Work Machine

Abstract

The purpose of the present invention is to provide a work machine in which, during a combined operation for simultaneously driving a turning motor and another actuator, the speed control for the actuator and the torque control for the turning motor can be performed with a simple configuration. To do so, a controller: calculates a target pump flow rate on the basis of a target actuator flow rate and a target turning flow rate; calculates a target meter-in opening area of an actuator direction control valve on the basis of the target actuator flow rate, a pump pressure, and an actuator meter-in pressure; calculates a target torque for the turning motor on the basis of an input amount of an operation device and an output value of a posture sensor; calculates a target turning meter-out pressure on the basis of the target torque and a turning meter-in pressure; and calculates a target meter-out opening area of the turning direction control valve on the basis of the target turning meter-out pressure and a turning meter-out pressure.

Description

[Technical field]

[0001] The present invention relates to a work machine such as a hydraulic excavator. [Background technology]

[0002] Generally, various hydraulic actuators are provided in work machines such as hydraulic excavators, and a widely known control circuit for controlling the supply and discharge of hydraulic oil to and from such hydraulic actuators is configured to use a single spool valve for direction switching control, which switches the direction in which hydraulic oil is supplied to and discharged from the hydraulic actuator, meter-in opening control, which controls the supply flow rate from the hydraulic pump to the hydraulic actuator, and meter-out opening control, which controls the discharge flow rate from the hydraulic actuator to a hydraulic oil tank.

[0003] In this manner, when the meter-in opening control and the meter-out opening control are performed by a single spool valve, the relationship between the opening area on the meter-in side and the opening area on the meter-out side relative to the movement position of the spool valve is uniquely determined.

[0004] Therefore, it is not possible to change the relationship between the opening area on the meter-in side and the opening area on the meter-out side depending on various types of work, such as a single operation in which one hydraulic actuator is driven alone, a combined operation in which multiple hydraulic actuators are driven simultaneously, or light work or heavy work. Therefore, when controlling the supply flow rate to the actuator using meter-in opening control, or when controlling the discharge flow rate from the actuator using meter-out opening control, one opening control may interfere with the other opening control, which may reduce operability.

[0005] Therefore, a control circuit has been known in the past that controls the oil supply and discharge to a hydraulic actuator using a bridge circuit formed using four metering valves: head side and rod side supply valves (head end and rod end supply valves) that control the supply flow rate from the hydraulic pump to the head side oil chamber and rod side oil chamber of the hydraulic cylinder, respectively, and head side and rod side discharge valves (head end and rod end drain valves) that control the discharge flow rate from the head side oil chamber and rod side oil chamber to the oil tank, respectively (for example, Patent Document 1).

[0006] In the control circuit of Patent Document 1, the four metering valves operate individually based on commands from a controller, making it possible to easily change the relationship between the meter-in opening and the meter-out opening depending on the work content, etc.

[0007] Also known is a control circuit in which an auxiliary valve with a variable resistance function is disposed upstream of a directional control valve that performs the above-mentioned directional control, meter-in opening control, and meter-out opening control with a single spool valve, and the auxiliary valve supplements the supply of pressurized oil to the directional control valve depending on the work content, such as a single operation or a combined operation, etc. (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5214450 [Patent Document 2] Patent No. 3511425 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the control circuit of Patent Document 1, in order to control the oil supply and discharge to the hydraulic actuator using four metering valves, in addition to the four spools (or poppets) that make up each of the four metering valves, four actuators (solenoids in Patent Document 1) are required to drive each spool, which poses the problem of increased costs due to the complexity of the circuit and the increased number of parts.

[0010] On the other hand, in the control circuit of Patent Document 2, although the pressure oil distribution and priority to each hydraulic actuator during a combined operation can be controlled by an auxiliary valve, the meter-in opening control and the meter-in opening control for the hydraulic actuators are not performed by a single directional control valve. Out Since aperture control is performed as in the past, the problem of one aperture control interfering with the other aperture control remains unresolved.

[0011] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a work machine that is capable of performing actuator speed control and swing motor torque control with a simple configuration during combined operation in which the actuator and swing motor are driven simultaneously. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention provides a work machine including a traveling body, a rotating body rotatably attached on the traveling body, a working device attached to the rotating body, a hydraulic oil tank, a variable displacement hydraulic pump that draws in and discharges hydraulic oil from the hydraulic oil tank, a regulator that controls the capacity of the hydraulic pump, an actuator that drives the working device, a swing motor that drives the rotating body, an actuator directional control valve that controls the flow of pressure oil supplied from the hydraulic pump to the actuator, a swing direction control valve that controls the flow of pressure oil supplied from the hydraulic pump to the swing motor, an operating device that instructs operations of the actuator and the swing motor, and a controller that controls the regulator, the actuator directional control valve, and the swing direction control valve in accordance with an input amount of the operating device, the work machine including a first pressure sensor that detects pump pressure, which is the discharge pressure of the hydraulic pump, a second pressure sensor that detects actuator meter-in pressure, which is the pressure on the meter-in side of the actuator, swing meter-in pressure, which is the pressure on the meter-in side of the swing motor, and a third pressure sensor that detects a swing meter-out pressure which is the pressure on the meter-out side of the swing motor, and a posture sensor that detects the posture of the swing body and the working device, wherein the actuator directional control valve and the swing direction control valve each have a meter-in opening and a meter-out opening formed in the same valve body, the actuator directional control valve is formed so that the meter-in opening becomes smaller than the meter-out opening with respect to valve displacement, and the swing direction control valve is formed so that the meter-out opening becomes smaller than the meter-in opening with respect to valve displacement, and the controller calculates an actuator target flow rate which is a target value of the flow rate of pressure oil supplied from the hydraulic pump to the actuator based on an input amount of the operating device, calculates a swing target flow rate which is a target value of the flow rate of pressure oil supplied from the hydraulic pump to the swing motor based on the input amount of the operating device, calculates a pump target flow rate which is a target value of the discharge flow rate of the hydraulic pump based on the actuator target flow rate and the swing target flow rate, and calculates a pump target flow rate which is a target value of the discharge flow rate of the hydraulic pump based on the actuator target flow rate, the pump pressure, and the actuator meter-in pressure,A target meter-in opening area, which is a target value of a meter-in opening area of ​​the actuator directional control valve, is calculated, a target torque, which is a target value of an input torque to the swing motor, is calculated based on the input amount of the operating device and the output value of the attitude sensor, a target value of the swing meter-out pressure is calculated based on the target torque and the swing meter-in pressure, value A target meter-out pressure is calculated based on the target swirl meter-out pressure and the swirl meter-out pressure, a target meter-out opening area which is a target value of the meter-out opening area of ​​the swirl direction control valve is calculated, the regulator is controlled in accordance with the target pump flow rate, the actuator directional control valve is controlled in accordance with the target meter-in opening area, and the swirl direction control valve is controlled in accordance with the target meter-out opening area.

