjust the flow rate of hydraulic oil supplied to an actuator different from the actuator, and is capable of supplying hydraulic oil to the actuator through the supply port.

[0016] With this configuration, even when a combined operation is being performed via the actuator and another actuator, the supply port closes first, thereby avoiding the auxiliary valve mechanism from exerting pressure on the supply-side valve mechanism, and allowing the actuator to be stopped gently.

[0017] In the above configuration, the movable member is a boom supported on the machine body so as to be able to be raised and lowered, and the actuator is a hydraulic cylinder having a cylinder body and a cylinder rod that divides the cylinder body into a head chamber and a rod chamber and is movable relative to the cylinder body, and when the hydraulic cylinder receives hydraulic oil into the head chamber through the supply-side valve mechanism and discharges hydraulic oil from the rod chamber, the cylinder rod extends relative to the cylinder body so as to rotate the boom in an upright direction, and when the hydraulic cylinder receives hydraulic oil into the rod chamber through the supply-side valve mechanism, the cylinder rod extends relative to the cylinder body so as to rotate the boom in an upright direction. When hydraulic oil is discharged from the head chamber, the cylinder rod contracts relative to the cylinder body so as to rotate the boom in a lowering direction, and the operating unit can be operated to an erection region for erecting the boom, a lowering region for lowering the boom, and a neutral region for stopping the raising and lowering of the boom, and when the operating unit is operated from the lowering region to the neutral region as the stop operation, it is desirable that the control unit inputs the command signal to the valve drive unit so that the recovery port closes at a timing delayed from the relationship between the operation and the opening degree.

[0018] With this configuration, even in a configuration in which a stop operation is input during a boom lowering operation and shock to the hydraulic cylinder is likely to occur due to the weight of the boom, the control unit can input a delay in the command signal to the valve drive unit, thereby applying a gentle brake to the hydraulic cylinder and stopping the hydraulic cylinder.As a result, stop control during the boom lowering operation can be performed stably and smoothly.

[0019] In the above configuration, when the operating unit is operated from the lying-down region to the neutral region as the stop operation and then further operated from the neutral region to the standing region, it is desirable that the control unit inputs the command signal to the valve drive unit so that the recovery port closes and then the supply port and the recovery port open based on the relationship.

[0020] According to this configuration, when an operation to perform a boom raising operation is input following the halt of the boom lowering operation, it is possible to avoid applying gentle brakes and quickly transition to the boom raising operation.

[0021] The above configuration may further include a control valve that functions as the supply-side valve mechanism and the recovery-side valve mechanism, the control valve having at least one spool that moves to change the opening of the supply port and the recovery port, the valve drive unit moving the at least one spool by an amount corresponding to the input command signal so as to change the opening of the supply port and the recovery port, and the control valve configured such that the movement of the at least one spool causes the supply port to close before the recovery port.

[0022] According to this configuration, the supply port can be closed before the recovery port by simply moving the spool of the control valve with the valve driving section.

[0023] In the above configuration, it is desirable that the valve drive unit include: a pair of pilot ports provided in the control valve and receiving a pilot pressure for moving the spool; and a pair of proportional valves that receive the command signal from the control unit and open to adjust the pilot pressure acting on the pair of pilot ports in accordance with the command signal.

[0024] According to this configuration, by providing a delay in the command signals input by the control unit to the pair of proportional valves, it is possible to stop the hydraulic cylinders while applying a gentle brake to the hydraulic cylinders.

[0025] In the above configuration, it is preferable that the valve driving portion includes a pair of solenoids that receive the command signal from the control portion and move the spool in response to the command signal.

[0026] According to this configuration, by providing a delay in the command signal that the control unit inputs to the pair of solenoids, it is possible to stop the hydraulic cylinder while applying a gentle brake to the hydraulic cylinder.

[0027] The present invention also provides a construction machine comprising a machine body, a movable member supported by the machine body, and the construction machine control device described above.

[0028] According to this configuration, in a construction machine, it is possible to stop the actuator while preventing shocks from occurring when a stopping operation is performed on a movable member. [Effects of the Invention]

[0029] According to the present invention, it is possible to provide a control device for a construction machine that is capable of stopping an actuator while preventing shocks from occurring during a stopping operation, and a construction machine equipped with the same. [Brief explanation of the drawings]

[0030] [Figure 1]1 is a side view showing a construction machine equipped with a control device according to an embodiment of the present invention. [Figure 2] 1 is a hydraulic circuit diagram of a control device according to an embodiment of the present invention. [Figure 3] FIG. 2 is an enlarged view of a portion of a hydraulic circuit diagram of the control device according to the embodiment of the present invention. [Figure 4] 4 is a graph showing the opening areas of the meter-in opening and the meter-out opening relative to the amount of movement of the spool of the control valve of the control device according to one embodiment of the present invention. [Figure 5] 4 is a flowchart of control executed by a control device according to an embodiment of the present invention during a stop operation. [Figure 6] 10 is a graph showing the relationship between the amount of operation of the control lever and the target flow rate to the boom cylinder in a construction machine equipped with a control device according to one embodiment of the present invention. [Figure 7] 4 is a graph showing the relationship between a target flow rate and a valve opening degree in a construction machine equipped with a control device according to an embodiment of the present invention. [Figure 8] 4 is a graph showing the time transition of a command current during a stopping operation in a construction machine equipped with a control device according to an embodiment of the present invention. [Figure 9] 10 is a graph showing the relationship between the actuator speed and the time constant when a stop determination is made in a construction machine equipped with a control device according to an embodiment of the present invention. [Figure 10] 6 is a graph showing the time progression of the lever operation amount, cylinder pressure, meter-out opening, and cylinder speed in a construction machine equipped with a control device according to one embodiment of the present invention. [Figure 11] 6 is a graph showing the time progression of the lever operation amount, cylinder pressure, meter-out opening, and cylinder speed in a construction machine equipped with a control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[0032] FIG. 1 shows a hydraulic excavator 100 (construction machine) equipped with a control device 100A (FIG. 2) according to one embodiment of the present invention. The hydraulic excavator 100 includes a crawler-type undercarriage 1 capable of traveling on a traveling surface (ground surface G), an upper rotating body 2 mounted on the undercarriage 1 so as to be rotatable about a central axis of rotation perpendicular to the traveling surface, and a work attachment 3 mounted on the upper rotating body 2. The work attachment 3 includes a boom 4 (movable member) supported on the upper rotating body 2 so as to be able to rise and fall, an arm 5 rotatably connected to the tip of the boom 4, and a bucket 6 rotatably connected to the tip of the arm 5. The upper rotating body 2 includes a rotating frame 2S and a cab 2A. The undercarriage 1 and the upper rotating body 2 together constitute a machine body of the present invention.

