Construction machine

Abstract

This construction machine is provided with: a flow rate control valve as a hydraulic device that adjusts the flow rate supplied to a hydraulic cylinder that drives a work device; and a control device that controls the hydraulic cylinder so as to satisfy the condition that the work tool moves without exceeding the target surface. The control device calculates a target speed of the hydraulic cylinder at which the work tool satisfies the condition on the basis of information on the target surface and detection information from a detection device that detects the orientation of the work device, and controls the work tool when the target value of the hydraulic device corresponding to the calculated target speed is less than a lower limit value at which the accuracy of flow control can be ensured. On the basis of the limited speed of the hydraulic cylinder obtained from the lower limit value, a target speed of the hydraulic cylinder at which the work tool satisfies the condition is re-calculated, and the hydraulic device is controlled by a target value corresponding to the re-calculated target speed.

Description

Technical Field

[0001] This invention relates to construction machinery, and more specifically, to construction machinery that controls a hydraulically driven working device to operate under specified conditions. Background Technology

[0002] Hydraulic excavators and other construction machinery consist of a rotating body and a working device mounted on it. The rotating body, working device, and other driven components are driven by hydraulic actuators such as hydraulic motors and cylinders. The working device is a multi-joint device composed of multiple linkage components rotatably connected together. For example, it consists of a boom rotatably connected to the rotating body in a vertical direction, a stick rotatably connected to the front end of the boom in a vertical direction, and a bucket rotatably connected to the front end of the stick in a vertical direction. The boom, stick, and bucket are driven by boom cylinders, stick cylinders, and bucket cylinders, respectively. Manually operating the multiple linkage components that make up the working device to excavate a designated area is not easy and requires skilled operation from the operator.

[0003] Therefore, as an example of a countermeasure to facilitate such operations, the technology described in Patent Document 1 is known. The area-restricted excavation control device for construction machinery described in Patent Document 1 corrects the operating signals of the operating lever device associated with the front device (working device) through a first signal correction unit, thereby controlling the deceleration of the movement of the front device in the direction approaching the boundary of the set area. When the front device approaches the boundary of the set area, the movement in the approach direction is decelerated, thus enabling the front device to move along the boundary of the set area. As a result, the operator can perform stable and accurate operations regardless of their skill level.

[0004] However, the technology described in Patent Document 1 has the following problems. In the case of semi-automatic control of the front device (working device) based on instructions from a control device that corrects the operating signal of the lever device, it is important that the front end of the front device moves accurately along the target trajectory. For this purpose, it is necessary to ensure that the flow rate of hydraulic oil supplied to the hydraulic actuator driving the front device matches the target flow rate. In the area-restricted excavation control device described in Patent Document 1, the opening of the flow control valve is adjusted by controlling the control pressure (pilot pressure) of the flow control valve, thereby controlling the supply flow to the hydraulic actuator. However, even if the opening of the flow control valve can be accurately controlled, if the differential pressure across the flow control valve changes with the load variation of the front device (the load pressure variation of the hydraulic actuator), the flow rate of the hydraulic oil supplied to the hydraulic actuator via the flow control valve becomes unstable.

[0005] As a means of solving such a problem, for example, the technology described in Patent Document 2 has been proposed. In the hydraulic static drive system described in Patent Document 2, the flow rate of the pressure medium (hydraulic oil) supplied to the consuming machine (hydraulic actuator) is controlled by an adjusting valve (flow control valve) with a throttling function. The opening of the adjusting valve is adjusted according to the pressure drop (differential pressure) of the adjusting valve detected by a pressure sensor, so as to supply the volumetric flow rate requested by the setting device to the consuming machine. Thus, even if the load pressure of the consuming machine or the supply pressure of the hydraulic pump changes, the flow rate of the pressure medium supplied to the consuming machine can be accurately controlled without the need for an additional pressure compensator.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 1995 / 030059

[0009] Patent Document 2: Japanese Patent Application Publication No. 2014-98487 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] When performing control that restricts the movement of the working device (front unit) to a designated area (hereinafter referred to as the area restriction control of the working device), as described in Patent Document 1, to improve the accuracy of flow control of the hydraulic actuator driving the working device, the technology described in Patent Document 2, which adjusts the opening area of ​​the flow control valve (adjusting valve) based on the differential pressure before and after the hydraulic actuator, is considered. However, when the hydraulic actuator is driven at low speed during area restriction control of the working device, the accuracy of flow control may decrease. When the accuracy of flow control of the hydraulic actuator decreases, it becomes difficult to accurately control the movement of the working device. This is based on reasons such as the following.

[0012] When the throttling part of a flow control valve that controls flow rate, such as the regulating valve described in Patent Document 2, is defined as an orifice, the flow rate Q of the flow control valve is expressed by the following formula (1).

[0013]

[0014] Here, A is the opening area of ​​the flow control valve, ΔP is the differential pressure across the flow control valve, ρ is the density of the working oil, and Cd is the flow coefficient of the flow control valve.

[0015] In the technology described in Patent Document 2, the opening amount of the flow control valve is controlled by the control pressure (pilot pressure) generated by the pilot control valve corresponding to the control of the electronic control device. If there is an error between the control pressure generated by the pilot control valve and the target control pressure corresponding to the control of the electronic control device, the opening amount of the flow control valve will deviate accordingly. When the flow control valve is driven under low flow conditions in order to drive the hydraulic actuator at a low speed, it is known from the above equation (1) that the opening area (A) of the flow control valve needs to be controlled in a small area. In this case, the error of the control pressure input to the flow control valve has a greater impact on the flow rate of the flow control valve. Therefore, when the hydraulic actuator is driven at a low speed, the accuracy of the flow control of the hydraulic actuator is reduced, and thus, accurate control of the operation of the working device may become difficult.

[0016] The present invention was made to solve the above-mentioned problems, and its purpose is to provide an engineering machine that can accurately control the operation of the working device even when the hydraulic actuator is driven at low speed in the area restriction control of the working device.

[0017] Methods for solving problems

[0018] This application contains several means to solve the above-mentioned problems. One example of the invention includes: a working device comprising a working tool; at least one hydraulic actuator driving the working device; a hydraulic device capable of adjusting the flow rate of hydraulic oil supplied to the hydraulic actuator; a control device controlling the hydraulic actuator via the hydraulic device to satisfy the condition that the working tool moves without exceeding a target surface set as the working object; a posture detection device detecting the posture of the working device, wherein the control device, based on the detection information from the posture detection device and the target surface setting information, calculates the speed of the hydraulic actuator that causes the working tool to satisfy the condition as a target speed, and calculates and operates... The target value of the hydraulic equipment corresponding to the calculated target speed of the hydraulic actuator is used as the limit speed of the hydraulic actuator if the calculated target value of the hydraulic equipment is smaller than the lower limit value that can ensure the allowable accuracy of the hydraulic equipment for flow control. Based on the calculated limit speed of the hydraulic actuator, the target speed of the hydraulic actuator that makes the working tool meet the condition is recalculated. The target value of the hydraulic equipment is used as the control target to control the hydraulic equipment, corresponding to the recalculated target speed of the hydraulic actuator.

[0019] Invention Effects

[0020] According to one embodiment of the present invention, when the target value of the hydraulic device used to control and adjust the supply flow to the hydraulic actuator is lower than the lower limit value that can ensure the accuracy of flow control, the target value of the hydraulic device corresponding to the target speed of the hydraulic actuator calculated based on the limit speed of the hydraulic actuator calculated using the lower limit value is used as the control target. Therefore, even when the working device is operated by low-speed drive of the hydraulic actuator in the area restriction control of the working device, the accuracy of flow control of the hydraulic actuator can be prevented from decreasing, and the operation of the working device can be accurately controlled.

[0021] Other issues, structures, and effects not mentioned above will be clarified through the following description of the implementation methods. Attached Figure Description

[0022] Figure 1 This is a side view of a hydraulic excavator, which is an example of an engineering machine according to the first embodiment of the present invention.

[0023] Figure 2 It means Figure 1 The hydraulic circuit diagram of the main structure (main circuit) of the hydraulic system of the engineering machinery of the first embodiment shown.

[0024] Figure 3 It means Figure 1 The hydraulic circuit diagram of the pilot circuit in the hydraulic system of the engineering machinery of the first embodiment shown.

[0025] Figure 4 This is a block diagram illustrating the hardware and functional structure of the control device in the engineering machinery according to the first embodiment.

[0026] Figure 5 It means Figure 2 The diagram illustrates the structural elements of the hydraulic system of the engineering machinery in the first embodiment, specifically the factors that reduce the accuracy of flow control in the flow control valve.

[0027] Figure 6 It means Figure 4 The diagram shows a block diagram of the subdivision processing function of the flow control valve target opening calculation unit in the control device of the engineering machinery according to the first embodiment.

[0028] Figure 7 yes Figure 4 A flowchart illustrating an example of the control sequence of the control device for the engineering machinery of the first embodiment.

[0029] Figure 8 This is an explanatory diagram showing the operation and effects of the engineering machinery according to the first embodiment.

[0030] Figure 9This is a block diagram illustrating the hardware and functional structure of the control device in the engineering machinery according to the second embodiment of the present invention.

[0031] Figure 10 This is a diagram showing the factors that reduce the accuracy of flow control in the hydraulic pump, a structural element of the hydraulic system of the engineering machinery as described in the second embodiment.

[0032] Figure 11 yes Figure 9 A block diagram showing the subdivision processing function of the pump target flow calculation unit in the control device of the engineering machinery of the second embodiment.

[0033] Figure 12 yes Figure 9 A flowchart illustrating an example of the control sequence of the control device for the engineering machinery according to the second embodiment. Detailed Implementation

[0034] Hereinafter, embodiments of the construction machinery of the present invention will be described using the accompanying drawings. In this embodiment, a hydraulic excavator will be used as an example of construction machinery. Furthermore, the directions described in this specification refer to the directions observed from the perspective of the operator riding in the construction machinery.

[0035] [First Implementation Method]

[0036] First, use Figure 1 The structure of a hydraulic excavator, which is the first embodiment of the engineering machinery of the present invention, will be described. Figure 1 This is a side view of a hydraulic excavator, which is an example of an engineering machine according to the first embodiment.

[0037] exist Figure 1 In this hydraulic excavator 1, it generally consists of a self-propelled traveling body 2, a rotating body 3 rotatably mounted on the traveling body 2, and a working device 4 rotatably mounted on the rotating body 3 in the vertical direction. The traveling body 2 and the rotating body 3 constitute the body of the hydraulic excavator 1 as construction machinery. The rotating body 3 is configured to be powered by a rotary motor 6 (also described later) containing a hydraulic actuator. Figure 2 The rotating device rotates relative to the traveling body 2.