[0013] According to the present invention configured as described above, during combined operation in which the swing motor and other actuators are driven simultaneously, the meter-in opening is adjusted according to the front-rear differential pressure of the boom directional control valve to supply a target flow rate to the boom cylinder, thereby allowing the boom to move at a target speed. Also, by adjusting the meter-out opening of the swing directional control valve to input a target torque to the swing motor, overshooting due to the inertia of the swing body can be prevented. Furthermore, the pump target flow rate of the hydraulic pump is the sum of the boom target flow rate and the swing target flow rate, and a flow rate obtained by subtracting the supply flow rate to the boom cylinder from the discharge flow rate of the hydraulic pump is supplied to the swing motor, allowing the swing body to move at a target speed. As a result, with a simple configuration using a directional control valve that performs meter-in opening control and meter-out opening control with the same valve body, it is possible to perform actuator speed control and swing motor torque control during combined operation in which the swing motor and other actuators are driven simultaneously. Effect of the Invention

[0014] According to the work machine of the present invention, during combined operation in which the swing motor and other actuators are driven simultaneously, it is possible to perform speed control of the actuators and torque control of the swing motor with a simple configuration. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a side view of a hydraulic excavator according to an embodiment of the present invention. [Figure 2A] FIG. 2 is a circuit diagram (1 / 2) of a hydraulic drive system mounted on the hydraulic excavator shown in FIG. 1. [Figure 2B] FIG. 2 is a circuit diagram (2 / 2) of a hydraulic drive system mounted on the hydraulic excavator shown in FIG. 1. [Diagram 3] FIG. 2B is a diagram showing the opening characteristics of the directional control valve (other than the swing directional control valve) shown in FIG. 2A. [Figure 4] FIG. 2B is a diagram showing the opening characteristics of the swing direction control valve shown in FIG. 2A. [Diagram 5] FIG. 2C is a functional block diagram of the controller shown in FIG. 2B. [Figure 6] 2B is a diagram showing the opening characteristics of the bleed-off valve shown in FIG. 2A relative to the operating lever input amount. FIG. [Figure 7] 2C is a flowchart showing a process related to pump flow rate control by a controller shown in FIG. 2B. [Figure 8] 2C is a flowchart showing processing related to opening control of a boom direction control valve by a controller shown in FIG. 2B. [Figure 9] 2C is a flowchart showing a process related to opening control of the swing direction control valve of the controller shown in FIG. 2B. [Figure 10] 2C is a flowchart showing a process related to opening control of the bleed-off valve by the controller shown in FIG. 2B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a hydraulic excavator will be described as an example of a work machine according to an embodiment of the present invention with reference to the drawings. In each drawing, the same reference numerals are used to designate the same members, and duplicated descriptions will be omitted as appropriate.

[0017] Fig. 1 is a side view of a hydraulic excavator according to this embodiment. As shown in Fig. 1, a hydraulic excavator 901 includes a traveling body 201, a rotating body 202 that is rotatably disposed on the traveling body 201 and constitutes a vehicle body, and a working device 203 that is attached to the rotating body 202 so as to be rotatable in the vertical direction and performs work such as excavating earth and sand. The rotating body 202 is driven by a swing motor 211.

[0018] The working device 203 includes a boom 204 attached to the revolving body 202 so as to be rotatable in the vertical direction, an arm 205 attached to the tip of the boom 204 so as to be rotatable in the vertical direction, a bucket 206 attached to the tip of the arm 205 so as to be rotatable in the vertical direction, a boom cylinder 204a which is an actuator for driving the boom 204, an arm cylinder 205a which is an actuator for driving the arm 205, and a bucket cylinder 206a which is an actuator for driving the bucket 206. The working device 203 is provided with inertial measurement units 212, 213, and 214 which detect the attitude and operation state of the boom 204, the arm 205, and the bucket 206. The revolving body 202 is provided with inertial measurement units 215 and 216 which detect the attitude and rotation speed of the revolving body 202. That is, the inertial measurement units 212 to 216 in this embodiment constitute attitude sensors which detect the attitudes of the revolving body 202 and the working device 203.

[0019] A cab 207 is provided at the front position on the rotating body 202, and a counterweight 209 is attached at the rear position to ensure the weight balance of the vehicle body. A machine room 208 is provided between the cab 207 and the counterweight 209. The machine room 208 accommodates an engine (not shown), a control valve 210, a swing motor 211, hydraulic pumps 1 to 3 (shown in FIG. 2A), etc. The control valve 210 controls the flow of hydraulic oil from the hydraulic pump to each actuator.

[0020] 2A and 2B are circuit diagrams of a hydraulic drive system mounted on a hydraulic excavator 901. FIG.

[0021] (composition) The hydraulic drive system 902 includes three main hydraulic pumps (for example, a first hydraulic pump 1, a second hydraulic pump 2, and a third hydraulic pump 3, which are variable displacement hydraulic pumps), a pilot pump 91, and a hydraulic oil tank 5 that supplies oil to the hydraulic pumps 1 to 3 and the pilot pump 91. The hydraulic pumps 1 to 3 and the pilot pump 91 are driven by an engine (not shown).

[0022] The tilt angle of the first hydraulic pump 1 is controlled by a regulator attached to the first hydraulic pump 1. The regulator of the first hydraulic pump 1 has a flow control command pressure port 1a, and is driven by a command pressure acting on the flow control command pressure port 1a. The tilt angle of the second hydraulic pump 2 is controlled by a regulator attached to the second hydraulic pump 2. The regulator of the second hydraulic pump 2 has a flow control command pressure port 2a, and is driven by a command pressure acting on the flow control command pressure port 2a. The tilt angle of the third hydraulic pump 3 is controlled by a regulator attached to the third hydraulic pump 3. The regulator of the third hydraulic pump 3 has a flow control command pressure port 3a, and is driven by a command pressure acting on the flow control command pressure port 3a.