[0033] The hydraulic excavator 100 includes a boom cylinder 7 (actuator) that operates to raise and lower the boom 4 relative to the upper rotating body 2, an arm cylinder 8 (another actuator) that operates to rotate the arm 5 relative to the boom 4, and a bucket cylinder 9 that operates to rotate the bucket 6 relative to the arm 5. Each cylinder receives hydraulic oil from a hydraulic pump and operates to extend and retract.

[0034] Fig. 2 is a hydraulic circuit diagram of a control device 100A according to this embodiment. Fig. 3 is an enlarged view of a portion of the hydraulic circuit in Fig. 2. As shown in Fig. 2, the control device 100A includes a hydraulic pump 10 connected to an engine (not shown), an arm control valve 11, a boom control valve 12, a boom cylinder 20 constituting the boom cylinder 7 described above, a speed detection unit 25, protection circuits 31 and 32, a boom operation unit 40, and a control unit 50. Fig. 2 shows a portion of the hydraulic circuit that drives the boom cylinder 20 in Fig. 1, and the other hydraulic circuits are not shown.

[0035] The hydraulic pump 10 mainly discharges hydraulic oil for operating the boom cylinder 7 and the arm cylinder 8. The hydraulic pump 10 is driven by an engine (not shown) mounted on the hydraulic excavator 100.

[0036] In this embodiment, the hydraulic pump 10 is a variable displacement hydraulic pump. In other words, the hydraulic pump 10 has a proportional valve (not shown). The proportional valve opens in response to a command signal received from the control unit 50, and adjusts the discharge amount (displacement) of the hydraulic pump 10.

[0037] The boom cylinder 20 receives a supply of hydraulic oil discharged by the hydraulic pump 10 and extends and retracts to raise (move) the boom 4. In this embodiment, the boom cylinder 20 corresponds to the boom cylinder 7 in FIG. 1. The boom cylinder 20 has a cylinder body 21 and a cylinder rod 22 that includes a piston portion 23 that divides the cylinder body 21 into a head chamber 20H and a rod chamber 20R and is movable relative to the cylinder body 21. The tip of the cylinder rod 22 is connected to the boom 4 via a link mechanism (not shown). The boom cylinder 20 can extend to raise the boom 4 (boom-raising operation) by receiving hydraulic oil discharged by the hydraulic pump 10 into the head chamber 20H via the boom control valve 12 and discharging hydraulic oil from the rod chamber 20R, while it can retract to lower the boom 4 (boom-lowering operation) by receiving hydraulic oil discharged by the hydraulic pump 10 into the rod chamber 20R and discharging hydraulic oil from the head chamber 20H.

[0038] The speed detection unit 25 is capable of detecting the drive speed of the boom cylinder 20. Specifically, the speed detection unit 25 detects the extension / contraction speed of the cylinder rod 22 relative to the cylinder body 21, and inputs a signal corresponding to the detected speed to the control unit 50. In other words, the speed detection unit 25 detects the drive speed of the boom 4.

[0039] Boom control valve 12 (supply-side valve mechanism and recovery-side valve mechanism) is disposed so as to be interposed between hydraulic pump 10 and boom cylinder 20, and has a spool that moves to change (control) the flow rate and flow path of hydraulic oil supplied from hydraulic pump 10 to boom cylinder 20. Specifically, boom control valve 12 mainly operates to supply hydraulic oil from hydraulic pump 10 to boom cylinder 20 and to discharge hydraulic oil discharged from boom cylinder 20 to a tank (not shown) when boom 4 performs a boom-up operation and a boom-down operation. Boom control valve 12 is a pilot-operated three-position directional control valve having a pair of pilot ports 12A, 12B.

[0040] When no pilot pressure is input to either of the pair of pilot ports, the boom control valve 12 is maintained in a neutral position, and isolates communication between the hydraulic pump 10 and the boom cylinder 20 .

[0041] When boom lowering pilot pressure is input to first pilot port 12A, boom control valve 12 is switched from the neutral position to the boom lowering position at a stroke corresponding to the magnitude of the boom lowering pilot pressure. This opens the valve to allow hydraulic oil to be supplied from hydraulic pump 10 to rod chamber 20R of boom cylinder 20 at a flow rate corresponding to the stroke, and to allow hydraulic oil to be discharged from head chamber 20H of boom cylinder 20. This drives boom cylinder 20 in the boom lowering direction at a speed corresponding to the boom lowering pilot pressure.