[0038] The vehicle body 2 has tracked driving devices 8 on the left and right (only one is shown in the figure). The left and right driving devices 8 are driven by driving motors 9 (only the left driving motor is shown in the figure) which are hydraulic actuators.

[0039] The rotating body 3 comprises: a rotating frame 11, which is rotatably mounted on the traveling body 2 as a support structure; a driver's cab 12, which is disposed on the left front side of the rotating frame 11; a counterweight 13, which is disposed at the rear end of the rotating frame 11; and a machine room 14, which is disposed between the driver's cab 12 and the counterweight 13. The driver's cab 12 is equipped with a driver's seat (not shown) for the operator, and operating devices 141 and 142 (described later). Figure 3 The counterweight 13 is used to achieve weight balance with the working device 4. The machine room 14 houses the prime mover (not shown), hydraulic pump 31, hydraulic pump 32, and hydraulic pump 33 (described later). Figure 2 ), pilot pump 111 (see below) Figure 3 Various devices, including the multiple directional control valves 36-46 (described later) and the control valve block 15, which is an assembly of flow control valves 51-59.

[0040] The working device 4 is a multi-joint working mechanism used for excavation and other operations, and includes three linkage components: a boom 21, a stick 22, and a bucket 23 as a working tool. The base end of the boom 21 is rotatably mounted to the front of the rotating body 3. The base end of the stick 22 is rotatably mounted to the front end of the boom 21. The base end of the bucket 23 is rotatably mounted to the front end of the stick 22. The boom 21, stick 22, and bucket 23, as driven components, are respectively powered by a pair of hydraulic actuators: a boom cylinder 25, a stick cylinder 26, and a bucket cylinder 27 (described later). Figure 2 )drive.

[0041] Inertial measurement units (IMUs) 131, 132, and 133 are provided in the working device 4 as detection devices for detecting the postures and motion states of the boom 21, stick 22, and bucket 23. IMUs 131, 132, and 13 are respectively installed in the connecting rod components connected to the boom 21, stick 22, and bucket 23. An inertial measurement unit (IMU) 134 is provided in the rotating body 3 to detect the posture and motion state of the machine body containing the rotating body 3, and an inertial measurement unit (IMU) 135 is provided to detect the rotational speed of the rotating body 3. Each IMU 131, 132, 133, 134, and 135 transmits the detection signal corresponding to the detected value (information related to posture and motion state) to the control device 200 (described later). Figure 3 Output. In addition, the detection device for detecting the posture and motion state of the detection work device 4 can be replaced by a tilt sensor, rotation angle sensor or stroke sensor, etc.

[0042] Next, use Figure 2 and Figure 3The structure of the hydraulic system of the engineering machinery of the first embodiment is described. Figure 2 It means Figure 1 The hydraulic circuit diagram of the main structure (main circuit) of the hydraulic system of the engineering machinery of the first embodiment shown. Figure 3 It means Figure 1 The hydraulic circuit diagram shows the structure of the pilot circuit in the hydraulic system of the engineering machinery of the first embodiment.

[0043] exist Figure 2 In this context, the hydraulic excavator 1 comprises a hydraulically driven traveling body 2, a rotating body 3, and a working device 4 (see reference). Figure 1 The hydraulic system 30 is a hydraulic system for the driven body. The hydraulic system 30 includes three main pumps: a first hydraulic pump 31, a second hydraulic pump 32, and a third hydraulic pump 33, as well as a working oil tank 34 for storing working oil.

[0044] Three main pumps 31, 32, and 33 are driven by a prime mover (not shown). The first hydraulic pump 31, the second hydraulic pump 32, and the third hydraulic pump 33 are, for example, variable-capacity hydraulic pumps, and each has a first adjuster, a second adjuster, and a third adjuster for adjusting the tilt angle of the swashplate or swashplate. The first adjuster includes a pilot circuit 110 (see reference 110) described later. Figure 3 The first command pressure port 31a receives the command pressure from the pilot circuit 110. The second regulator includes a second command pressure port 32a that receives the command pressure PiP2 from the pilot circuit 110. The third regulator includes a third command pressure port 33a that receives the command pressure from the pilot circuit 110.

[0045] The first discharge line 71 of the first hydraulic pump 31 is connected to the working oil tank 34 via the first central bypass line 72, and is also connected to the working oil tank 34 via the main relief valve 48 to protect the hydraulic circuit from excessive pressure rise. On the first central bypass line 72, from the upstream side, a right-travel directional control valve 36, a bucket directional control valve 37, a second stick directional control valve 38, a first boom directional control valve 39, and a first central bypass shut-off valve 61 (hereinafter referred to as the first CB shut-off valve) are sequentially arranged. The bucket directional control valve 37, the second stick directional control valve 38, and the first boom directional control valve 39 are connected in parallel via first oil passages 74 and 75, second oil passages 76 and 77, and third oil passages 78 and 79, respectively, relative to a first parallel line 73 branching from a portion of the first central bypass line 72 connecting the right-travel directional control valve 36 and the bucket directional control valve 37.

[0046] The right-hand travel directional control valve 36 controls the flow of hydraulic oil supplied from the first hydraulic pump 31 to the right-hand travel motor (not shown) of a pair of travel motors, and also controls the flow of hydraulic oil discharged from the right-hand travel motor to the working oil tank 34. The bucket directional control valve 37 controls the flow of hydraulic oil supplied from the first hydraulic pump 31 to the bucket cylinder 27, and also controls the flow of hydraulic oil discharged from the bucket cylinder 27 to the working oil tank 34. The second stick directional control valve 38 controls the flow of hydraulic oil supplied from the first hydraulic pump 31 to the stick cylinder 26, and also controls the flow of hydraulic oil discharged from the stick cylinder 26 to the working oil tank 34. The first boom directional control valve 39 controls the flow of hydraulic oil supplied from the first hydraulic pump 31 to the boom cylinder 25, and also controls the flow of hydraulic oil discharged from the boom cylinder 25 to the working oil tank 34. Each of the directional control valves 36-39 has pilot ports (not shown) at both ends, which are input with a command pressure (pilot secondary pressure) from the pilot circuit 110 described later. The first CB shut-off valve 61 controls the flow of hydraulic oil discharged from the first hydraulic pump 31 via the first central bypass line 72 to the working oil tank 34. The first CB shut-off valve 61 has a pilot port 61a, which is input with a command pressure (pilot secondary pressure) from the pilot circuit 110 described later.

[0047] The second discharge line 81 of the second hydraulic pump 32 is connected to the working oil tank 34 via the second central bypass line 82, and is also connected to the working oil tank 34 via the main relief valve 49 to protect the hydraulic circuit from excessive pressure rise. On the second central bypass line 82, starting from the upstream side, are sequentially arranged a second boom directional control valve 40, a first stick directional control valve 41, a first attachment directional control valve 42, a left travel directional control valve 43, and a second central bypass shut-off valve 62 (hereinafter referred to as the second CB shut-off valve). The second boom directional control valve 40, the first stick directional control valve 41, the first attachment directional control valve 42, and the left travel directional control valve 43 are respectively connected in parallel to the second parallel line 83 connected to the second discharge line 81 via first oil passages 84 and 85, second oil passages 86 and 87, third oil passages 88 and 89, and fourth oil passage 90.

[0048] The second boom uses a directional control valve 40 to control the flow of hydraulic oil supplied from the second hydraulic pump 32 to the boom cylinder 25, and also controls the flow of hydraulic oil discharged from the boom cylinder 25 to the working oil tank 34. The first stick uses a directional control valve 41 to control the flow of hydraulic oil supplied from the second hydraulic pump 32 to the stick cylinder 26, and also controls the flow of hydraulic oil discharged from the stick cylinder 26 to the working oil tank 34. The first attachment uses a directional control valve 42 to replace the bucket 23 (see reference). Figure 1In the case where a first special attachment (not shown) such as a crusher or grab is installed on the bucket 23, the flow of hydraulic oil supplied from the second hydraulic pump 32 to the first special hydraulic actuator (not shown) that drives the first special attachment is controlled, and the flow of hydraulic oil discharged from the first special hydraulic actuator to the working oil tank 34 is also controlled. The left-side travel directional control valve 43 controls the flow of hydraulic oil from the second hydraulic pump 32 to the left travel motor 9 (see reference) of the pair of travel motors. Figure 1 The flow of hydraulic oil supplied by the second hydraulic pump 32 is controlled, as is the flow of hydraulic oil discharged from the left travel motor 9 to the working oil tank 34. Each directional control valve 40-43 has a pilot port at both ends, which is input with a command pressure (pilot secondary pressure) from the pilot circuit 110 described later (only the directional control valves 41: 41a, 41b for the first stick are shown). The second CB shut-off valve 62 controls the flow of hydraulic oil discharged from the second hydraulic pump 32 to the working oil tank 34 via the second central bypass line 82. The second CB shut-off valve 62 has a pilot port 62a, which is input with a command pressure PiC2 (pilot secondary pressure) from the pilot circuit 110 described later.

[0049] The fourth oil circuit 90 is connected to the first discharge line 71 of the first hydraulic pump 31 via the connecting line 80. A confluence valve 65 and a check valve 66 are installed on the connecting line 80. The confluence valve 65 controls the supply of hydraulic oil from the first hydraulic pump 31 from the connecting line 80 to the fourth oil circuit 90, enabling the hydraulic oil from the first hydraulic pump 31 to merge with the hydraulic oil from the second hydraulic pump 32 and supply it to the left-hand drive motor 9. The check valve 66 allows hydraulic oil to flow from the connecting line 80 to the fourth oil circuit 90, while preventing hydraulic oil from flowing from the second parallel line 83 and the fourth oil circuit 90 to the connecting line 80.

[0050] A check valve 67 is provided in the section of the second parallel line 83 between the connection point with the third oil circuit 88 and the connection point with the fourth oil circuit 90. The check valve 67 allows flow from the second parallel line 83 to the fourth oil circuit 90, but prevents flow from the directional control valves 40, 41, and 42 other than the directional control valve 43 for leftward travel from the connecting line 80.

[0051] The third discharge line 91 of the third hydraulic pump 33 is connected to the working oil tank 34 via the third central bypass line 92, and is also connected to the working oil tank 34 via the main relief valve 50 to protect the hydraulic circuit from excessive pressure rise. On the third central bypass line 92, from upstream, are sequentially arranged a rotation directional control valve 44, a third boom directional control valve 45, a second accessory directional control valve 46, and a third central bypass shut-off valve 63 (hereinafter referred to as the third CB shut-off valve). The rotation directional control valve 44, the third boom directional control valve 45, and the second accessory directional control valve 46 are respectively connected in parallel to the third parallel line 93, which is connected to the third discharge line 91, via first oil passages 94 and 95, second oil passages 96 and 97, and third oil passages 98 and 99.