[0023] A right travel direction control valve 6, a bucket direction control valve 7, a second arm direction control valve 8, and a first boom direction control valve 9 are connected in parallel to a pump line 40 of the first hydraulic pump 1 via flow paths 41, 42, flow paths 43, 44, flow paths 45, 46, and flow paths 47, 48, respectively. In the flow paths 41, 42, flow paths 43, 44, flow paths 45, 46, and flow paths 47, 48, check valves 21 to 24 are arranged to prevent backflow of pressure oil to the pump line 40. The right travel direction control valve 6 controls the flow of pressure oil supplied from the first hydraulic pump 1 to a right travel motor (not shown) of a pair of travel motors that drive the travel body 201. The bucket direction control valve 7 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the bucket cylinder 206a. The second arm direction control valve 8 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the arm cylinder 205a. The first boom directional control valve 9 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the boom cylinder 204a. The pump line 40 is connected to the hydraulic oil tank 5 via a main relief valve 18 to protect the circuit from an excessive pressure rise. The pump line 40 is connected to the hydraulic oil tank 5 via a bleed-off valve 35 to discharge excess discharge oil from the hydraulic pump 1.

[0024] The second boom direction control valve 10, the first arm direction control valve 11, the first attachment direction control valve 12, and the left traveling direction control valve 13 are connected in parallel to the pump line 50 of the second hydraulic pump 2 via flow paths 51, 52, flow paths 53, 54, flow paths 55, 56, and flow paths 57, 58, respectively. In order to prevent backflow of pressure oil to the pump line 50, check valves 25 to 28 are arranged in the flow paths 51, 52, flow paths 53, 54, flow paths 55, 56, and flow paths 57, 58, respectively. The second boom direction control valve 10 controls the flow of pressure oil supplied from the second hydraulic pump 2 to the boom cylinder 204a. The first arm direction control valve 11 controls the flow of pressure oil supplied from the second hydraulic pump 2 to the arm cylinder 205a. The first attachment directional control valve 12 controls the flow of pressure oil supplied from the second hydraulic pump 2 to a first actuator (not shown) that drives a first special attachment such as a small-cutting machine provided in place of the bucket 206. The left-traveling directional control valve 13 controls the flow of pressure oil supplied from the second hydraulic pump 2 to a left-traveling motor (not shown) of a pair of travelling motors that drive the travelling body 201. The pump line 50 is connected to the hydraulic oil tank 5 via a main relief valve 19 to protect the circuit from an excessive pressure rise. The pump line 50 is connected to the hydraulic oil tank 5 via a bleed-off valve 36 to discharge excess discharge oil from the hydraulic pump 2. The pump line 50 is connected to the pump line 40 via a junction valve 17 to merge the discharge oil from the first hydraulic pump 1. A check valve 32 is provided at a portion of the pump line 50 that connects the flow path 55 and the flow path 57. The check valve 32 prevents the pressure oil that flows from the first hydraulic pump 1 through the junction valve 17 to join the pump line 50 from flowing into the directional control valves 10 to 12 other than the traveling left directional control valve 13 .

[0025] The swing direction control valve 14, the third boom direction control valve 15, and the second attachment direction control valve 16 are connected in parallel to the pump line 60 of the third hydraulic pump 3 via flow paths 61, 62, flow paths 63, 64, and flow paths 65, 66, respectively. In order to prevent backflow of pressure oil to the pump line 60, check valves 29 to 31 are arranged in the flow paths 61, 62, flow paths 63, 64, and flow paths 65, 66, respectively. The swing direction control valve 14 controls the flow of pressure oil supplied from the third hydraulic pump 3 to the swing motor 211. The third boom direction control valve 15 controls the flow of pressure oil supplied from the third hydraulic pump 3 to the boom cylinder 204a. The second attachment direction control valve 16 is used when a second special attachment equipped with a second actuator is attached in addition to the first special attachment, or when the first special attachment is attached to the swing motor 211. attachment When a second special attachment having two actuators, a first actuator and a second actuator, is mounted instead of the first actuator, the pump line 60 is used to control the flow of pressurized oil supplied to the second actuator. The pump line 60 is connected to the hydraulic oil tank 5 via the main relief valve 20 to protect the circuit from an excessive pressure rise. The pump line 60 is connected to the hydraulic oil tank 5 via the bleed-off valve 37 to discharge excess discharge oil from the hydraulic pump 3.

[0026] The pump line 60 is connected to the discharge pressure (pump pressure P Pmp3 The pressure sensor 85 that detects the pressure of the supply port of the swing motor 211 (swing meter-in pressure P MISwg ) or the pressure at the discharge port (swivel meter-out pressure P MOSwg The flow paths 72, 73 connecting the boom cylinder 204a and the boom direction control valves 9, 10, 15 are provided with pressure sensors 86, 87 for detecting the pressure of the supply port of the boom cylinder 204a (boom meter-in pressure P MIBm ) are provided. The output values ​​of the pressure sensors 85 to 89 are input to a controller 94.

[0027] The directional control valves 6 to 13, 15, and 16 other than the swing directional control valve 14 have opening characteristics shown in Fig. 3. In Fig. 3, the meter-in opening area increases from zero to the maximum opening area according to the spool displacement. Similarly, the meter-out opening area increases from zero to the maximum opening area according to the spool displacement. product However, the area increases more than the meter-in opening area relative to the spool displacement. big This makes it possible to control the actuator drive speed with the meter-in opening.

[0028] The swing direction control valve 14 has an opening characteristic shown in Fig. 4. In Fig. 4, the meter-in opening area varies from zero to the maximum opening area depending on the spool displacement. product The meter-out opening area also increases from zero to the maximum opening area according to the spool displacement. product However, it is set to a value smaller than the meter-in opening area relative to the spool displacement. This makes it possible to control the back pressure of the swing motor 211 by the meter-out opening.