[0042] When boom-raising pilot pressure is input to second pilot port 12B, boom control valve 12 is switched from the neutral position to the boom-raising position at a stroke corresponding to the magnitude of the boom-raising pilot pressure. This opens the valve to allow hydraulic oil to be supplied from hydraulic pump 10 to head chamber 20H of boom cylinder 20 at a flow rate corresponding to the stroke, and to allow hydraulic oil to be discharged from rod chamber 20R of boom cylinder 20. This drives boom cylinder 20 in the boom-raising direction at a speed corresponding to the boom-raising pilot pressure.

[0043] The arm control valve 11 is interposed between the hydraulic pump 10 and the arm cylinder 8, and opens and closes to change the flow rate of hydraulic oil supplied from the arm control valve 11 to the arm cylinder 8. Specifically, the arm control valve 11 is a pilot-operated three-position directional control valve having a pair of pilot ports. The arm control valve 11 functions as a control valve for the arm retraction operation. As shown in FIG. 2, a portion of the hydraulic oil that has passed through the arm cylinder 8 can be supplied to the boom control valve 12. As a result, during combined operation in which the boom 4 and the arm 5 are driven simultaneously, hydraulic oil is supplied from the arm control valve 11 to the boom control valve 12 in addition to the hydraulic pump 10, thereby increasing the drive speed of the boom cylinder 20.

[0044] Boom operating unit 40 is disposed in cab 2A and receives various operations from the operator for operating boom 4. Note that operating units (not shown) for operating arm 5 and bucket 6 are also disposed in cab 2A.

[0045] The boom operation unit 40 receives boom lowering operations and boom raising operations to respectively cause the boom 4 to perform boom lowering operations and boom raising operations. Specifically, the boom operation unit 40 has an operation lever 41 (operation unit) that receives operations to move the boom 4, and an operation command unit 42.

[0046] The control lever 41 is a member that can rotate in response to the boom lowering operation and the boom raising operation by the operator. The boom lowering operation and the boom raising operation are operations that rotate the control lever 41 in opposite directions to each other. Specifically, the control lever 41 can be operated to a raising region (boom raising operation region) for rotating the boom 4 in the raising direction, a lowering region (boom lowering operation region) for rotating the boom 4 in the lowering direction, and a neutral region that is located between the raising region and the lowering region and that stops the raising or lowering of the boom 4.

[0047] The operation command unit 42 inputs a command signal corresponding to the boom-raising operation and the boom-lowering operation applied to the control lever 41 to the control unit 50 in response to the operation. The command signal includes information corresponding to the direction and amount of operation of the control lever 41.

[0048] The control device 100A further includes a first proportional valve 121 and a second proportional valve 122. The first proportional valve 121 and the second proportional valve 122 open so that a pilot pressure (secondary pressure) corresponding to the operation input to the operation lever 41 of the boom operation unit 40 acts on pilot ports 12A and 12B of the boom control valve 12, respectively, by pilot oil supplied from a pilot pump (not shown). The opening degrees of the first proportional valve 121 and the second proportional valve 122 are adjusted by a proportional signal input from the control unit 50. As a result, the pilot pressure can be directly controlled with high accuracy.

[0049] The pair of pilot ports 12A, 12B of the boom control valve 12 and the first and second proportional valves 121 and 122 constitute a valve drive unit in this embodiment. The valve drive unit moves the spool of the boom control valve 12 by an amount corresponding to an input command signal, thereby changing the opening degrees of the meter-in opening and the meter-out opening. That is, the pair of pilot ports 12A, 12B are provided in the boom control valve 12 and receive pilot pressure for moving the spool. Furthermore, the first proportional valve 121 and the second proportional valve 122 (both are proportional valves) receive a command signal from the control unit 50 and open to adjust the pilot pressure for the pair of pilot ports 12A, 12B in accordance with the command signal.

[0050] 2 and 3, protection circuits 31 and 32 each include a relief valve 35 and a check valve 36. Circuit end A in FIG. 3 is connected to boom control valve 12 in FIG. 2, and circuit end B is connected to rod chamber 20R or head chamber 20H of boom cylinder 20 in FIG. 2. When rod chamber 20R or head chamber 20H of boom cylinder 20 becomes negative pressure, check valve 36 allows hydraulic oil from tank T to flow into the chamber with negative pressure and prevents hydraulic oil from flowing in the reverse direction. Relief valve 35 discharges a portion of hydraulic oil to tank T when the pressure in rod chamber 20R or head chamber 20H exceeds a predetermined threshold. In other words, protection circuits 31 and 32 correspond to anti-cavitation overload relief valves.

[0051] The control unit 50 inputs command signals to the first proportional valve 121 and the second proportional valve 122 in accordance with the operation direction and operation amount input to the operation lever 41 of the boom operation unit 40, and drives the boom cylinder 20. Furthermore, in this embodiment, when a stop operation (neutral operation) for the boom lowering operation is input to the operation lever 41, the control unit 50 executes shock mitigation control under predetermined conditions.

[0052] The control unit 50 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a control program, a RAM (Random Access Memory) used as a work area for the CPU, and the like. The control unit 50 functions to have functional units, such as a calculation unit 501, a determination unit 502, and a storage unit 503, as a result of the CPU executing the control program stored in the ROM. These functional units do not have physical entities, but correspond to units of functions executed by the control program. Note that all or part of the control unit 50 is not limited to being provided within the hydraulic excavator 100, and may be located in a location different from the hydraulic excavator 100 when the hydraulic excavator 100 is remotely controlled. Furthermore, the control program may be transmitted from a remote server (management device) or cloud to the control unit 50 in the hydraulic excavator 100 and executed therein, or the control program may be executed on the server or cloud, and various command signals generated may be transmitted to the hydraulic excavator 100.

[0053] The calculation unit 501 executes calculation processes required for various processes executed by the control unit 50. The determination unit 502 executes determination processes required for various processes executed by the control unit 50. The storage unit 503 stores parameters and thresholds required for various processes executed by the control unit 50.