[0052] The rotation directional control valve 44 controls the flow of hydraulic oil supplied from the third hydraulic pump 33 to the rotary motor 6, and also controls the flow of hydraulic oil discharged from the rotary motor 6 to the working oil tank 34. The third boom directional control valve 45 controls the flow of hydraulic oil supplied from the third hydraulic pump 33 to the boom cylinder 25, and also controls the flow of hydraulic oil discharged from the boom cylinder 25 to the working oil tank 34. The second attachment directional control valve 46 controls the flow of hydraulic oil supplied to the second special hydraulic actuator (not shown) that drives the second special attachment, and also controls the flow of hydraulic oil discharged from the second special hydraulic actuator to the working oil tank 34, when the second attachment replaces the bucket 23 or is equipped with a second special actuator (not shown) in addition to the first special attachment, or when the second special attachment is equipped with both the first and second special actuators, replacing the first special actuator. Each of the directional control valves 44-46 has a pilot port (not shown) at both ends, which is input with a command pressure (pilot secondary pressure) from the pilot circuit 110 described later. The third CB shut-off valve 63 controls the flow of hydraulic oil discharged from the third hydraulic pump 33 to the working oil tank 34 via the third central bypass line 92. The third CB shut-off valve 63 has a pilot port 63a, which is input with a command pressure (pilot secondary pressure) from the pilot circuit 110 described later.

[0053] Additionally, bucket flow control valve 51, second stick flow control valve 52, and first boom flow control valve 53 are respectively installed on the first oil lines 74, 75, second oil lines 76, 77, and third oil lines 78, 79, which connect the bucket directional control valve 37, the second stick directional control valve 38, and the first boom directional control valve 39 to the first parallel pipeline 73. Bucket flow control valve 51 controls the flow rate of hydraulic oil supplied from the first hydraulic pump 31 to the bucket cylinder 27 via bucket directional control valve 37 (pump port). Second stick flow control valve 52 controls the flow rate of hydraulic oil supplied from the first hydraulic pump 31 to the stick cylinder 26 via second stick directional control valve 38. First boom flow control valve 53 controls the flow rate of hydraulic oil supplied from the first hydraulic pump 31 to the boom cylinder 25 via first boom directional control valve 39.

[0054] On the first oil circuits 84, 85, the second oil circuits 86, 87, and the third oil circuits 88, 89, which connect the second boom directional control valve 40, the first stick directional control valve 41, and the first accessory directional control valve 42 to the second parallel pipeline 83, respectively, there are a second boom flow control valve 54, a first stick flow control valve 55, and a first accessory flow control valve 56. The second boom flow control valve 54 controls the flow rate of hydraulic oil supplied from the second hydraulic pump 32 to the boom cylinder 25 via the second boom directional control valve 40 (pump port). The first stick flow control valve 55 controls the flow rate of hydraulic oil supplied from the second hydraulic pump 32 to the stick cylinder 26 via the first stick directional control valve 41. The first accessory flow control valve 56 controls the flow rate of hydraulic oil supplied from the second hydraulic pump 32 to the first special actuator (not shown) via the first accessory directional control valve 42.

[0055] On the first oil circuits 94 and 95, the second oil circuits 96 and 97, and the third oil circuits 98 and 99, which connect the rotation directional control valve 44, the third boom directional control valve 45, and the second accessory directional control valve 46 to the third parallel pipeline 93, respectively, there are rotation flow control valves 57, third boom flow control valves 58, and second accessory flow control valves 59. The rotation flow control valve 57 controls the flow rate of hydraulic oil supplied from the third hydraulic pump 33 to the rotary motor 6 via the rotation directional control valve 44 (pump port). The third boom flow control valve 58 controls the flow rate of hydraulic oil supplied from the third hydraulic pump 33 to the boom cylinder 25 via the third boom directional control valve 45. The second accessory flow control valve 59 controls the flow rate of hydraulic oil supplied from the third hydraulic pump 33 to the second special actuator (not shown) via the second accessory directional control valve 46.

[0056] All flow control valves 51-59 have the same structure. Figure 2The diagram only shows the structure of the flow control valve 55 for the first boom, omitting the structures of other flow control valves 51-54 and 56-59. Here, only the structure of the flow control valve 55 for the first boom is described.

[0057] The flow control valve 55 for the first boom is, for example, a seat-type flow control valve, which has superior responsiveness compared to a spool-type flow control valve. The flow control valve 55 includes: a seat-type valve core 551, which forms a variable throttling section between a primary side second oil passage 86 and a secondary side second oil passage 87; a control variable throttling section 552, which is disposed on the valve core 551 in connection with the primary side (second oil passage 86); a pilot line 553, which connects the downstream side of the control variable throttling section 552 to the secondary side (second oil passage 87) of the valve core 551; and a pilot variable throttling section 554, which is disposed on the pilot line 553. The housing housing incorporating the valve core 551 includes: a first pressure chamber 555 formed at the connection between the valve core 551 (variable throttling section) and a second oil passage 86 serving as the primary side; a second pressure chamber 556 formed at the connection between the valve core 551 (variable throttling section) and a second oil passage 87 serving as the secondary side; and a third pressure chamber 557 configured to communicate with the first pressure chamber 555 via a control variable throttling section 552. The control variable throttling section 552 is connected to the first pressure chamber 555 via an oil passage 558 formed inside the valve core 551, and is configured such that the opening area of ​​the third pressure chamber 557 varies according to the amount of movement of the valve core 551. The pilot variable throttling section 554 has a pilot port 554p that receives a command pressure PiFam1 (pilot secondary pressure) generated according to the command of the control device 200 described later, and adjusts the opening amount according to the pilot pressure input to the pilot port 554p.

[0058] In the flow control valve 55, the movement of the valve core 551 is determined by the pilot flow rate through the pilot line 553, which is controlled by the action of the variable throttle section 552. The pilot flow rate of the pilot line 553 is controlled by the opening of the pilot variable throttle section 554. Thus, the movement of the valve core 551 can be controlled by the opening of the pilot variable throttle section 554, which controls the pilot flow rate of the pilot line 553. That is, the flow control valve 55 is configured to control the flow rate of hydraulic oil supplied to the directional control valve 41 for the first boom via the second oil passages 86 and 87, based on the opening of the pilot variable throttle section 554.

[0059] exist Figure 3 In the hydraulic system 30, there are directional control valves 36-46 and flow control valves 51-59 for controlling the hydraulically piloted system (see reference). Figure 2 The drive of the hydraulic pumps and the control of each hydraulic pump 31~33 (refer to) Figure 2The pilot circuit 110 has a pump capacity of 110. The pilot circuit 110 includes a pilot pump 111 as a pilot hydraulic power source. The pilot pump 111 is connected to the working oil tank 34 via a pilot relief valve 112 for generating pilot primary pressure, and is also connected to the electromagnetic proportional pressure reducing valves 113a, 113b, 113c, 113d, and 113e that constitute the electromagnetic valve unit 113 via a pilot line 114.

[0060] Electromagnetic proportional pressure reducing valve 113a is connected to the second command pressure port 32a of the second regulator of the second hydraulic pump 32. Based on commands from the control device 200 (described later), it reduces the discharge pressure (pilot primary pressure) of the pilot pump 111 to generate a pilot secondary pressure PiP2, which serves as the command pressure. Electromagnetic proportional pressure reducing valves 113b and 113c are connected to the pilot ports 41a and 41b of the first stick directional control valve 41. Based on commands from the control device 200, they reduce the discharge pressure of the pilot pump 111 to generate pilot secondary pressures PiAm1C and PiAm1D, which serve as the command pressure. Electromagnetic proportional pressure reducing valve 113d is connected to the pilot port 554p of the pilot variable throttle section 554 of the first stick flow control valve 55. Based on commands from the control device 200, it reduces the discharge pressure of the pilot pump 111 to generate a pilot secondary pressure PiFam1, which serves as the command pressure. The electromagnetic proportional pressure reducing valve 113e is connected to the pilot port 62a of the second CB shut-off valve 62. According to the command from the control device 200, it reduces the discharge pressure of the pilot pump 111 to generate the pilot secondary pressure PiC2 as the command pressure.

[0061] Furthermore, due to the increased complexity of the explanation, the electromagnetic proportional pressure reducing valves used for the command pressure ports 31a and 33a of the regulators of the first hydraulic pump 31 and the third hydraulic pump 33 are omitted from the illustration. The electromagnetic proportional pressure reducing valves used for directional control valves 36-40 and 42-46 (excluding the directional control valve 41 for the first boom) are also omitted from the illustration. The electromagnetic proportional pressure reducing valves used for flow control valves 51-54 and 56-59 (excluding the flow control valve 55 for the first boom) are also omitted from the illustration. The electromagnetic proportional pressure reducing valves used for CB shut-off valves 61 and 63 (excluding the second CB shut-off valve 62) are also omitted from the illustration.

[0062] exist Figure 2 and Figure 3In this system, a first pressure sensor 121, a second pressure sensor 122, and a third pressure sensor 123 are respectively installed on the first discharge line 71 of the first hydraulic pump 31, the second discharge line 81 of the second hydraulic pump 32, and the third discharge line 91 of the third hydraulic pump 33. The first pressure sensor 121, the second pressure sensor 122, and the third pressure sensor 123 detect the discharge pressure of the first hydraulic pump 31 (pressure upstream of flow control valves 51-53), the discharge pressure of the second hydraulic pump 32 (pressure upstream of flow control valves 54-56), and the discharge pressure of the third hydraulic pump 33 (pressure upstream of flow control valves 57-59), respectively. The first pressure sensor 121, the second pressure sensor 122, and the third pressure sensor 123 output detection signals corresponding to the detected pressure values ​​to the control device 200 described later.

[0063] Pressure sensors 124 are installed on a pair of actuator lines 101, 101 connecting the first boom directional control valve 39, the second boom directional control valve 40, the third boom directional control valve 45, and the boom cylinder 25, respectively, to detect the pressure (inlet throttling pressure and outlet throttling pressure) of the hydraulic oil supplied to and discharged from the boom cylinder 25. Each pressure sensor 124 also functions as a pressure sensor to detect the pressure downstream of the boom flow control valves 53, 54, and 58. Each pressure sensor 124 outputs a detection signal corresponding to the detected pressure value to the control device 200, which will be described later.

[0064] Pressure sensors 125 are installed on a pair of actuator lines 102, 102 connecting the second stick directional control valve 38 and the first stick directional control valve 41 to the stick cylinder 26. These lines detect the pressure (inlet throttling pressure and outlet throttling pressure) of the hydraulic oil supplied to and discharged from the stick cylinder 26. Each pressure sensor 125 also functions as a pressure sensor for detecting the pressure downstream of the stick flow control valves 52, 55. Each pressure sensor 125 outputs a detection signal corresponding to the detected pressure value to the control device 200, which will be described later.