[0029] 2B, a discharge port of a pilot pump 91 is connected to a hydraulic oil tank 5 via a pilot relief valve 92 for generating a pilot primary pressure, and is also connected to one input port of each of solenoid valves 93a to 93f built into a solenoid valve unit 93 via a flow path 80. The other input ports of the solenoid valves 93a to 93f are connected to the hydraulic oil tank 5 via a flow path 81. The solenoid valves 93a to 93f each reduce the pilot primary pressure in response to a command signal from a controller 94, and output it as a command pressure.

[0030] The output port of the solenoid valve 93a is 3 Hydraulic pump 3 Regulator flow control command pressure port 3a The output ports of the solenoid valves 93b and 93c are connected to the 3 Boom Directional Control Valve 15 The output ports of the solenoid valves 93d and 93e are connected to the pilot ports of the Swing directional control valve 14The output port of the solenoid valve 93f is connected to the command pressure port 37a of the bleed-off valve 37.

[0031] In order to simplify the explanation, the solenoid valves for the flow rate control command pressure ports 1a, 2a of the regulators of the first hydraulic pump 1 and the second hydraulic pump 2, the solenoid valve for the travel right directional control valve 6, the solenoid valve for the bucket directional control valve 7, the solenoid valve for the second arm directional control valve 8, the solenoid valve for the first boom directional control valve 9, the solenoid valve for the second boom directional control valve 10, the solenoid valve for the first arm directional control valve 11, the solenoid valve for the first attachment directional control valve 12, the solenoid valve for the travel left directional control valve 13, the solenoid valve for the second attachment directional control valve 16, and the solenoid valves for the bleed-off valves 35, 36 are not shown in the illustration.

[0032] The hydraulic drive unit 902 is equipped with a boom operation lever 95a capable of switching the first boom directional control valve 9, the second boom directional control valve 10, and the third boom directional control valve 15, and a swing operation lever 95b capable of switching the swing directional control valve 14. For the sake of simplicity of explanation, the following are provided: a right travel operation lever for switching the right travel directional control valve 6, a bucket operation lever for switching the bucket directional control valve 7, an arm operation lever for switching the first arm directional control valve 11 and the second arm directional control valve 8, a first attachment operation lever for switching the first attachment directional control valve 12, and a left travel operation lever for switching the left travel directional control valve 13. , No. The second attachment operating lever for switching the second attachment directional control valve 16 is not shown in the figure.

[0033] The hydraulic drive device 902 includes a controller 94. The controller 94 outputs command signals to solenoid valves 93a to 93f (including solenoid valves not shown) of the solenoid valve unit 93 in accordance with the input amounts of operation levers 95a and 95b.

[0034] Fig. 5 is a functional block diagram of the controller 94. In Fig. 5, the controller 94 has a boom target flow rate calculation unit 94a, a swing target flow rate calculation unit 94b, a bleed-off valve target opening calculation unit 94c, an estimated bleed-off flow rate calculation unit 94d, a pump target flow rate calculation unit 94e, a pump control command output unit 94f, a boom direction control valve target meter-in opening calculation unit 94g, a boom direction control valve control command output unit 94h, a required torque calculation unit 94i, a gravity torque calculation unit 94j, an inertia torque calculation unit 94k, a target torque calculation unit 94l, a swing target meter-out pressure calculation unit 94m, a swing direction control valve target meter-out opening calculation unit 94n, a swing direction control valve control command output unit 94o, and a bleed-off valve control command output unit 94p.

[0035] The boom target flow rate calculation unit 94a calculates a target value (boom target flow rate Q TgtBm Specifically, the boom target flow rate Q corresponding to the operation lever input amount is calculated according to the boom flow rate characteristics for the operation lever input amount set in advance. TgtBm The swing target flow rate calculation unit 94b calculates a target value (swing target flow rate Q TgtSwg Specifically, the target turning flow rate Q corresponding to the operation lever input amount is calculated according to the turning flow rate characteristic for the operation lever input amount set in advance. TgtSwg The bleed-off valve target opening calculation unit 94c calculates the target opening area (bleed-off valve target opening area) of the bleed-off valves 35-37 based on the operating lever input amount. Specifically, the bleed-off valve target opening area corresponding to the operating lever input amount is calculated according to a preset bleed-off valve opening characteristic (shown in FIG. 6) relative to the operating lever input amount.

[0036] The estimated bleed-off flow rate calculation unit 94d calculates the pump pressure P obtained from the bleed-off valve target opening area calculated by the bleed-off valve target opening calculation unit 94c and the output value of the pressure sensor 85. Pmp3 Based on this, the estimated bleed-off flow rate (Estimated bleed-off flow rate Q EstBOThe pump target flow rate calculation unit 94e calculates the boom target flow rate Q TgtBm and the turning target flow rate Q calculated by the turning target flow rate calculation unit 94b TgtSwg and the estimated bleed-off flow rate Q calculated by the estimated bleed-off flow rate calculation unit 94d. EstBO Based on this, the pump target flow rate Q TgtPmp The pump control command output unit 94f calculates the pump target flow rate Q calculated by the pump target flow rate calculation unit 94e in accordance with the solenoid valve command signal characteristics for the pump flow rate that are set in advance. TgtPmp The control circuit 93a outputs a command signal (pump flow rate control command signal) corresponding to the command signal to the solenoid valve 93a.

[0037] The boom directional control valve target meter-in opening calculation unit 94g calculates the boom target flow rate Q TgtBm and the pump pressure P obtained from the output value of the pressure sensor 85 Pmp3 and the boom meter-in pressure P obtained from the output value of the pressure sensor 88 (89). MIBm Based on this, the target meter-in opening area A of the boom directional control valves 9, 10, and 15 is TgtMIBm The boom directional control valve control command output unit 94h calculates the target meter-in opening area A of the boom directional control valves 9, 10, 15 calculated by the boom directional control valve target meter-in opening calculation unit 94g in accordance with the solenoid valve command signal characteristics for the meter-in opening area of ​​the boom directional control valves 9, 10, 15 that are preset. TgtMIBm The controller 93 outputs a command signal (boom direction control valve control command signal) corresponding to the command signal to the solenoid valve 93b (93c).