[0054] The boom control valve 12 described above includes a valve body having a supply port for hydraulic oil from the hydraulic pump 10 to the boom cylinder 20 and a recovery port for hydraulic oil from the boom cylinder 20, and the spool that moves relative to the valve body to change the openings of the supply port and the recovery port. Here, the supply port is also referred to as a meter-in opening, and the recovery port is also referred to as a meter-out opening. That is, in this embodiment, the boom control valve 12 functions as both a supply-side valve mechanism that includes a supply port for hydraulic oil from the hydraulic pump 10 to the boom cylinder 20 and is capable of changing the opening of the supply port, and a recovery-side valve mechanism that includes a recovery port for hydraulic oil from the boom cylinder 20 and is capable of changing the opening of the recovery port. In addition, the control unit 50 inputs command signals to the first proportional valve 121 and the second proportional valve 122 (valve drive units) so that the meter-out opening and the meter-in opening are opened at openings corresponding to a preset operation of the operating lever 41. However, when the operation is a stop operation for stopping the boom cylinder 20, the command signal is input to the valve drive unit so that the meter-out opening closes at a timing that is delayed from the predetermined relationship between the operation and the opening degree.

[0055] FIG. 4 is a graph showing the opening areas of the meter-in opening and the meter-out opening relative to the movement amount (stroke amount) of the spool of the boom control valve 12 of the control device 100A according to this embodiment. Note that in FIG. 4, the units of the stroke amount and the opening area are non-dimensional. In this embodiment, when the operating lever 41 is operated in the boom lowering direction, the spool of the boom control valve 12 moves so that the spool stroke amount in FIG. 4 gradually increases from zero. In this case, the boom control valve 12 is set so that the meter-out opening opens first in the spool stroke amount range of 2 to 4, and the meter-in opening opens later when the spool stroke amount becomes 4 or greater. Conversely, when the operating lever 41 is operated toward the neutral position during boom lowering and the spool stroke amount changes toward zero, the meter-in opening of the boom control valve 12 closes first and the meter-out opening closes later. As such, in this embodiment, when the operating lever 41 is operated to the neutral position (stop operation), there is a state in which the meter-in opening is closed and only the meter-out opening is open.

[0056] Fig. 5 is a flowchart of control executed by the control device 100A according to this embodiment during neutral operation. Fig. 6 is a graph showing the relationship between the operation amount of the control lever 41 and the target flow rate to the boom cylinder 20 in a hydraulic excavator 100 equipped with the control device 100A. Fig. 7 is a graph showing the relationship between the target flow rate and the valve opening of the boom control valve 12 in a hydraulic excavator 100 equipped with the control device 100A. Fig. 8 is a graph showing the time transition of the command current to the first proportional valve 121 during neutral operation in the hydraulic excavator 100.

[0057] 4, when the control device 100A starts the control flow, the determination unit 502 of the control unit 50 determines whether or not an operation of the boom 4 has been input (ON) to the operation lever 41 (step S1). Here, if an operation has been input to the operation lever 41 (YES in step S1), the calculation unit 501 of the control unit 50 calculates the target flow rate Q of the hydraulic pump 10 to realize the operation input to the operation lever 41. T(Step S2). In this embodiment, the relationship between the lever operation amount and the target flow rate Q shown in FIG. 6 is stored in advance in the storage unit 503. This relationship is set so that, for example, the greater the operation of the control lever 41 in the boom-down direction, the greater the target flow rate Q of the hydraulic oil supplied to the boom cylinder 20. Therefore, the calculation unit 501 can determine the target flow rate Q based on this information and in accordance with the operation amount input to the control lever 41. The target flow rate Q of the hydraulic oil supplied to the boom cylinder 20 can be adjusted by the valve opening A (opening area) of the boom control valve 12, as shown in FIG. 7. That is, the opening area of ​​the boom control valve 12 for supplying hydraulic oil to the boom cylinder 20 is adjusted by the command current (command signal) input to the first proportional valve 121 and the second proportional valve 122, so that the target flow rate Q can be adjusted with high precision. On the other hand, if no operation is input to the control lever 41 in step S1, the control unit 50 ends the flow of FIG. 4.

[0058] In step S2, the target flow rate Q T When is calculated, the determination unit 502 determines whether the operation input to the operation lever 41 has switched from ON to OFF (step S3). In other words, the determination unit 502 determines whether the operation lever 41 has been operated from a lowering region where the boom 4 is rotated in the boom-down direction to a neutral region where the boom 4 is stopped from being raised or lowered. At this time, the determination unit 502 can determine the change in operation in accordance with a command signal input from the operation command unit 42 (FIG. 2). If the operation lever 41 is an electric lever, an operation angle signal output from the operation command unit 42 is input to the control unit 50. If the boom operation unit 40 is a hydraulic lever, the secondary pressure of the operation command unit 42, which functions as a remote control valve, is detected by a sensor (not shown) and input to the control unit 50.

[0059] In step S3, if the control lever is turned OFF (YES in step S3), the determination unit 502 determines that the operator has performed a neutral operation (step S4). As a result, the control unit 50 imparts a transient characteristic to the command current input to the first proportional valve 121 to return the spool of the boom control valve 12 to the neutral position (step S5). With reference to FIG. 8, the control unit 50 sets the command current I at the time when it is determined that the neutral operation has been performed (neutral determination) as a transient characteristic initial command current I0, and sets the command current input to the first proportional valve 121 to be smaller than the initial command current planned value (broken line in FIG. 8) starting from this command current I0. In other words, the control unit 50 gradually changes the command current input to the first proportional valve 121 compared to the amount of operation input to the control lever 41. As a result, in step S6, the command current is input to the first proportional valve 121, and the opening of the boom control valve 12 gradually closes.