[0065] Pressure sensors 126 are respectively installed on a pair of actuator lines 103, 103 connecting the bucket directional control valve 37 and the bucket cylinder 27 to detect the pressure (inlet throttling pressure and outlet throttling pressure) of the hydraulic oil supplied to and discharged from the bucket cylinder 27. Each pressure sensor 126 also functions as a sensor to detect the pressure downstream of the bucket flow control valve 51. Each pressure sensor 126 outputs a detection signal corresponding to the detected pressure value to the control device 200 described later.

[0066] Pressure sensors 127 are installed on a pair of actuator lines 104, 104 connecting the rotary directional control valve 44 and the rotary motor 6 to detect the pressure (inlet throttling pressure and outlet throttling pressure) of the hydraulic oil supplied to and discharged from the rotary motor 6. Each pressure sensor 127 also functions as a sensor to detect the pressure downstream of the rotary flow control valve 57. Each pressure sensor 127 outputs a detection signal corresponding to the detected pressure value to the control device 200, which will be described later.

[0067] Pressure sensors 121 and 124 constitute a pressure sensor for detecting the differential pressure across the flow control valve 53 for the first boom. Pressure sensors 121 and 125 constitute a pressure sensor for detecting the differential pressure across the flow control valve 52 for the second boom. Pressure sensors 121 and 126 constitute a pressure sensor for detecting the differential pressure across the flow control valve 51 for the bucket. Pressure sensors 122 and 124 constitute a pressure sensor for detecting the differential pressure across the flow control valve 54 for the second boom. Pressure sensors 122 and 125 constitute a pressure sensor for detecting the differential pressure across the flow control valve 55 for the first stick. Pressure sensors 123 and 124 constitute a pressure sensor for detecting the differential pressure across the flow control valve 58 for the third boom. Pressure sensors 123 and 127 constitute a pressure sensor for detecting the differential pressure across the flow control valve 57 for rotation.

[0068] The hydraulic system 30 includes operating devices comprising a boom operating lever 141 and a stick operating lever 142, which respectively indicate the movement of the boom 21 and the stick 22, which are driven bodies. The boom operating lever 141 can switch between the first boom directional control valve 39, the second boom directional control valve 40, and the third boom directional control valve 45, and outputs an operating signal (electrical signal) indicating the movement of the boom 21 to the control device 200 described later. The stick operating lever 142 can switch between the first stick directional control valve 41 and the second stick directional control valve 38, and outputs an operating signal (electrical signal) indicating the movement of the stick 22 to the control device 200 described later.

[0069] Furthermore, since the explanation of the operating devices has become complicated, the following are omitted from the illustrations: the right-drive operating lever for switching the right-drive directional control valve 36, the bucket operating lever for switching the bucket directional control valve 37, the first attachment operating lever for switching the first attachment directional control valve 42, the left-drive operating lever for switching the left-drive directional control valve 43, the rotation operating lever for switching the rotation directional control valve 44, and the second attachment operating lever for switching the second attachment directional control valve 46.

[0070] The control device 200 controls the hydraulic system 30. The control device 200 is electrically connected to the operating device, which includes the boom operating lever 141 and the stick operating lever 142, and receives operating signals from each of the operating levers 141 and 142. The control device 200 is electrically connected to each of the pressure sensors 121-127 and receives detection signals from each of the pressure sensors 121-123 and 124-127. The control device 200 is electrically connected to each of the IMUs 131-135 and receives detection signals from each of the IMUs 131-135.

[0071] A target surface setting device 151 is electrically connected to the control device 200. The target surface setting device 151 sets the target surface as the object of operation such as excavation by the working device 4. The target surface setting device 151 is, for example, a display device with a touch panel that functions as an input device, and outputs the setting information of the set target surface to the control device 200.

[0072] The control device 200 controls the electromagnetic proportional pressure reducing valve 113a of the pilot circuit 110 according to the operation amount (indication information) of the operating devices 141 and 142, thereby controlling the pump volume of the second hydraulic pump 32 via the second regulator of the second hydraulic pump 32. Similarly, it also controls the pump volume of the first hydraulic pump 31 and the third hydraulic pump 33.

[0073] In addition, the control device 200 controls the hydraulically piloted first boom directional control valve 41 and flow control valve 55 by controlling the electromagnetic proportional pressure reducing valves 113b, 113c and 113d of the pilot circuit 110. The other directional control valves 37 to 40, 42, 44 to 46 and their corresponding flow control valves 51 to 54, 56 to 59 are also controlled in the same way.

[0074] Additionally, the control device 200 controls the hydraulically piloted second CB shut-off valve 62 by controlling the electromagnetic proportional pressure reducing valve 113e of the pilot circuit 110. The other CB shut-off valves 61 and 63 are controlled in the same way.

[0075] Next, use Figures 4-6 The hardware and functional structure of the control device in the engineering machinery of the first embodiment will be described. Figure 4 This is a block diagram illustrating the structure of the hardware and functions of the control device in the engineering machinery according to the first embodiment.

[0076] exist Figure 4In this configuration, the control device 200 is configured to perform area restriction control (control that restricts the operation of the working device 4 to a restricted area). This area restriction control controls the hydraulic actuators 6, 25-27 to ensure that the bucket 23 moves without exceeding the target surface of the work object set for the bucket 23. This area restriction control controls the flow direction of the hydraulic oil supplied to and discharged from each hydraulic actuator 6, 25-27 via directional control valves 36-46, and controls the flow rate (inlet throttling flow rate) of the hydraulic oil supplied to each hydraulic actuator 6, 25-27 via flow control valves 51-59.

[0077] However, in the area restriction control of the working device 4 by the control device 200, when it is necessary to drive any of the hydraulic actuators 6, 25-27 at a low speed, the accuracy of the flow control valves 51-59 may sometimes decrease. For example, in the case of digging operations by the combined action of the boom 21 and the stick 22, when the stick 22 approaches a vertical position, the lifting amount of the boom 21 may become very small. At this time, the inlet throttling flow of the boom cylinder 25 is a small flow, so it is necessary to control the opening of the flow control valve in a small area. However, the control of the opening of the flow control valve has limitations. Figure 5 The error factor shown can sometimes reduce the accuracy of flow control. If the accuracy of flow control valve is reduced, the boom 21 will move up and down and it will be difficult to maintain the accurate operation of the working device 4, and the working device 4 may move out of the restricted area.

[0078] Figure 5 It means Figure 2 The diagram illustrates the structural elements of the hydraulic system of the engineering machinery according to the first embodiment, specifically the factors that reduce the accuracy of flow control in the flow control valve. Flow control of the flow control valve 55 (in one example) will be performed as follows. First, according to the control command from the control device 200, the electromagnetic proportional pressure reducing valve 113d (see reference...) Figure 3 First, a command pressure is generated. Second, the valve core of the flow control valve 55 is displaced according to the command pressure generated by the electromagnetic proportional pressure reducing valve 113d. Finally, the flow rate is controlled according to the amount of opening caused by this displacement in the opening shape formed by the valve core. Figure 5 The upper section of the diagram shows the error range of the generated command pressure relative to the target command pressure (from the control command of the control device 200) of the electromagnetic proportional pressure reducing valve. Figure 5 The mid-section diagram represents the error range of the flow control valve's displacement relative to the generated command pressure of the electromagnetic proportional pressure reducing valve. Figure 5The lower section of the diagram shows the error range of the flow control valve's opening area relative to the valve's displacement (caused by machining errors in the opening shape, etc.). Due to such error factors, the accuracy of flow control can sometimes be reduced when controlling the opening amount of the flow control valve in a small area.

[0079] Therefore, in this embodiment, when performing excavation work through a combined operation involving hydraulic actuators that require low-speed drive, such as the boom 21 and stick 22 described above, the control device 200 sets both the boom cylinder 25 and the stick cylinder 26 to target speeds above a predetermined speed during the movement before and after the stick 22 reaches a vertical position, and operates at these target speeds respectively. This prevents instability in the operation of the working device 4 due to a low inlet throttling flow rate in the boom cylinder 25. In this embodiment, the characteristic feature is that, when the operation of the rotary motor 6 and the bucket cylinder 27 is also considered as the operation target, in order to accurately control the inlet throttling flow rate of the hydraulic actuators 6, 25-27 that are the operation targets, a target speed above a predetermined speed of the hydraulic actuators 6, 25-27 that can maintain the accuracy of flow control is set. In this embodiment, the inlet throttling flow of the hydraulic actuators 6, 25, and 27, which are the objects of operation, is controlled by the flow control valves 51 to 59. Thus, even when the inlet throttling flow is small, the stable operation of the working device 4 can be maintained.

[0080] The control device 200 is, for example, a microcomputer comprising a storage device 201 consisting of RAM, ROM, etc., and a processing device 202 consisting of a CPU, MPU, etc. The storage device 201 stores pre-installed programs and various information required for controlling the actuation of multiple hydraulic actuators 6, 25-27, multiple directional control valves 36-46, multiple flow control valves 51-59, and multiple hydraulic pumps 31-33. The processing device 202 performs various functions by appropriately reading the programs and various information from the storage device 201 and executing processing according to the programs. Furthermore, the control device 200 can be composed of a single computer or multiple computers.

[0081] The control device 200, as a functional unit capable of preventing the reduction of control accuracy of the inlet throttling flow rate during low-speed driving of hydraulic actuators 6, 25-27, includes an actuator target speed calculation unit 211, an actuator target flow rate calculation unit 212, a pump target flow rate calculation unit 213, a pump control command calculation unit 214, a flow control valve target opening calculation unit 215, a flow control valve control command calculation unit 216, an actuator final target flow rate calculation unit 217, an actuator speed limit calculation unit 218, a directional control valve target opening calculation unit 219, a directional control valve control command calculation unit 220, a CB shut-off valve target opening calculation unit 221, and a CB shut-off valve control command calculation unit 222.

[0082] The actuator target speed calculation unit 211 calculates the speeds of the hydraulic actuators 6, 25, and 27 that correspond to the actions of the rotating body 3 (machine body) and the working device 4 under specified conditions, based on the detection information from the posture detection devices 131-135, the target surface setting information from the target surface setting device 151, and the operation signals (indication information) from the operating levers 141 and 142 of the operating device, and sets these speeds as temporary target speeds. For example, it calculates the target speed of the tips of the bucket 23 teeth that prevents the tips of the bucket 23 from leaving the target surface, and calculates the target speeds of the hydraulic actuators required to achieve the calculated tip target speed. Furthermore, it determines whether the temporary target speeds of the hydraulic actuators 6, 25, and 27 are less than the limit speed Va_lim of the hydraulic actuators 6, 25, and 27, which is the result of the calculation by the actuator limit speed calculation unit 218 (described later). If the temporary target speed is higher than or equal to the limit speed, the temporary target speed is set as the target speed of the hydraulic actuators 6, 25, and 27. On the other hand, if the temporarily set target speed is less than the limit speed, the target speed of each hydraulic actuator 6, 25 to 27 is recalculated using the limit speed of the hydraulic actuators 6, 25 to 27. The calculated target speed Va_t of each hydraulic actuator 6, 25 to 27 is output to the actuator target flow calculation unit 212.