[0038] The required torque calculation unit 94i calculates the required turning torque corresponding to the operation lever input amount according to a preset required turning torque characteristic for the operation lever input amount. The gravity torque calculation unit 94j converts the gravity component of the turning moment into the gravity torque T Gravity The inertia torque calculation unit 94k calculates the gravitational torque T Gravity Based on the output values ​​of the inertial measurement devices 212 to 216, the inertial component of the turning moment is calculated as the inertial torque TInertia The target torque calculation unit 94l calculates the turning torque required by the required torque calculation unit 94i and the gravitational torque T Gravity and the inertia torque T calculated by the inertia torque calculation unit 94k. Inertia Based on this, the target torque T of the swing motor 211 is calculated. TgtSwg Calculate.

[0039] The swing target meter-out pressure calculation unit 94m calculates the target torque T TgtSwg and the turning meter-in pressure P obtained from the output value of the pressure sensor 86 (87). MISwg Based on this, the turning target meter-out pressure P MOTgtSwg The swing direction control valve target meter-out opening calculation unit 94n calculates the swing target meter-out pressure P MOTgtSwg and the turning meter-out pressure P obtained from the output value of the pressure sensor 86 (87). MOSwg Based on this, the target meter-out opening area A of the swing direction control valve 14 is calculated. TgtMOSwg The swing direction control valve control command output unit 94o calculates the target meter-out opening area A of the swing direction control valve 14 calculated by the swing direction control valve target meter-out opening calculation unit 94n in accordance with the solenoid valve command signal characteristics for the meter-out opening area of ​​the swing direction control valve 14 that are set in advance. TgtMOSwg The rotation direction control valve 93d (93e) outputs a command signal (rotation direction control valve control command signal) corresponding to the rotation direction control valve 93d (93e).

[0040] The bleed-off valve control command output unit 94p outputs a command signal (bleed-off valve control command signal) corresponding to the bleed-off valve target opening area calculated by the bleed-off valve target opening calculation unit 94c to the solenoid valve 93f in accordance with the preset solenoid valve command signal characteristics for the opening area of ​​the bleed-off valves 35 to 37.

[0041] 7 is a flowchart showing the process related to the pump flow rate control of the controller 94. The following describes only the process related to the flow rate control of the third hydraulic pump 3. Note that the processes related to the flow rate control of the other hydraulic pumps are similar to this, so the description will be omitted.

[0042] The controller 94 first determines whether or not there is an operation lever input (step S101). The operation lever input here refers to an operation lever input for the actuators 204a, 211 connected to the pump line 60 of the third hydraulic pump 3. If it is determined in step S101 that there is no operation lever input (YES), the flow ends.

[0043] When it is determined in step S101 that there is an operation lever input (NO), the boom target flow rate calculation unit 94a calculates the boom target flow rate Q according to the operation lever input amount in accordance with the boom target flow rate characteristics for the operation lever input amount set in advance. TgtBm (Step S102A).

[0044] In parallel with step S102A, the turning target flow rate calculation unit 94b calculates the turning target flow rate Q according to the operating lever input amount in accordance with a preset turning target flow rate characteristic for the operating lever input amount. TgtSwg Although not shown in the figure, the target flow rates of the other actuators connected to the pump line 60 of the third hydraulic pump 3 are calculated in the same manner.

[0045] In parallel with steps S102A and S102B, the estimated bleed-off flow rate calculation unit 94d calculates the target opening area A of the bleed-off valve 37 calculated by the bleed-off valve target opening calculation unit 94c. TgtBO and the pump pressure P obtained from the output value of the pressure sensor 85 Pmp3 Using the above, the estimated bleed-off flow rate Q is calculated using the following formula: EstBO is calculated (step S103).

[0046]

number

[0047] Here, C d is the flow coefficient, P Tank is the tank pressure and ρ is the fluid density.

[0048] Following steps S102A, S102B, and S103, the pump target flow rate calculation unit 94e calculates the boom target flow rate Q TgtBm and the target flow rate Q TgtSwg and the estimated bleed-off flow rate Q EstBO Using the above, the pump target flow rate Q is calculated using the following formula: TgtPmp is calculated (step S104).

[0049]

number

[0050] Following step S104, the pump control command output unit 94f outputs the pump target flow rate Q calculated by the pump target flow rate calculation unit 94e in accordance with the solenoid valve command signal characteristics for the pump flow rate that have been set in advance. TgtPmp A command signal (pump flow rate control command signal) corresponding to the determined value is output to the solenoid valve 93a for controlling the pump flow rate of the third hydraulic pump 3 (step S105).

[0051] Following step S105, a command pressure is generated in the solenoid valve 93a for controlling the pump flow rate of the third hydraulic pump 3 (step S106), the tilt of the third hydraulic pump 3 is changed according to the command pressure (step S107), and the flow is terminated.

[0052] 8 is a flowchart showing the processing related to the opening control of the boom direction control valves 9, 10, and 15 by the controller 94. Only the processing related to the opening control of the third boom direction control valve 15 will be described below. The processing related to the opening control of the other directional control valves other than the swing direction control valve 14 is similar to this, so the description will be omitted.

[0053] The controller 94 first determines whether or not there is an operation lever input (step S201). If it is determined in step S201 that there is no operation lever input (YES), the flow ends.

[0054] When it is determined in step S201 that there is an operation lever input (NO), the boom target flow rate calculation unit 94a calculates the boom target flow rate Q according to the operation lever input amount in accordance with the boom target flow rate characteristics for the operation lever input amount set in advance. TgtBm is calculated (step S202).

[0055] Following step S202, the boom directional control valve target meter-in opening calculation unit 94g calculates the boom target flow rate Q TgtBm and the pump pressure P of the third hydraulic pump 3 obtained from the output value of the pressure sensor 85. Pmp3 and the boom meter-in pressure P obtained from the output value of the pressure sensor 88 (89). MIBm Based on this, the target meter-in opening area A of the third boom directional control valve 15 is calculated using the following formula: TgtMIBm is calculated (step S203).

[0056]

number

[0057] Here, C d is the flow coefficient and ρ is the fluid density.

[0058] Following step S203, the boom directional control valve control command output unit 94h outputs the target meter-in opening area A calculated by the boom directional control valve target meter-in opening calculation unit 94g according to the solenoid valve command signal characteristics for the meter-in opening area of ​​the third boom directional control valve 15 that are preset. TgtMIBm A command signal corresponding to the command is output to the solenoid valve 93b (93c) for the third boom direction control valve 15 (step S204).