[0060] FIG. 9 is a graph showing the relationship between the speed (actuator speed) of the boom cylinder 20 and the time constant when the hydraulic excavator 100 is determined to be in a neutral position. In this embodiment, when imparting a transient characteristic to the command current in step S5, the control unit 50 may obtain the drive speed of the boom cylinder 20 when the neutral position is determined from the detection result of the speed detection unit 25, and set the command current to be input to the first proportional valve 121 by multiplying the command current by a preset time constant according to the drive speed (actuator speed) of the boom cylinder 20, as shown in FIG. 9. In this embodiment, as shown in FIG. 9, the greater the drive speed detected by the speed detection unit 25 when the operating lever 41 is subjected to a stop operation, the larger the time constant is set, i.e., the smaller the command current I in FIG. 8 is set. This means that, in the relationship between the lever operation amount and the target flow rate Q in FIG. 6, a delay is imparted to the command signal to the first proportional valve 121 so that the flow rate of hydraulic oil corresponding to the operation amount of the stop operation is smaller than that shown in the graph (relationship) of FIG. 6 (so as to reduce the amount of hydraulic oil discharged from the boom cylinder 20).

[0061] When a neutral operation is input to the control lever 41, a command signal is input to the first proportional valve 121 (step S6 in FIG. 5 ), as described above, and the flow in FIG. 5 is repeated. As described above, in this embodiment, when the operator operates the control lever 41 to the neutral region and a transient characteristic (first-order lag) is applied to the command current I to the first proportional valve 121, the pilot pressure (secondary pressure) is directly adjusted and the opening of the boom control valve 12 gradually closes with high precision. This brakes the retraction operation of the boom cylinder 20, making it possible to stop the boom cylinder 20, i.e., the boom 4, in a short time without shock. In particular, in this embodiment, because the secondary pressure is directly controlled by the first proportional valve 121, stable adjustment of the opening area is possible without being affected by the spool volume in the boom control valve 12.

[0062] Furthermore, in this embodiment, as shown in FIG. 4 , when the stroke amount of the spool of boom control valve 12 changes toward zero in accordance with the neutral operation, a region is set in which the meter-in opening closes first and only the meter-out opening opens. In this region, the supply of hydraulic oil from hydraulic pump 10 to boom control valve 12 is blocked because the meter-in opening is closed, thereby preventing shocks from occurring due to the hydraulic oil being forced into boom cylinder 20. Note that the timing at which control unit 50 imparts a transient characteristic to the command signal may start before the stroke amount of the spool reaches this region. By imparting the transient characteristic at least in this region, stable and gentle braking can be applied to boom cylinder 20.

[0063] In step S3, if the operating lever 41 has not been operated from ON to OFF (NO in step S3), the determination unit 502 of the control unit 50 determines that a neutral operation has not been performed, and inputs a command signal to the first proportional valve 121 so that the opening degree A (opening area) corresponds to the amount of operation input to the operating lever 41 based on the relationship in Figures 6 and 7, thereby setting the amount of movement of the spool of the boom control valve 12 (step S8). In this case, the flow in Figure 5 is also repeated. The cycle of control in the flow in Figure 5 executed by the control unit 50 can be set arbitrarily depending on the characteristics of the hydraulic circuit of the control device 100A.

[0064] 10 and 11 are graphs showing changes over time in the lever operation amount of the operating lever 41, the cylinder pressure in the head chamber 20H of the boom cylinder 20, the meter-out opening of the boom control valve 12, and the cylinder speed of the boom cylinder 20 in a hydraulic excavator 100 equipped with the control device 100A according to this embodiment. Fig. 10 shows the graphs for the case where the operating lever 41 is gently returned to the neutral position (gentle lever braking), and Fig. 11 shows the graphs for the case where the operating lever 41 is suddenly returned to the neutral position (sudden lever braking).

[0065] As shown in FIG. 10, when the operating lever 41 is gently returned from the lying-down region to the neutral region, for example, there is no significant difference in the graphs between the case with the control according to this embodiment and the case without the control. This is because the operating lever 41 is gently operated to the neutral region, so the meter-out opening gradually closes and the cylinder speed of the boom cylinder 20 gradually changes toward zero without the aforementioned transient characteristics having a significant effect. In the case of such a gentle neutral operation, a large shock is unlikely to occur in the boom cylinder 20. Therefore, as shown in FIG. 9, when the speed of the boom cylinder 20 is slow due to a gentle neutral operation, the boom cylinder 20 can be decelerated quickly by setting a small time constant.

[0066] On the other hand, referring to Figure 11, if the control according to this embodiment is not executed when the operator suddenly returns the operating lever 41 from the lowering region to the neutral region, the meter-out opening suddenly closes, and the brakes are applied so that the cylinder speed also suddenly becomes zero. At this time, the hydraulic oil that is momentarily unable to go anywhere causes the pressure in the boom cylinder 20 to fluctuate greatly, causing a shock. In this case, the relief valve 35 included in the aforementioned protection circuits 31 and 32 discharges the hydraulic oil from the boom cylinder 20 to the tank T, but it takes a certain amount of time for the shock (vibration) to subside.

[0067] In contrast, when the control according to this embodiment is executed, the meter-out opening gradually closes as shown in FIG. 11 due to the transient characteristics of the command current input to the first proportional valve 121, so that a gentle brake can be applied so that the cylinder speed approaches zero while reducing the fluctuation of the cylinder pressure.