[0083] The actuator target flow calculation unit 212 calculates the target flow rate Qa_t to be supplied to each hydraulic actuator 6, 25-27 based on the target speed Va_t of each hydraulic actuator 6, 25-27 calculated by the actuator target speed calculation unit 211 and the design specifications of each hydraulic actuator 6, 25-27 pre-stored in the storage device 201. The calculated target flow rate Qa_t of each hydraulic actuator 6, 25-27 is then output to the pump target flow calculation unit 213 and the flow control valve target opening calculation unit 215.

[0084] The pump target flow calculation unit 213 calculates the flow rate of hydraulic oil to be discharged by hydraulic pumps 31-33 as the pump target flow rate Qp_t based on the target flow rate Qa_t of each hydraulic actuator 6, 25-27, which is the result of the calculation of the actuator target flow rate calculation unit 212. The pump target flow rate Qp_t is then output to the pump control command calculation unit 214.

[0085] The pump control command calculation unit 214 calculates the pump flow command based on the calculation result of the pump target flow calculation unit 213, i.e., the pump target flow Qp_t, generates an electrical signal corresponding to the pump flow command, and outputs it to the pump electromagnetic proportional pressure reducing valve 113a.

[0086] The flow control valve target opening calculation unit 215 calculates the final target opening Af_Ft of each flow control valve 51-59 to ensure the accuracy of flow control based on the target flow rate Qa_t of each hydraulic actuator 6, 25-27 (which is the result of the calculation by the actuator target flow calculation unit 212), the detection value of the pressure sensor 121-127 that can detect the differential pressure before and after the corresponding flow control valve 51-59, and the limit opening area Af_lim (which is the set value). The final target opening Af_Ft of each flow control valve 51-59 calculated by the calculation unit is output to the actuator final target flow calculation unit 217. If the temporary target speed or the target speed of each hydraulic actuator 6, 25-27 in the actuator target speed calculation unit 211 is higher than or equal to the limit speed Va_lim of the hydraulic actuator 6, 25-27 (described later), the unit outputs the result to the flow control valve control command calculation unit 216.

[0087] Specifically, the calculation of the target opening calculation unit 215 of the flow control valve is performed by... Figure 6 The process shown is performed. Figure 6 It means Figure 4 The diagram shows a block diagram of the subdivision processing function of the flow control valve target opening calculation unit in the control device of the engineering machinery according to the first embodiment.

[0088] The flow control valve target opening calculation unit 215 calculates the target opening area of ​​each flow control valve 51-59 through processing by a differential processing unit 215a, a square root processing unit 215b, a coefficient processing unit 215c, and a division processing unit 215d based on the flow calculation formula of the throttle orifice. The differential processing unit 215a performs differential processing by subtracting the detected values ​​Ppm (discharge pressure of each hydraulic pump 31-33) from the detected values ​​Pmi (inlet throttle pressure of each hydraulic actuator 6, 25-27) of each pressure sensor 124, 125, 126, 127. That is, the differential processing unit 215a is equivalent to calculating the pressure difference ΔP (differential pressure between upstream and downstream) between the upstream and downstream pressures of each flow control valve 51-59. The square root processing unit 215b performs the process of taking the square root of the differential pressure ΔP across each flow control valve 51-59, which is the result of the processing unit 215a. The coefficient processing unit 215c executes the processing result of the square root processing unit 215b. The process involves multiplying by a coefficient α. Coefficient α is the value of all constants, including the flow coefficient in the flow calculation formula for the orifice and the density of the working fluid. The division processing unit 215d processes the target flow rate Qa_t of each hydraulic actuator 6, 25-27, which is the result of the calculation by the actuator target flow calculation unit 212, by dividing it by the result of the coefficient processing unit 215c. Through this series of processes—differential processing unit 215a, square root processing unit 215b, coefficient processing unit 215c, and division processing unit 215d—the target opening area Af_t of each flow control valve 51-59 using the orifice flow calculation formula is calculated.

[0089] The flow control valve target opening calculation unit 215 further includes a maximum value selection processing unit 215e, which selects the maximum value between the target opening area Af_t of each flow control valve 51-59 calculated by a series of processing units 215a, 215b, 215c, and 215d and the maximum value between the limit opening area Af_lim stored in the storage device 201. The maximum value selection processing unit 215e outputs the maximum value between the target opening area Af_t of each flow control valve 51-59 and the limit opening area Af_lim of the set value as the final target opening area Af_Ft of each flow control valve 51-59 to the actuator final target flow calculation unit 217.

[0090] The limiting opening area Af_lim is the minimum opening area at which the flow control accuracy of each flow control valve 51-59 can maintain the allowable accuracy. The limiting opening area Af_lim is determined as follows: In the area restriction control of the working device 4, an allowable error is preset for the control of the tip position of the bucket 23. The allowable error of the drive speed of each hydraulic actuator 6, 25-27 can be specified corresponding to the allowable error of the bucket 23's position. The allowable error of the inlet throttling flow rate of each hydraulic actuator 6, 25-27 can be specified corresponding to the allowable error of the drive speed of each hydraulic actuator 6, 25-27. According to... Figure 5 The error shown is set as the minimum value of the opening area of ​​each flow control valve 51 to 59 that can achieve the allowable error of the inlet throttling flow of each hydraulic actuator 6, 25 to 27.

[0091] The flow control valve control command calculation unit 216 calculates the flow control valve command corresponding to the final target opening amount Af_Ft of each flow control valve 51 to 59, which is the result of the calculation of the flow control valve target opening calculation unit 215, generates an electrical signal corresponding to the flow control valve command, and outputs it to each electromagnetic proportional pressure reducing valve 113d used for the flow control valve.

[0092] The actuator final target flow calculation unit 217 calculates the final target opening amount Af_Ft of each flow control valve 51-59 based on the calculation result of the flow control valve target opening calculation unit 215 and the detection value of the pressure sensors 121-127 that can detect the differential pressure before and after each flow control valve 51-59, and calculates the final target flow rate Qa_Ft of each hydraulic actuator 6, 25-27. This calculation uses, for example, the flow calculation formula of the throttle orifice and a pre-set mapping. The calculated final target flow rate Qa_Ft of each hydraulic actuator 6, 25-27 is output to the actuator speed limiting calculation unit 218.

[0093] The actuator limiting speed calculation unit 218 calculates the speed of each hydraulic actuator 6, 25, 27 corresponding to the final target flow rate Qa_Ft of the hydraulic actuators 6, 25, 27, which is the result of the calculation by the actuator final target flow rate calculation unit 217, and uses it as the limiting speed Va_lim. The calculated limiting speed Va_lim of the hydraulic actuators 6, 25, 27 is output to the actuator target speed calculation unit 211.

[0094] The directional control valve target opening calculation unit 219 calculates the target opening amount Ad_t of each directional control valve 36-46 based on the thrust or pressure information of each hydraulic actuator 6, 25-27 obtained from the detection values ​​of the inlet and outlet throttling pressures of each hydraulic actuator 6, 25-27, and the operation amount (indication information) of each operating lever 141, 142 of the operating device. The target opening amount is, for example, the target amount of the outlet throttling opening, which is either the inlet throttling opening or the outlet throttling opening. This opening calculation uses, for example, a mapping pre-stored in the storage device 201. The calculated target opening amount Ad_t of each directional control valve 36-46 is output to the directional control valve control command calculation unit 220.

[0095] The directional control valve control command calculation unit 220 calculates the result of the calculation of the directional control valve target opening calculation unit 219, which is the directional control valve command corresponding to the target opening amount Ad_t of each directional control valve 36~46. The directional control valve command is generated and output to each electromagnetic proportional pressure reducing valve 113b, 113c used for the directional control valve.

[0096] The CB shut-off valve target opening calculation unit 221 calculates the target opening amount Ac_t of each CB shut-off valve 61 to CB shut-off valve 63 based on the operation amount (indication information) of each operating lever 141, 142 of the operating device. This calculation uses, for example, a mapping pre-stored in the storage device 201. The calculated target opening amount Ac_t of each CB shut-off valve 61 to 63 is output to the CB shut-off valve control command calculation unit 222.

[0097] The CB shut-off valve control command calculation unit 222 calculates the result of the calculation of the CB shut-off valve target opening calculation unit 221, which is the CB shut-off valve command corresponding to the target opening amount Ac_t of each CB shut-off valve 61~63, generates an electrical signal corresponding to the CB shut-off valve command, and outputs it to each electromagnetic proportional pressure reducing valve 113e used for the CB shut-off valve.

[0098] Next, use Figure 7 The control sequence of the hydraulic system of the control device for the engineering machinery of the first embodiment will be explained. Figure 7 It means Figure 4 A flowchart illustrating an example of the control sequence of the control device for the engineering machinery of the first embodiment.

[0099] exist Figure 7 middle, Figure 4The control device 200 first determines whether there is an input of an operation signal from the operating devices 141 and 142 (step S10). In step S10, if it is determined that there is no input of an operation signal (No), the calculation process related to the control of the hydraulic pumps 31-33, directional control valves 36-46, flow control valves 51-59, and CB shut-off valves 61-63 ends. On the other hand, if it is determined that there is an input of an operation signal (Yes), steps S20 and S30 are performed.

[0100] In step S20, the control device 200 calculates the target opening amount Ad_t (e.g., outlet throttling opening) of each directional control valve 36-46 based on the load pressure or thrust information of each hydraulic actuator 6, 25-27 obtained from the detection values ​​of pressure sensors 124-127 and the operation amount (indication information) of the operating devices 141, 142. Furthermore, it calculates the target opening amount Ac_t of each CB shut-off valve 61-CB shut-off valve 63 based on the operation amount (indication information) of the operating devices 141, 142.

[0101] In addition, in parallel with step S20, the control device 200 performs the target speed Va_t of each hydraulic actuator 6, 25-27 corresponding to the operation of the operation device 141, 142 based on the detection signals of the posture detection devices 131-135, the target surface setting information of the target surface setting device 151, the operation signals (indication information) of each operating lever 141, 142 of the operation device, the calculation of the rotating body 3 (machine body) and the working device 4 under the specified conditions (step S30).