[0059] Following step S204, a command pressure is generated in the solenoid valves 93b, 93c for the third boom direction control valve 15 (step S205), the third boom direction control valve 15 is opened in response to the command pressure (step S206), and the flow is terminated.

[0060] FIG. 9 is a flowchart showing the process of the controller 94 for controlling the opening of the swing direction control valve 14.

[0061] The controller 94 first determines whether or not there is a turning operation lever input (step S301). S301 If it is determined that there is no turning operation lever input (YES) in step 4, the flow is terminated.

[0062] If it is determined in step S301 that there is a turning operation lever input (NO), the required torque calculation unit 94i calculates the turning required torque T according to the operation lever input amount in accordance with a turning required torque characteristic relative to the turning operation lever input amount that is set in advance. ReqSwg is calculated (step S302).

[0063] In parallel with step S302, the gravity torque calculation unit 94j calculates the gravity component of the turning moment as the gravity torque T Gravity (step S303).

[0064] Following step S303, the inertia torque calculation unit 94k calculates the gravitational torque T Gravity Based on the output values ​​of the inertial measurement devices 212 to 216, the inertial component of the turning moment is calculated as the inertial torque T Inertia (step S304).

[0065] Following steps S302 and S304, the target torque calculation unit 94l calculates the required turning torque T ReqSwg and the gravitational torque T calculated by the gravitational torque calculation unit 94j. Gravity and the inertia torque T calculated by the inertia torque calculation unit 94k.Inertia Using the above, the target torque T of the swing motor 211 is calculated by the following formula: TgtSwg is calculated (step S305).

[0066]

number

[0067] Here, the required turning torque T ReqSwg Torque in the same rotational direction is considered positive.

[0068] Following step S305, the swing target meter-out pressure calculation unit 94m calculates the target torque T TgtSwg and the turning meter-in pressure P obtained from the output value of the pressure sensor 86 (87). MISwg Using the above, the target meter-out pressure P is calculated using the following formula: MOTgtSwg is calculated (step S306).

[0069]

number

[0070] Here, q is the motor capacity and η is the transmission efficiency.

[0071] Following step S306, the swing direction control valve target meter-out opening calculation unit 94n calculates the swing target meter-out pressure calculated by the swing target meter-out pressure calculation unit 94m. P MOTgtSwg and the turning meter-out pressure P obtained from the output value of the pressure sensor 86 (87). MOSwg The target meter-out opening area A of the swing direction control valve 14 is set so that the difference between TgtMOSwg is calculated (step S307).

[0072] Following step S307, the swing direction control valve control command output unit 94o outputs the target meter-out opening area A calculated by the swing direction control valve target meter-out opening calculation unit 94n according to the solenoid valve command signal characteristics for the meter-out opening area of ​​the swing direction control valve 14 that are set in advance. TgtMOSwg A command signal (swing direction control valve control command signal) corresponding to the swing direction control valve 14 is output to the solenoid valve 93d (93e) for the swing direction control valve 14 (step S308).

[0073] Following step S308, the solenoid valve 93d (93e) is caused to generate a command pressure for the swing direction control valve 14 (step S309), and the swing direction control valve 14 is caused to open in response to the command pressure (step S310), after which the flow ends.

[0074] FIG. 10 shows the bleed-off valves 35 to 37 of the controller 94. opening 1 is a flowchart showing processing related to control. Only the processing related to the opening control of the bleed-off valve 37 provided in the pump line 60 of the third hydraulic pump 3 will be described below. The processing related to the opening control of the other bleed-off valves is similar to this, so the description will be omitted.

[0075] The controller 94 first determines whether or not there is an operation lever input (step S401). The operation lever input here refers to an operation lever input for the actuators 204a, 211 connected to the pump line 60 of the third hydraulic pump 3. If it is determined in step S401 that there is no operation lever input (YES), the flow ends.

[0076] If it is determined in step S401 that there is an operating lever input (NO), the bleed-off valve target opening calculation unit 94c calculates the target opening area A of the bleed-off valve 37 according to the operating lever input amount in accordance with a preset bleed-off valve opening characteristic (shown in FIG. 6) relative to the operating lever input amount. TgtBO (Step S402) The control lever input amount referred to here corresponds to the maximum value of the control lever input amounts for the actuators connected to the same pump line.

[0077] Following step S402, the bleed-off valve control command output unit 94p determines the target opening area A of the bleed-off valve 37 according to the preset electromagnetic valve command signal characteristics for the opening area of ​​the bleed-off valve 37. TgtBO A command signal corresponding to the command is output to the solenoid valve 93f for the bleed-off valve 37 (step S403).

[0078] Following step S403, the solenoid valve 93f is caused to generate a command pressure for the bleed-off valve 37 (step S404). 37 (step S405), and the flow ends.

[0079] (operation) The operation of the hydraulic drive system 902 when a combined operation is performed to simultaneously drive the boom cylinder 204a and the swing motor 211 will be described below, including the operation of the third hydraulic pump 3, the third boom direction control valve 15, the swing direction control valve 14, and the bleed-off valve 37.

[0080] "Third hydraulic pump" The controller 94 determines the pump target flow rate Q of the third hydraulic pump 3 based on the input amount of the boom operation lever 95a and the swing operation lever 95b. TgtPmp Calculate the pump target flow rate Q TgtPmp The solenoid valve 93a generates a command pressure according to the command signal, and controls the discharge flow rate of the third hydraulic pump 3. control do.

[0081] "Third boom directional control valve" The controller 94 calculates a boom target flow rate Q based on the input amount of the boom operation lever 95a. TgtBm and the pump pressure P detected by the pressure sensor 85. Pmp3 and the boom meter-in pressure P detected by the pressure sensor 88 (89) MIBm Based on this, the target meter-in opening area A TgtMIBm Calculate the target meter-in opening area A TgtMIBmThe solenoid valve 93b (93c) generates a command pressure according to the command signal and controls the meter-in opening area of ​​the third boom direction control valve 15.