[0068] The above-described brake function is particularly effective when the operator suddenly performs a neutral operation while the boom is being lowered, i.e., when an operation to stop the boom lowering operation is performed. In such an operation, with a conventional control device, if a sudden brake operation is performed during the boom lowering operation, the boom 4 continues to lower under its own weight, and hydraulic oil discharged from the boom cylinder 20 attempts to flow into the control valve corresponding to the boom control valve 12. However, in this control valve, hydraulic oil cannot be discharged from the meter-out opening due to the brake operation, resulting in high cylinder pressure, which causes excessive negative thrust and a large shock. On the other hand, when the control according to this embodiment is executed, it is possible to gently control the movement of the spool of the boom control valve 12 in response to an electrical command signal input to the first proportional valve 121. Furthermore, hydraulic oil is gently discharged to the tank through the boom control valve 12 while the meter-in opening of the boom control valve 12 is closed and the meter-out opening is open. This effectively suppresses the occurrence of the above-described shock. In other words, the control according to this embodiment does not necessarily have to be executed during a neutral operation for a boom-raising operation that rotates the boom 4 in the raising direction. The reduction of shock during the boom-raising operation can also be mitigated by adjusting the discharge amount and discharge pressure of the hydraulic oil discharged from the hydraulic pump 10.

[0069] As described above, in this embodiment, when the control lever 41 receives an operation to raise or lower the boom 4, the control unit 50 inputs the command signals to the first proportional valve 121 and the second proportional valve 122 so that hydraulic oil is supplied to or discharged from the boom cylinder 20 based on the relationship between the preset operation amount and the target flow rate Q to the boom cylinder 20 ( FIG. 6 ). On the other hand, when the control lever 41 receives a stop operation to stop the boom 4 while a predetermined control condition is satisfied, the control unit 50 inputs command signals to the first proportional valve 121 and the second proportional valve 122 so that the target flow rate Q relative to the operation amount of the stop operation becomes smaller than the relationship described above, i.e., so that the meter-out opening closes at a timing delayed from the relationship between the operation and the opening. Furthermore, the boom control valve 12 is set so that the meter-in opening that supplies hydraulic oil to the boom cylinder 20 closes earlier than the meter-out opening that receives hydraulic oil from the boom cylinder 20 due to movement of the spool associated with the stop operation. The control condition applies, for example, when a switch (not shown) for control according to this embodiment is turned on.

[0070] In a configuration in which the spool of the boom control valve 12 is moved by inputting such command signals to the first proportional valve 121 and the second proportional valve 122, it is possible to arbitrarily change the dynamic characteristics of the spool in response to the amount of lever operation received by the control lever 41, and to maintain high resolution for adjusting the stroke amount of the spool. In particular, when the control lever 41 is operated to stop, the control unit 50 can input a delay in the command signal to the first proportional valve 121, thereby stopping the boom cylinder 20 while gently braking the boom cylinder 20. As a result, the stop control of the boom 4 can be performed stably and smoothly. Furthermore, since the boom control valve 12 has a region in which the meter-in opening closes first and only the meter-out opening is open in response to a stop operation, application of pressure through the meter-in opening of the boom control valve 12 during the stopping operation is suppressed, and shock caused by the pressure can be prevented.

[0071] In particular, in this embodiment, when the operating lever 41 receives the stop operation, the control unit 50 inputs a command signal to the first proportional valve 121 so that, with the meter-in opening of the boom control valve 12 closed and the meter-out opening open, the meter-out opening is closed at a timing that is delayed from the relationship between the operation and the opening degree.

[0072] According to this configuration, by delaying the command signal input by the control unit 50 to the first proportional valve 121 in accordance with the region where the meter-in opening of the boom control valve 12 is closed, it is possible to stop the boom cylinder 20 while applying a gentle brake to the boom cylinder 20 in a stable manner.

[0073] Furthermore, in this embodiment, the control unit 50 inputs a command signal to the second proportional valve 122 so that the greater the drive speed detected by the speed detection unit 25 when the operating lever 41 receives the stop operation, the later the timing at which the meter-out opening closes than in the relationship between the operation and the opening degree shown in Figures 6 and 7.

[0074] With this configuration, it is possible to reliably suppress the occurrence of shock by applying the brake more gently when the drive speed of the boom cylinder 20 is high and the flow rate of hydraulic oil discharged from the boom cylinder 20 is large. Furthermore, when the drive speed of the boom cylinder 20 is low, the flow rate of hydraulic oil discharged is small and shock is less likely to occur, so the boom cylinder 20 can be stopped quickly.

[0075] Furthermore, in this embodiment, the control device 100A has protection circuits 31 and 32, which include a check valve 36. Therefore, even if the boom cylinder 20 becomes under negative pressure, hydraulic oil can be supplied to the boom cylinder 20 from the tank T through the check valve 36. In particular, when the neutral operation is performed during the boom lowering operation, the meter-in opening of the boom control valve 12 closes first, which makes it easy for the rod chamber 20R of the boom cylinder 20 to become under negative pressure. Even in such a case, by supplying hydraulic oil to the rod chamber 20R using the check valve 36, pressure fluctuations in the boom cylinder 20 can be suppressed, further suppressing the occurrence of shock during braking.

[0076] Furthermore, in this embodiment, the control device 100A has an arm control valve 11 (auxiliary valve mechanism). The arm control valve 11 controls the flow rate of hydraulic oil supplied to and discharged from an arm cylinder 8 (another hydraulic cylinder) different from the boom cylinder 20. The arm control valve 11 is capable of supplying hydraulic oil to the boom cylinder 20 through the meter-in opening of the boom control valve 12.