[0102] Next, the control device 200 calculates the target flow rate Qa_t of each hydraulic actuator 6, 25-27 based on the target speed Va_t of each hydraulic actuator 6, 25-27 as the calculation result of step S30 (step S40). Furthermore, based on the target flow rate Qa_t of each hydraulic actuator 6, 25-27 as the calculation result of step S40, the target flow rate Qp_t of hydraulic pumps 31-33 is calculated, and based on the target flow rate Qa_t of each hydraulic actuator 6, 25-27 as the calculation result of step S40, the detection value of pressure sensors 121-127, and the limit opening area Af_lim of the set value, the final target opening Af_Ft of each flow control valve 51-59 is calculated (step S50).

[0103] Next, the control device 200 calculates the final target flow rate Qa_Ft of each flow control valve 51-59 based on the final target opening Af_Ft of each flow control valve 51-59 (the result of step S50) and the detection values ​​of pressure sensors 121-127 (step S60). Then, the speed of each hydraulic actuator 6, 25-27 corresponding to the final target flow rate Qa_Ft of each hydraulic actuator 6, 25-27 (the result of step S60) is calculated as the limiting speed Va_lim (step S70).

[0104] Next, the control device 200 determines whether the target speed Va_t of each hydraulic actuator 6, 25-27, as the result of the calculation in step S30, is less than the limit speed Va_lim of each hydraulic actuator 6, 25-27, as the result of the calculation in step S70 (Va_t < Va_lim) (step S80). In step S80, if the determination is "yes", the process proceeds to step S90, and steps S40-S80 are repeated again. On the other hand, if the determination is "no", the process proceeds to step S100, ending the series of processes.

[0105] In step S80, if it is determined that the target speed Va_t is less than the limit speed Va_li (yes), the calculation result of step S30 is discarded, and the calculation result of step S70, i.e., the limit speed Va_lim of hydraulic actuators 6, 25~27, is used to recalculate the target speed Va_t of each hydraulic actuator 6, 25~27 (step S90). The recalculation of the target speed Va_t of each hydraulic actuator 6, 25~27 is based on the limit speed Va_lim of the hydraulic actuator corresponding to the flow control valve whose limit opening area Af_lim is selected as the final target opening Af_Ft, and the remaining target speed Va_t of the hydraulic actuators required for performing the area restriction control is recalculated.

[0106] In step S90, the target speed Va_t of each hydraulic actuator 6, 25-27 is recalculated using the limited speed Va_lim of the hydraulic actuators 6, 25-27. Then, the target speed Va_t of each hydraulic actuator 6, 25-27 is used to recalculate the process in steps S40-S80. Therefore, the target pump flow rate Qp_t of hydraulic pumps 31-33, taking into account the limited speed Va_lim of the hydraulic actuators 6, 25-27, and the final target opening Af_Ft of each flow control valve 51-59 are recalculated (step S50).

[0107] On the other hand, if in step S80 it is determined that the target speed Va_t is above the limit speed Va_li (no), the pump flow command is calculated based on the calculation result or recalculation result of step S50, i.e., the target pump flow rate Qp_t, and the command signal is output to the pump electromagnetic proportional pressure reducing valve 113a. Furthermore, based on the calculation result or recalculation result of step S50, i.e., the final target opening Af_Ft of each flow control valve 51-59, the flow control valve command is calculated and the command signal is output to the flow control valve electromagnetic proportional pressure reducing valve 113d (step S100). Additionally, based on the calculation result of step S20, i.e., the target opening Ad_t of each directional control valve 36-46, the directional control valve command is calculated and the command signal is output to the directional control valve electromagnetic proportional pressure reducing valves 113b and 113c. Furthermore, based on the target opening Ac_t of each CB shut-off valve 61-63, the CB shut-off valve command is calculated and the command signal is output to the CB shut-off valve electromagnetic proportional pressure reducing valve 113e (step S100).

[0108] Next, use Figures 2-4 as well as Figures 6-8 The operation and effects of the engineering machinery according to the first embodiment are explained. Figure 8 This is an explanatory diagram showing the operation and effects of the engineering machinery according to the first embodiment.

[0109] To simplify the explanation here, for the purpose of proceeding... Figure 8 The following explanation uses the control action of limiting the area of ​​movement of the front end of the bucket 23 by the combined action of the boom 21 and stick 22 as an example. Figure 8 In the middle, the tip of the bucket 23 is moved towards the machine body 2 and 3 relative to the target surface St shown by the double-dotted line. Figure 4 The control device 200 shown performs area restriction control to control the movement of the boom 21 and stick 22 in a manner that prevents the tips of the bucket 23 from disengaging from the target surface St. In this case, as the stick 22 approaches a vertical position, the amount of rise of the boom 21 gradually decreases.

[0110] Specifically, the control device 200 (211) calculates the target speed Vt_t (1) of the bucket 23's tooth tip, ensuring it does not detach from the target surface St, based on the operation signals from the operation devices 141 and 142, the detection values ​​from the posture detection devices 131-135, and the target surface setting information from the target surface setting device 151. Furthermore, it calculates the target speed Vbm_t (1) of the boom cylinder 25 and the target speed Vam_t (1) of the stick cylinder 26 required to achieve the calculated tooth tip target speed Vt_t (1). Figure 7 The step S30 shown). The target speed of these calculation results ( Figure 8 The thick arrow in the dashed line (in the middle) is a temporary setting.

[0111] When the boom 22 is in a near-vertical position and the lifting amount of the boom 21 is small, Figure 6 In the operation of the control device 200 (215) shown, sometimes the target opening area Af_t of the flow control valves 53, 54, and 58 used for the boom cylinder 25, calculated based on the target flow rate obtained from the target speed Vbm_t of the boom cylinder 25, is smaller than the limiting opening area Af_lim that ensures the accuracy of flow control. In this case, the control device 200 (215) selects the limiting opening area Af_lim as the final target opening area Af_Ft of the flow control valves 53, 54, and 58. This ensures the accuracy of the flow control valves 53, 54, and 58 in controlling the flow of the boom cylinder 25.

[0112] Figure 4 The control device 200 (217, 218) shown uses the final target opening area Af_Ft, i.e. the limit opening area Af_lim, of the flow control valves 53, 54, 58 used for the boom cylinder 25 and the detection values ​​of pressure sensors 121~124 (the differential pressure before and after the flow control valves 53, 54, 58) to calculate the limiting speed Vbm_lim of the boom cylinder 25.

[0113] The control device 200 (211) uses the limit speed Vbm_lim of the boom cylinder 25 as a reference, and recalculates the target speed Vt_t(2) of the bucket 23 tooth tip while maintaining the direction of the target speed Vt_t(1) of the previous calculation result. Furthermore, it recalculates the target speed Vbm_t(2) of the boom cylinder 25 and the target speed Vam_t(2) of the stick cylinder 26 required for the recalculated target speed Vt_t(2). In this case, the target speed Vbm_t(2) of the boom cylinder 25 is the limit speed Vbm_lim of the boom cylinder 25. Figure 8 In the recalculation, the target speed is represented by a thick arrow on a solid line. In addition, the control device 200 (215) recalculates the target opening area Af_t of the flow control valves 52 and 55 used by the boom cylinder 26 corresponding to the target speed Vam_t (2) of the boom cylinder 26 in the recalculation result.

[0114] Thus, in this embodiment, when the area restriction control of the working device 4 is in effect, if the target speed of any one of the multiple hydraulic actuators is lower than the limit speed, the target speed of each hydraulic actuator is recalculated to maintain the moving direction of the bucket 23 corresponding to the operation of the operating devices 141 and 142 and to ensure the accuracy of the flow control of each flow control valve 51 to 59. Therefore, since the accuracy of the flow control of the hydraulic actuators by each flow control valve 51 to 59 can be ensured, the movement of the bucket 23 can be accurately controlled.

[0115] As described above, the hydraulic excavator 1 (construction machinery) of the first embodiment includes: a working device 4, which includes a bucket 23 as a working tool; a boom cylinder 25, a stick cylinder 26, and a bucket cylinder 27 (at least one hydraulic actuator) for driving the working device 4; flow control valves 51 to 59 as hydraulic devices capable of adjusting the flow rate of hydraulic oil supplied to the hydraulic actuators 25 to 27; a control device 200 that controls the hydraulic actuators 25 to 27 via the flow control valves 51 to 59 (hydraulic devices) to satisfy the condition that the bucket 23 (working tool) does not exceed the target surface set as the working object of the bucket 23 (working tool); and an IMU 131 to 135 as a posture detection device for detecting the posture of the working device 4. Based on the detection information from IMUs 131-135 (attitude detection devices) and the target surface setting information, the control device 200 calculates the speed of the hydraulic actuators 25-27 that makes the bucket 23 (working tool) meet the above conditions, using this speed as the target speed Va_t. It then calculates the target value of the flow control valves 51-59 (hydraulic equipment) corresponding to the calculated target speed Va_t of the hydraulic actuators 25-27. The calculated target value of the flow control valves 51-59 (hydraulic equipment) is less than the allowable accuracy of flow control by the flow control valves 51-59 (hydraulic equipment). Under the condition of the limit value, the speed of hydraulic actuators 25~27 obtained based on the lower limit value is used as the limit speed Va_lim of hydraulic actuators 25~27. Based on the calculated limit speed Va_lim of hydraulic actuators, the target speed Va_t of hydraulic actuators 25~27 that makes bucket 23 (working tool) meet the conditions is recalculated. Corresponding to the recalculated target speed Va_t of hydraulic actuators 25~27, the target value of flow control valves 51~59 (hydraulic equipment) is used as the control target to control flow control valves 51~59 (hydraulic equipment).

[0116] According to this structure, when the target value of the flow control valves 51-59 (hydraulic equipment) used to control the flow rate supplied to the hydraulic actuators 25-27 is lower than the lower limit value that can ensure the accuracy of flow control, the target value of the flow control valves 51-59 (hydraulic equipment) corresponding to the target speed Va_t of the hydraulic actuators 25-27 calculated based on the limit speed Va_lim of the hydraulic actuators 25-27 calculated using the lower limit value is used as the control target. Therefore, even when the working device 4 is operated by low-speed drive of the hydraulic actuators 25-27 in the area restriction control of the working device 4, the accuracy of flow control of the hydraulic actuators 25-27 can be prevented from decreasing, thereby enabling accurate control of the operation of the working device 4.