[0082] "Rotation directional control valve" The controller 94 controls the input amount of the turning operation lever 95b and the gravity torque T Gravity and inertia torque T Inertia The target torque T is calculated from TgtSwg and the turning meter-in pressure P detected by the pressure sensors 86 and 87. MISwg and turning meter out pressure P MOSwg Based on this, the target meter-out opening area A TgtMOSwg Calculate the target meter-out opening area A TgtMOSwg The solenoid valve 93d (93e) generates a command pressure according to the command signal and controls the meter-out opening area of ​​the swing direction control valve 14.

[0083] "Bleed-off valve" The controller 94 determines the target opening area A of the bleed-off valve 37 based on the input amount of the boom operation lever 95a and the swing operation lever 95b. TgtBO Calculate the target opening area A TgtBO The solenoid valve 93f generates a command pressure according to the command signal and controls the opening area of ​​the bleed-off valve 37.

[0084] (summary) In this embodiment, a working machine 901 is provided with a traveling body 201, a rotating body 202 rotatably attached on the traveling body 201, a working device 203 attached to the rotating body 202, a hydraulic oil tank 5, a variable displacement hydraulic pump 3 that draws in and discharges hydraulic oil from the hydraulic oil tank 5, a regulator 3a that controls the capacity of the hydraulic pump 3, an actuator 204a that drives the working device 203, a swing motor 211 that drives the swing body 202, an actuator directional control valve 15 that controls the flow of pressure oil supplied from the hydraulic pump 3 to the actuator 204a, a swing direction control valve 14 that controls the flow of pressure oil supplied from the hydraulic pump 3 to the swing motor 211, operation devices 95a, 95b that instruct the operation of the actuator 204a and the swing motor 211, and a controller 94 that controls the regulator 3a, the actuator directional control valve 15, and the swing direction control valve 14 in accordance with the input amount of the operation devices 95a, 95b. Pmp3 and a first pressure sensor 85 that detects the actuator meter-in pressure P MIBm A second pressure sensor that detects 88,89 and the pressure on the meter-in side of the swing motor 211, the swing meter-in pressure P MISwg and a third pressure sensor for detecting a swing meter-out pressure, which is the pressure on the meter-out side of the swing motor 211. 86,87 and posture sensors 212-216 for detecting the postures of the rotating body 202 and the working device 203. The actuator directional control valve 15 and the swing direction control valve 14 each have a meter-in opening and a meter-out opening formed in the same valve body. The actuator directional control valve 15 is formed so that the meter-in opening becomes smaller than the meter-out opening with respect to valve displacement, and the swing direction control valve 14 is formed so that the meter-out opening becomes smaller than the meter-in opening with respect to valve displacement. The controller 94 calculates an actuator target flow rate Q, which is a target value for the flow rate of pressure oil supplied from the hydraulic pump 3 to the actuator 204a, based on the input amounts of the operation devices 95a and 95b. TgtBm Based on the input amount of the operation devices 95a and 95b, a swing target flow rate QTgtSwg Calculate the actuator target flow rate Q TgtBm and the target flow rate Q TgtSwg Based on this, the target value of the discharge flow rate of the hydraulic pump 3 is set as the pump target flow rate Q TgtPmp Calculate the actuator target flow rate Q TgtBm and pump pressure P Pmp3 and actuator meter-in pressure P MIBm Based on this, a target meter-in opening area A, which is a target value of the meter-in opening area of ​​the actuator directional control valve 15, is calculated. TgtMIBm Based on the input amounts of the operation devices 95a and 95b and the output values ​​of the attitude sensors 212 to 216, a target torque T TgtSwg Calculate the target torque T TgtSwg and turning meter-in pressure P MISwg Based on this, the turning meter out pressure P MOSwg Goal value The target meter-out pressure P MOTgtSwg Calculate the turning target meter-out pressure P MOTgtSwg and turning meter out pressure P MOSwg Based on this, a target meter-out opening area A, which is a target value of the meter-out opening area of ​​the swing direction control valve 14, is calculated. TgtMOSwg Calculate the pump target flow rate Q TgtPmp The regulator 3a is controlled in accordance with the target meter-in opening area A TgtMIBm The actuator directional control valve 15 is controlled in accordance with the target meter-out opening area A TgtMOSwg The rotation direction control valve 14 is controlled in accordance with the rotation direction control valve 14.

[0085] According to this embodiment configured as described above, during combined operation in which the swing motor 211 and the other actuator 204a are driven simultaneously, the meter-in opening is adjusted according to the front-rear differential pressure of the boom direction control valves 9, 10, 15 to supply a target flow rate to the boom cylinder 204a, thereby making it possible to operate the boom 204 at a target speed. Also, by adjusting the meter-out opening of the swing direction control valve 14 to input a target torque to the swing motor 211, it is possible to prevent overshooting due to the inertia of the swing body 202. Furthermore, the pump target flow rate Q of the hydraulic pump 3 is adjusted according to the front-rear differential pressure of the boom direction control valves 9, 10, 15 to supply a target flow rate to the boom cylinder 204a, making it possible to operate the boom 204 at a target speed. TgtPmpis the boom target flow rate Q TgtBm and the target flow rate Q TgtSwg and a flow rate obtained by subtracting the supply flow rate to the boom cylinder 204a from the discharge flow rate of the hydraulic pump 3 is supplied to the swing motor 211, so that the swing body 202 can be operated at the target speed. This makes it possible to control the speed of the actuator 204a and the torque of the swing motor 211 during combined operation in which the swing motor 211 and the other actuator 204a are driven simultaneously, with a simple configuration using a directional control valve that performs meter-in opening control and meter-out opening control with the same valve body.

[0086] The work machine 901 in this embodiment is also equipped with a bleed-off valve 37 that discharges hydraulic oil discharged from the hydraulic pump 3 into the hydraulic oil tank 5, and the controller 94 determines a bleed-off valve target opening area A, which is a target value of the opening area of ​​the bleed-off valve 37, based on the input amounts of the operation devices 95a and 95b. TgtBO Calculate the bleed-off valve target opening area A TgtBO and pump pressure P Pmp3 Based on this, the estimated bleed-off flow rate Q EstBO Calculate the actuator target flow rate Q TgtBm and the target flow rate Q TgtSwg and the estimated bleed-off flow rate Q EstBO The sum of these is the pump target flow rate Q TgtPmp As a result, when the actuator 204a starts to operate, the excess oil discharged from the hydraulic pump 3 is discharged to the hydraulic oil tank 5, making it possible to prevent the actuator 204a from jumping out.