[0077] During combined operation in which the boom 4 (boom cylinders 7, 20) and the arm 5 (arm cylinder 8) are operated simultaneously, when the boom 4 is neutralized, the operating pressure of the arm control valve 11 acts as a pushing pressure on the meter-in opening side of the boom control valve 12, which may increase the risk of shock and vibration in the boom cylinder 20. However, in this embodiment, as described above, the meter-in opening of the boom control valve 12 closes first, preventing the hydraulic oil supplied from the arm control valve 11 from being supplied to the boom cylinder 20, thereby preventing the occurrence of shock and vibration as described above. Furthermore, in the region where the meter-in opening is closed and the meter-out opening is open, a delay characteristic such as a first-order delay is imparted to the command signal input to the first proportional valve 121, making it possible to apply the brakes gently without being affected by the pushing pressure from the meter-in opening.

[0078] Furthermore, in this embodiment, when the operating lever 41 is operated from the lowering region to the neutral region as the stop operation, the control unit 50 imparts a transient characteristic to the command current so that the target flow rate Q relative to the operation amount of the stop operation becomes smaller than the relationship in Fig. 6, and then inputs the command current (command signal) to the first proportional valve 121. Therefore, even during a neutral operation during boom lowering, where shock is likely to occur when stopping due to the weight of the boom 4, the boom lowering operation can be stopped gently.

[0079] Note that, when the operating lever 41 is operated from the lowering region to the neutral region as the stopping operation, and then the operating lever 41 is further operated from the neutral region to the standing region, it is desirable that the control unit 50 inputs command currents to the first proportional valve 121 and the second proportional valve 122 and supplies or discharges hydraulic oil to or from the boom cylinder 20 based on the preset relationship in Fig. 6, that is, so that the boom cylinder 20 operates at a speed according to the amount of operation received by the operating lever 41. In this case, the meter-out opening closes quickly in response to the boom lowering operation, and the meter-in opening and the meter-out opening open smoothly in response to the boom raising operation.

[0080] With this configuration, even if a neutral operation has been performed, when an operation in the opposite direction is input to the operating lever 41, in other words, when an operation for a boom-raising operation is input following the stopping of a boom-lowering operation, a gradual braking operation can be avoided and the boom cylinder 20 can be quickly driven in the opposite direction, thereby preventing excessive braking action.

[0081] Furthermore, in this embodiment, by delaying the command signal input by the control unit 50 to the pair of first proportional valves 121 (proportional valves), it is possible to stop the hydraulic cylinder 20 while gently braking the boom cylinder 20.

[0082] The control device 100A according to the present invention and the hydraulic excavator 100 equipped with the same have been described above, but the present invention is not limited to this and can take on modified embodiments such as those described below.

[0083] (1) In the above embodiment, the control device 100A includes a pair of first proportional valves 121 and second proportional valves 122, and the boom control valve 12 includes a pair of pilot ports 12A and 12B. However, the present invention is not limited to this. The control device 100A may include a proportional electromagnetic directional flow control valve having a pair of solenoids instead of the boom control valve 12. In this case, the pair of solenoids constitute the valve drive unit of the present invention. The pair of solenoids receive command signals (command currents) from the control unit 50 and move the spool in response to the command signals. Even in this configuration, when a neutral operation is received, the control unit 50 can delay the command signals input to the pair of solenoids to stop the boom cylinder 20 while gently braking the boom cylinder 20. As a result, shocks can be prevented from occurring when the boom 4 is stopped.

[0084] (2) In the above embodiment, the control device 100A may further include a detection unit that detects the stroke amount of the spool of the boom cylinder 20. In this case, the detection result of the detection unit may be fed back to correct and control the command current input to the first proportional valve 121 and the second proportional valve 122.

[0085] (3) Furthermore, in the above embodiment, the control valve directly connected to the boom cylinder 20 is one boom control valve 12. However, in order to increase the drive speed of the boom cylinder 20, two control valves may be provided and the hydraulic oil discharged from the two control valves may be joined to drive the boom cylinder 20. In this case, it is desirable to apply the control as described in the above embodiment to one of the two control valves in order to smoothly perform the boom-raising operation and the boom-lowering operation.

[0086] (4) In the above embodiment, the arm control valve 11 is disposed between the boom control valve 12 and the hydraulic pump 10. However, such a combined control valve configuration may be adopted in other embodiments. As an example, instead of the arm control valve 11, a control valve that controls the supply of hydraulic oil to the swing motor of the upper swing body 2 may be provided.

[0087] (5) In the above embodiment, the boom control valve 12 constitutes the supply-side valve mechanism and the recovery-side valve mechanism of the present invention. However, the present invention is not limited to this. As an example, two control valves may be provided, with one of the two control valves constituting the supply-side valve mechanism and the other constituting the recovery-side valve mechanism. That is, one of the control valves has a supply port (meter-in opening) for hydraulic oil from the hydraulic pump 10 to the boom cylinder 20, and the other control valve has a recovery port (meter-out opening) for hydraulic oil from the boom cylinder 20. Each control valve has a movable spool, and by controlling the movement of each spool, the boom cylinder 20 can be stopped while gently braking. As a result, the boom 4 can be stopped stably and smoothly. Furthermore, the two control valves have a region in which the supply port closes first and only the recovery port opens during a stopping operation. This prevents pressure from being applied through the supply port of one of the control valves during a stopping operation, thereby preventing shock caused by the pressure. As described above, the supply-side valve mechanism and the recovery-side valve mechanism of the present invention each have at least one spool, and may have multiple spools. Furthermore, each valve mechanism is not limited to having a spool, and may be a valve having another mechanical structure.

[0088] (6) Furthermore, the tip attachment of the work attachment 3 is not limited to a bucket, but may be other tip attachments such as a grapple, crusher, breaker, or fork. Furthermore, the construction machine on which the control device of the present invention is installed is not limited to the hydraulic excavator, but may be other construction machines. Furthermore, the movable members and actuators controlled by the control device of the present invention are not limited to a boom and boom cylinder, but may be an arm and arm cylinder, an upper rotating body 2, a rotating motor, or the like.