[0117] In this embodiment, at least one hydraulic actuator driving the working device 4 is composed of multiple hydraulic actuators such as boom cylinder 25, stick cylinder 26, and bucket cylinder 27. The target speed calculation of the hydraulic actuators 25-27 in the control device 200 is based not only on the detection information from IMUs 131-135 (posture detection devices) and the target surface setting information, but also on the movement direction of the bucket 23 (working tool) obtained from the instruction information instructing the operation of the working device 4. Furthermore, the recalculation of the target speed of the hydraulic actuators 25-27 in the control device 200 is based on the calculated limit speed, calculating the speed of the multiple hydraulic actuators 25-27 that maintain the movement direction of the bucket 23 (working tool) and satisfy the condition.

[0118] According to this structure, the target speed of multiple hydraulic actuators 25-27 is recalculated so that the bucket 23 (working tool) moves in a direction corresponding to the instruction information of the automatic control of the operating device 200 based on the operating devices 141, 142. Therefore, the working device 4 can be operated according to the instructions of the automatic control of the operating devices 141, 142 and the control device 200.

[0119] In this embodiment, the hydraulic equipment includes flow control valves 51-59 capable of controlling the flow rate of hydraulic oil supplied to hydraulic actuators 25-27, and pressure sensors 121-126 serving as pressure detection devices for detecting the differential pressure across flow control valves 51-59. The target value of the hydraulic equipment is the target opening area Af_t of the flow control valves 51-59 calculated based on the target flow rate Qa_t of the hydraulic actuators 25-27 obtained from the calculated target speed Va_t, and the detection value from the pressure sensors 121-126 (pressure detection devices). The lower limit value is a predetermined limit opening area Af_lim for the flow control valves 51-59 based on the accuracy of their flow control. The calculation of the limit speed Va_lim of the hydraulic actuators 25-27 in the control device 200 is based on the flow rate calculated using the limit opening area Af_lim of the flow control valves 51-59 and the detection value from the pressure sensors 121-126 (pressure detection devices).

[0120] According to this structure, in the action restriction control of the working device 4, the action of the working device 4 can be accurately controlled by controlling the flow of the hydraulic actuators 25-27 through the flow control valves 51-59.

[0121] Furthermore, the hydraulic excavator 1 (construction machinery) of this embodiment includes directional control valves 37-42, 45, and 46, which can control the flow direction of hydraulic oil supplied to hydraulic actuators 25-27 and the flow of hydraulic oil discharged from hydraulic actuators 25-27. Flow control valves 51-59 are disposed upstream of directional control valves 37-42, 45, and 46. The pressure detection device includes pressure sensors 124-126 that detect the inlet throttling pressure and outlet throttling pressure of hydraulic actuators 25-27. The control device 200 controls the outlet throttling opening of directional control valves 37-42, 45, and 46 based on the thrust or pressure information of hydraulic actuators 25-27 obtained from the detection values ​​of pressure sensors 124-126.

[0122] According to this structure, in the action restriction control of the working device 4, by controlling the outlet throttling opening of the directional control valves 37~42, 45, 46, the hydraulic actuators 25~27 can be prevented from disengaging due to the weight of the working device 4.

[0123] [Second Implementation]

[0124] Next, use Figures 9-12 The engineering machinery according to the second embodiment of the present invention will be described. Furthermore, in Figures 9-12 In, with Figures 1-8 The parts of the accompanying drawings with the same reference numerals are identical, therefore their detailed descriptions are omitted. Figure 9 This is a block diagram illustrating the structure of the hardware and functions of the control device in the engineering machinery according to the second embodiment. Figure 10 This is a diagram showing the factors (error factors) that reduce the accuracy of flow control in the hydraulic pump, a structural element of the hydraulic system of the engineering machinery in the second embodiment.

[0125] The difference between the engineering machinery in the second embodiment and the first embodiment lies in that, in the area restriction control performed by the control device, the accuracy of flow control for each hydraulic actuator is ensured not by limiting the lower limit of the opening of the flow control valve, but by limiting the lower limit of the pump flow rate. That is, Figure 9 In the control device 200A of the engineering machinery shown in the second embodiment, the processing contents of the pump target flow calculation unit 213A, the flow control valve target opening calculation unit 215A, and the actuator speed limit calculation unit 218A are different from the functional units 213, 215, and 218 of the control device 200 of the first embodiment, and the actuator final target flow calculation unit 217 of the control device 200 of the first embodiment is not required. The structure of the second embodiment is the same as that of the first embodiment, except for these differences, and its description is omitted.

[0126] In the area restriction control of the control device 200A, for example, when it is necessary to drive any one of the hydraulic actuators 6, 25-27 at a low speed individually, the discharge flow rate of the hydraulic pumps 31-33 may sometimes be small. In this case, it is necessary to control the discharge flow rate of the hydraulic pumps 31-33 by a small amount. However, the control of the discharge flow rate of the hydraulic pumps 31-33 has the following limitations: Figure 10 The error factor shown sometimes reduces the accuracy of flow control for hydraulic actuators 6, 25-27. If the accuracy of flow control decreases, it becomes difficult to maintain the correct operation of the working device 4, and there is a possibility that the working device 4 may move outside the restricted area.

[0127] Hydraulic pump 32 (reference) Figure 2 The discharge flow rate of the electromagnetic proportional pressure reducing valve 113a (refer to...) is controlled as follows. First, according to the control command from the control device 200A, the electromagnetic proportional pressure reducing valve 113a (refer to...)... Figure 3 First, the command pressure is generated by the electromagnetic proportional pressure reducing valve 113a. Second, the command pressure generated by the electromagnetic proportional pressure reducing valve 113a is input to the command pressure port 32a of the regulator of the hydraulic pump 32 (refer to...). Figure 2 When the tilt of the inclined plate or inclined shaft of the hydraulic pump 32 changes, the discharge flow rate is controlled according to the tilt of the hydraulic pump 32. Figure 10 The above figure shows the error range of the generated command pressure relative to the target command pressure (from the control command of the control device) of the electromagnetic proportional pressure reducing valve. Figure 10 The figure below shows the error range of the hydraulic pump's discharge flow rate relative to the command pressure generated by the electromagnetic proportional pressure reducing valve (due to manufacturing errors, etc.). Because of such error factors, the accuracy of flow control can sometimes be reduced when controlling the hydraulic pump's discharge flow rate by small amounts.

[0128] Therefore, the pump target flow calculation unit 213A of the control device 200A in the second embodiment calculates the flow rate that the hydraulic pumps 31-33 should eject as the final target flow rate Qp_Ft, based on the limit flow rate Qp_lim (set value) and the target flow rate Qa_t of each hydraulic actuator 6, 25-27 (calculated by the actuator target flow rate calculation unit 212). The calculated final target flow rate Qp_Ft is then output to the pump control command calculation unit 214 and the actuator speed limit calculation unit 218A.

[0129] Specifically, the calculation of the pump target flow calculation unit 213A is performed by... Figure 11 The process shown is performed. Figure 11 It means Figure 9 A block diagram showing the subdivision processing function of the pump target flow calculation unit in the control device of the engineering machinery of the second embodiment.

[0130] The pump target flow calculation unit 213A includes a pump target flow calculation processing unit 213b and a maximum value selection processing unit 213c. The pump target flow calculation processing unit 213b calculates the target flow rate Qp_t of hydraulic pumps 31-33 by adding the calculation results of the actuator target flow calculation unit 212 (i.e., the target flow rates Qa_t of each hydraulic actuator 6, 25-27). The maximum value selection processing unit 213c selects the maximum value between the processing result of the pump target flow calculation processing unit 213b (i.e., the target flow rate Qp_t of hydraulic pumps 31-33) and the pre-stored limit flow rate Qp_lim in the storage device 201. The maximum value selection processing unit 213c outputs the maximum value between the calculated target flow rate Qp_t of hydraulic pumps 31-33 and the set limit flow rate Qp_lim as the final target flow rate Qp_Ft of hydraulic pumps 31-33 to the pump control command calculation unit 214 and the actuator speed limit calculation unit 218A.

[0131] The limiting flow rate Qp_t is equivalent to the minimum discharge flow rate at which the accuracy of flow control for each hydraulic actuator 6, 25-27 can be maintained within permissible limits. The limiting flow rate Qp_t is determined, for example, as follows: In the area restriction control of the working device 4, a permissible error is preset for the control of the tip position of the bucket 23. A permissible error for the drive speed of each hydraulic actuator 6, 25-27 is specified corresponding to the permissible error for the position of the bucket 23. A permissible error for the inlet throttling flow rate of each hydraulic actuator 6, 25-27 is specified corresponding to the permissible error for the drive speed of each hydraulic actuator 6, 25-27. The minimum discharge flow rate of the hydraulic pumps 31-33 that achieves the permissible error for the inlet throttling flow rate of each hydraulic actuator 6, 25-27 is set as the limiting flow rate.

[0132] The speeds of hydraulic actuators 6, 25, and 27, corresponding to the final target flow rate Qp_Ft of hydraulic pumps 31 to 33, calculated by actuator speed limit calculation unit 218A and pump target flow calculation unit 213A, are used as the speed limit Va_lim of hydraulic actuators 6, 25, and 27. The calculated speed limit Va_lim of hydraulic actuators 6, 25, and 27 is then output to actuator target speed calculation unit 211.

[0133] The flow control valve target opening calculation unit 215A calculates the target opening amount Af_t of each flow control valve 51 to flow control valve 59 based on the operation amount (indication information) of each operating lever 141, 142 of the operating device. This calculation, for example, uses a mapping pre-stored in the storage device 201. The calculated target opening amount Af_t of each flow control valve 51 to 59 is output to the flow control valve control command calculation unit 216.

[0134] Next, use Figure 12The control sequence of the hydraulic system of the control device for the engineering machinery in the second embodiment will be explained. Figure 12 It means Figure 9 A flowchart illustrating an example of the control sequence of the control device for the engineering machinery according to the second embodiment is shown.

[0135] Figure 12 The control sequence of the control device in the second embodiment shown is the same as the control sequence of the control device in the first embodiment (refer to...). Figure 7 The difference lies in the processing content of steps S20A and S50A, which calculate the final target flow rate Qp_Ft of the pump and the target opening Af_t of each flow control valve 51-59, and the processing content of step S70A, which calculates the limiting speed Va_lim of the hydraulic actuators 6, 25-27. Furthermore, step S60 of the first embodiment is unnecessary. The processing of the other steps in the second embodiment is the same as that in the first embodiment, and its description is omitted.

[0136] exist Figure 12 middle, Figure 9 If the control device 200A determines in step S10 that there is an input of an operation signal (Yes), it proceeds to steps S20A and S30. In step S20A, the control device 200A calculates the target opening amount Ad_t of each directional control valve 36-46 and the target opening amount Ac_t of each CB shut-off valve 61-63, similar to the first embodiment. However, unlike the first embodiment, the target opening amount Af_t of each flow control valve 51-59 is calculated based on the operation amount (indication information) of the operation devices 141 and 142.