[0087] Although the embodiment of the present invention has been described above in detail, the present invention is not limited to the above-mentioned embodiment and includes various modified examples. For example, the above-mentioned examples are described in detail to easily explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described. [Explanation of symbols]

[0088] 1...First hydraulic pump, 1a...Flow control command pressure port (regulator), 2...Second hydraulic pump, 2a...Flow control command pressure port (regulator), 3...Third hydraulic pump, 3a...Flow control command pressure port (regulator), 5...Hydraulic oil tank, 6...Right travel directional control valve, 7...Bucket directional control valve, 8...Second arm directional control valve, 9...First boom directional control valve (actuator directional control valve), 10...Second boom directional control valve (actuator directional control valve), 11...First arm directional control valve, 12...First attachment directional control valve, 13... Travel left directional control valve, 14...swing directional control valve, 15...third boom directional control valve (actuator directional control valve), 16...second attachment directional control valve, 17...junction valve, 18-20...main relief valve, 21-32...check valve, 35-37...bleed-off valve, 37a...command pressure port, 40...pump line, 41-48...flow path, 50...pump line, 51-58...flow path, 60...pump line, 61-68...flow path, 70-73...flow path, 80,81...flow path, 85...pressure sensor (first pressure sensor), 86,87...pressure sensor (second 3 Pressure sensor), 88, 89...Pressure sensor (part 2pressure sensor), 91... pilot pump, 92... pilot relief valve, 93... solenoid valve unit, 93a to 93f... solenoid valve, 94... controller, 94a... boom target flow rate calculation unit, 94b... swing target flow rate calculation unit, 94c... bleed-off valve target opening calculation unit, 94d... estimated bleed-off flow rate calculation unit, 94e... pump target flow rate calculation unit, 94f... pump control command output unit, 94g... boom directional control valve target meter-in opening calculation unit, 94h... boom directional control valve control command output unit, 94i... required torque calculation unit, 94j... gravity torque calculation unit, 94k... inertia torque calculation unit, 94l... target torque calculation unit, 94m... swing target meter-out pressure calculation unit, 94n... swing directional control valve target meter-out opening calculation unit, 94o...swing direction control valve control command output section, 94p...bleed-off valve control command output section, 95a...boom operation lever (operation device), 95b...swing operation lever (operation device), 201...traveling body, 202...swinging body, 203...working device, 204...boom, 204a...boom cylinder (actuator), 205...arm, 205a...arm cylinder (actuator), 206...bucket, 206a...bucket cylinder (actuator), 207...operator's cab, 208...machine room, 209...counterweight, 210...control valve, 211...swing motor (actuator), 212-216...inertial measurement unit (attitude sensor), 901...hydraulic excavator (working machine), 902...hydraulic drive unit.

Claims

1. A running body, A rotating body rotatably attached on the traveling body; A working device attached to the rotating body; A hydraulic oil tank; A variable displacement hydraulic pump that draws in and discharges hydraulic oil from the hydraulic oil tank; A regulator for controlling the displacement of the hydraulic pump; An actuator that drives the working device; A rotation motor that drives the rotating body; an actuator directional control valve for controlling a flow of pressure oil supplied from the hydraulic pump to the actuator; a swing direction control valve for controlling a flow of pressure oil supplied from the hydraulic pump to the swing motor; an operating device that instructs the operation of the actuator and the rotation motor; A working machine including a controller that controls the regulator, the actuator directional control valve, and the swing direction control valve in accordance with an input amount of the operating device, A first pressure sensor for detecting a pump pressure which is a discharge pressure of the hydraulic pump; a second pressure sensor for detecting an actuator meter-in pressure, which is a pressure on a meter-in side of the actuator; a third pressure sensor for detecting a swing meter-in pressure which is a pressure on a meter-in side of the swing motor, and a swing meter-out pressure which is a pressure on a meter-out side of the swing motor; a posture sensor for detecting the postures of the rotating body and the working device; The actuator directional control valve and the swing directional control valve each have a meter-in opening and a meter-out opening formed in a single valve body, The actuator directional control valve is formed so that a meter-in opening is smaller than a meter-out opening with respect to valve displacement, The swing direction control valve is formed so that a meter-out opening is smaller than a meter-in opening with respect to valve displacement, The controller: calculating an actuator target flow rate, which is a target value of a flow rate of pressure oil supplied from the hydraulic pump to the actuator, based on an input amount of the operating device; Calculating a target swing flow rate, which is a target value of a flow rate of pressure oil supplied from the hydraulic pump to the swing motor, based on an input amount of the operating device; Calculating a pump target flow rate, which is a target value of a discharge flow rate of the hydraulic pump, based on the actuator target flow rate and the swing target flow rate; calculating a target meter-in opening area, which is a target value of a meter-in opening area of ​​the actuator directional control valve, based on the actuator target flow rate, the pump pressure, and the actuator meter-in pressure; calculating a target torque, which is a target value of an input torque to the swing motor, based on an input amount of the operation device and an output value of the attitude sensor; Calculating a turning target meter-out pressure, which is a target value of the turning meter-out pressure, based on the target torque and the turning meter-in pressure; A target meter-out opening area, which is a target value of a meter-out opening area of ​​the swing direction control valve, is calculated based on the swing target meter-out pressure and the swing meter-out pressure; controlling the regulator in response to the pump target flow rate; controlling the actuator directional control valve in accordance with the target meter-in opening area; The swing direction control valve is controlled in accordance with the target meter-out opening area. A working machine characterized by:

2. 2. The work machine according to claim 1, A bleed-off valve is provided to discharge hydraulic oil discharged from the hydraulic pump into the hydraulic oil tank. The controller: Calculating a bleed-off valve target opening area, which is a target value of the opening area of ​​the bleed-off valve, based on an input amount of the operating device; calculating an estimated bleed-off flow rate, which is an estimated value of a flow rate passing through the bleed-off valve, based on the bleed-off valve target opening area and the pump pressure; A sum of the actuator target flow rate, the rotation target flow rate, and the estimated bleed-off flow rate is calculated as the pump target flow rate. A working machine characterized by:

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