[0089] (7) In the previous embodiment, the machine body includes a lower running body 1, but the machine body is not limited to being capable of running like the lower running body 1, and may be a base installed in a specific location and supporting the upper rotating body 2. [Explanation of symbols]

[0090] 1 Undercarriage (airframe) 100 Hydraulic Excavator 100A control device 2 Upper rotating body (aircraft) 3 Work attachments 4 Boom (movable part) 5 Arm 6 buckets 7 Boom cylinder 8 Arm Cylinder 9 Bucket cylinder 10 Hydraulic pump 11 Arm control valve (auxiliary valve mechanism) 12 Boom control valve (supply side valve mechanism and return side valve mechanism) 121 First proportional valve (valve drive unit, proportional valve) 122 Second proportional valve (valve drive unit, proportional valve) 12A, 12B pilot ports 20 Boom cylinder 20H head room 20R Rod Room 21 Cylinder body 22 Cylinder rod 23 Piston section 25 Speed ​​detection unit 31, 32 Protection circuit 35 Relief valve 36 Check valve 40 Boom control unit 41 Operating lever 42 Operation command section 50 control section 501 Arithmetic unit 502 Judgment section 503 Storage section

Claims

1. A control device for a construction machine having a movable member, A hydraulic pump, an operating unit that receives an operation for moving the movable member; an actuator that receives hydraulic oil from the hydraulic pump and moves the movable member; a supply-side valve mechanism including a supply port for hydraulic oil from the hydraulic pump to the actuator, the supply port being capable of changing an opening degree of the supply port; a recovery-side valve mechanism including a recovery port for hydraulic oil from the actuator, the recovery port being capable of changing an opening degree of the recovery port; a valve driving unit capable of changing the opening degree of the supply port and the recovery port in response to an input command signal; a control unit that inputs the command signal to the valve drive unit so that the supply port and the recovery port are opened at an opening degree corresponding to the operation, and when the operation is a stopping operation for stopping the movable member, inputs the command signal to the valve drive unit so that the recovery port is closed at a timing delayed from the relationship between the operation and the opening degree; Equipped with The movable member is a boom supported on the aircraft body so as to be able to be raised and lowered, A control device for a construction machine, wherein the supply side valve mechanism and the recovery side valve mechanism are configured such that when a stop operation indicating the cessation of the boom's lowering operation is received, the supply port closes before the recovery port in response to the stop operation.

2. 2. The control device for a construction machine according to claim 1, wherein the control unit inputs the command signal to the valve drive unit so that, when the supply port is closed and the recovery port is open in response to the stop operation, the recovery port is closed at a timing that is delayed relative to the relationship between the operation and the opening degree.

3. 3. The construction machine control device according to claim 1, further comprising a check valve arranged between the supply-side valve mechanism and the recovery-side valve mechanism and the actuator, which allows hydraulic oil to be supplied from a tank to the actuator when the actuator becomes negative pressure.

4. 4. A control device for a construction machine according to claim 1, further comprising an auxiliary valve mechanism that is arranged between the supply side valve mechanism and the recovery side valve mechanism and the hydraulic pump, and that opens to adjust the flow rate of hydraulic oil supplied to an actuator other than the actuator, and that is capable of supplying hydraulic oil to the actuator through the supply port.

5. the actuator is a hydraulic cylinder having a cylinder body and a cylinder rod that divides the cylinder body into a head chamber and a rod chamber and is movable relative to the cylinder body, When the hydraulic cylinder receives hydraulic oil into the head chamber through the supply-side valve mechanism and discharges hydraulic oil from the rod chamber, the cylinder rod extends relative to the cylinder body so as to rotate the boom in an upright direction, and when the hydraulic cylinder receives hydraulic oil into the rod chamber through the supply-side valve mechanism and discharges hydraulic oil from the head chamber, the cylinder rod contracts relative to the cylinder body so as to rotate the boom in a lowering direction, the operation unit can be operated to a raising region for raising the boom, a lowering region for lowering the boom, and a neutral region for stopping the raising and lowering of the boom, 5. A control device for a construction machine according to claim 1, wherein when the operating unit is operated from the lowering region to the neutral region as the stopping operation, the control unit inputs the command signal to the valve drive unit so that the recovery port closes at a timing that is delayed relative to the relationship between the operation and the opening degree.

6. 6. A control device for a construction machine as described in claim 5, wherein when the operating unit is operated from the lying-down region to the neutral region as the stopping operation and then further operated from the neutral region to the standing region, the control unit inputs the command signal to the valve drive unit so that the recovery port closes and then the supply port and the recovery port open based on the relationship.

7. a control valve that functions as the supply-side valve mechanism and the recovery-side valve mechanism; the control valve has at least one spool that moves to change the opening degree of the supply port and the recovery port; the valve driving unit moves the at least one spool by an amount corresponding to the input command signal so as to change the opening degrees of the supply port and the recovery port; 7. The control device for a construction machine according to claim 1, wherein the control valve is configured so that the supply port closes before the recovery port due to movement of the at least one spool.

8. The valve drive unit is a pair of pilot ports provided in the control valve for receiving pilot pressure for moving the spool; a pair of proportional valves that receive the command signal from the control unit and open in response to the command signal to adjust the pilot pressure acting on the pair of pilot ports; The control device for a construction machine according to claim 7, further comprising:

9. The control device for a construction machine according to claim 7, wherein the valve drive unit has a pair of solenoids that receive the command signal from the control unit and move the spool in response to the command signal.

10. The aircraft and a movable member supported on the airframe; A construction machine control device according to any one of claims 1 to 9; Construction machinery equipped with:

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