[0137] In step S50A, the control device 200A calculates the maximum value between the target flow rate Qa_t of each hydraulic actuator 6, 25-27 and the set limit flow rate Qp_lim, which is the result of the calculation in step S40, and uses it as the final target flow rate Qp_Ft of the hydraulic pumps 31-33. Next, the speed of each hydraulic actuator 6, 25-27 corresponding to the final target flow rate Qp_Ft of the hydraulic pumps 31-33, which is the result of the calculation in step S50A, is calculated as the limiting speed Va_lim (step S70A).

[0138] Next, the control device 200A determines whether the calculation result of step S30, i.e. the target speed Va_t of each hydraulic actuator 6, 25~27, is less than the calculation result of step S70A, i.e. the limit speed Va_lim of each hydraulic actuator 6, 25~27 (Va_t < Va_lim) (step S80).

[0139] In step S80, if it is determined that the target speed Va_t is less than the limit speed Va_li (yes), the calculation result of step S30 is discarded, and the calculation result of step S70A, i.e., the limit speed Va_lim of hydraulic actuators 6, 25~27, is used to recalculate the target speed Va_t of each hydraulic actuator 6, 25~27 (step S90). The recalculation of the target speed Va_t of each hydraulic actuator 6, 25~27 is based on the limit speed Va_lim of the hydraulic actuator when the limit flow rate Qp_lim is selected as the final target flow rate Qp_Ft of the pump, and the target speed Va_lim of each hydraulic actuator required for the execution of the area restriction control is recalculated.

[0140] In step S90, the target speed Va_t of each hydraulic actuator 6, 25-27 is recalculated using the limited speed Va_lim of the hydraulic actuators 6, 25-27. Then, steps S40, S50A, S70A, and S80 are repeated using the recalculated target speed Va_t of each hydraulic actuator 6, 25-27. Thus, the final target flow rate Qp_Ft of the hydraulic pumps 31-33, taking into account the limited speed Va_lim of the hydraulic actuators 6, 25-27, is recalculated.

[0141] Thus, in this embodiment, when the area restriction control of the working device 4 is performed, the final target flow rate Qp_Ft of the hydraulic pumps 31-33 is set to a limit flow rate Qp_lim or higher that ensures control accuracy. Therefore, by controlling the flow of the hydraulic actuators 25-27 through the hydraulic pumps 31-33, the accuracy of the flow control of the hydraulic actuators 25-27 can be ensured.

[0142] When the target speed Va_t of the hydraulic actuators 25-27 is lower than the limit speed Va_lim, the target speed Va_t of the hydraulic actuators 25-27 is recalculated to maintain the moving direction of the bucket 23 corresponding to the operation of the operating devices 141, 142 and to ensure the accuracy of the flow control of the hydraulic pumps 31-33. This ensures the accuracy of the flow control of the hydraulic pumps 31-33 on the hydraulic actuators 25-27, thus enabling accurate control of the movement of the bucket 23.

[0143] In the second embodiment described above, when the target value of the hydraulic pumps 31-33 used to control the flow rate supplied to the hydraulic actuators 25-27 is lower than the lower limit value that can ensure the accuracy of flow control, the target value of the hydraulic pumps 31-33 (hydraulic equipment) corresponding to the target speed Va_t of the hydraulic actuators 25-27 calculated based on the limit speed Va_lim of the hydraulic actuators 25-27 calculated using the lower limit value is used as the control target. Therefore, even when the working device 4 is operated by low-speed drive of the hydraulic actuators 25-27 in the area restriction control of the working device 4, the accuracy of flow control of the hydraulic actuators 25-27 can be prevented from decreasing, and the operation of the working device 4 can be accurately controlled.

[0144] In this embodiment, the hydraulic equipment consists of hydraulic pumps 31-33 that supply hydraulic oil to hydraulic actuators 25-27. The target value of the hydraulic equipment is the target flow rate of hydraulic pumps 31-33 calculated based on the target flow rate of the hydraulic actuators 25-27 obtained from the calculated target speed. The aforementioned lower limit value is a preset limit flow rate for hydraulic pumps 31-33 based on the accuracy of flow control of hydraulic pumps 31-33. The calculation of the speed limit of hydraulic actuators 25-27 in the control device 200A is based on the limit flow rate of hydraulic pumps 31-33.

[0145] According to this structure, in the motion restriction control of the working device 4, the motion of the working device 4 can be accurately controlled by the flow control of the hydraulic actuators 25-27 by the hydraulic pumps 31-33.

[0146] [Other Implementation Methods]

[0147] Furthermore, the present invention is not limited to the first embodiment described above, and includes various modifications. The embodiments described above are detailed for the purpose of easily understanding and illustrating the present invention, and are not limited to having all the structures described. For a part of the structure of this embodiment, other structures can be added, deleted, or replaced.

[0148] For example, in the first and second embodiments described above, examples are shown where control devices 200 and 200A control the openings of directional control valves 37-42, 44-46 and flow control valves 51-59, as well as the flow rate of hydraulic pumps 31-33, based on the instruction information of the operation of the operating levers 141 and 142, which are operating devices for indicative of the movement of the rotating body 3 and the working devices 21, 22, and 23. However, control devices 200 and 200A may also be configured to control the openings of directional control valves 37-42, 44-46 and flow control valves 51-59, as well as the flow rate of hydraulic pumps 31-33, based on the instruction information of the operation of a remote operating device that remotely indicative of the movement of the rotating body 3 and the working devices 21, 22, and 23. Alternatively, control devices 200 and 200A may be configured to control the opening of directional control valves 37-42 and 44-46 and flow control valves 51-59 and the flow rate of hydraulic pumps 31-33 based on indication information generated by themselves to enable the rotating body 3 and working devices 21, 22, and 23 to perform actions that meet specified conditions through automatic control.

[0149] Furthermore, in the first and second embodiments described above, examples are shown using flow control valves 51-59 as control valves capable of controlling the flow rate of hydraulic oil supplied to the hydraulic actuators 25-27 of the drive unit 4. However, as control valves capable of controlling the flow rate of hydraulic oil supplied to the hydraulic actuators 25-27, directional control valves that control the supply and discharge direction of hydraulic oil relative to the hydraulic actuators can also be used. In this configuration, the flow rate of hydraulic oil supplied to the hydraulic actuators 25-27 can be controlled by the inlet throttling opening area of ​​the directional control valve.

[0150] Explanation of reference numerals in the attached figures

[0151] 1…Hydraulic excavator (construction machinery), 4…Working device, 23…Bucket (working tool), 25…Boom cylinder (hydraulic actuator), 26…Stick cylinder (hydraulic actuator), 27…Bucket cylinder (hydraulic actuator), 31…First hydraulic pump (hydraulic pump), 32…Second hydraulic pump (hydraulic pump), 33…Third hydraulic pump (hydraulic pump), 37, 38, 39, 40, 41, 42, 45, 46…Directional control valve, 51, 52, 53, 54, 55, 56, 58, 59…Flow control valve (control valve), 121, 122, 123…Pressure sensor (pressure detection device), 124, 125, 126…Pressure sensor (pressure detection device), 131, 132, 133, 134, 135…IMU (attitude detection device), 200, 200A…Control device.

Claims

1. An engineering machine, comprising: A working device, which includes working tools; At least one hydraulic actuator drives the working device; A hydraulic device capable of adjusting the flow rate of hydraulic oil supplied to the hydraulic actuator; A control device that controls the hydraulic actuator via the hydraulic equipment to ensure that the working tool moves without exceeding the target surface set as the work object; A posture detection device detects the posture of the working device. Its features are, The control device, based on the detection information from the posture detection device and the setting information of the target surface, calculates the speed of the hydraulic actuator that enables the working tool to meet the conditions as the target speed. It then calculates the target value of the hydraulic equipment corresponding to the calculated target speed of the hydraulic actuator. If the calculated target value of the hydraulic equipment is smaller than the lower limit value that ensures the allowable accuracy of the hydraulic equipment for flow control, the control device calculates the speed of the hydraulic actuator obtained based on the lower limit value as the limiting speed of the hydraulic actuator. Based on the calculated limiting speed of the hydraulic actuator, the control device recalculates the target speed of the hydraulic actuator that enables the working tool to meet the conditions. Finally, the control device uses the target value of the hydraulic equipment as the control target, corresponding to the recalculated target speed of the hydraulic actuator, to control the hydraulic equipment.

2. The engineering machinery according to claim 1, characterized in that, The at least one hydraulic actuator driving the working device is composed of multiple hydraulic actuators. The target speed of the hydraulic actuators in the control device is calculated not only based on the detection information of the posture detection device and the target surface setting information, but also based on the movement direction of the working tool obtained according to the instruction information indicating the action of the working device, and the target speed of each of the plurality of hydraulic actuators is calculated accordingly. The recalculation of the target speed of the hydraulic actuator in the control device, based on the calculated limit speed, calculates the speed of the plurality of hydraulic actuators that enable the working tool to maintain the direction of movement and satisfy the condition.

3. The engineering machinery according to claim 1, characterized in that, The hydraulic device is a flow control valve capable of controlling the flow rate of hydraulic oil supplied to the hydraulic actuator. The construction machinery also has a pressure detection device for detecting the differential pressure before and after the flow control valve. The target value of the hydraulic equipment is the target opening area of ​​the flow control valve, calculated based on the target flow rate of the hydraulic actuator obtained from the calculated target speed of the hydraulic actuator and the detection value of the pressure detection device. The lower limit value is a preset limit opening area of ​​the flow control valve based on the accuracy of the flow control. The speed limit calculation of the hydraulic actuator in the control device is based on the flow rate calculated using the limit opening area of ​​the flow control valve and the detection value of the pressure detection device.

4. The engineering machinery according to claim 3, characterized in that, The construction machinery also includes: a directional control valve, which controls the flow direction of hydraulic oil supplied to the hydraulic actuator and can control the flow of hydraulic oil discharged from the hydraulic actuator. The flow control valve is located upstream of the directional control valve. The pressure detection device includes pressure sensors that detect the inlet throttling pressure and the outlet throttling pressure of the hydraulic actuator. The control device controls the outlet throttling opening of the directional control valve based on the thrust or pressure information of the hydraulic actuator obtained from the detection value of the pressure sensor.

5. The engineering machinery according to claim 1, characterized in that, The hydraulic equipment is a hydraulic pump that supplies hydraulic oil to the hydraulic actuator. The target value of the hydraulic equipment is the target flow rate of the hydraulic pump, calculated based on the target flow rate of the hydraulic actuator obtained from the calculated target speed of the hydraulic actuator. The lower limit value is a preset limit flow rate for the hydraulic pump based on the accuracy of the flow control. The speed limit calculation of the hydraulic actuator in the control device is based on the limit flow rate of the hydraulic pump.

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