JP6565614B2 - Swivel hydraulic work machine - Google Patents

Description

  The present invention relates to a swing type hydraulic working machine such as a hydraulic excavator.

  A swivel hydraulic working machine generally includes a lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, a working device that is mounted on the upper revolving body, and a hydraulic motor that revolves the upper revolving body. A swing motor, a hydraulic pump that discharges hydraulic fluid to be supplied to the swing motor, and a swing control valve that is interposed between the hydraulic pump and the swing motor. The turning control valve opens and closes according to the operation of the turning operation lever by the operator, and changes the flow rate of the hydraulic oil supplied to the turning motor among the hydraulic oil discharged from the hydraulic pump.

  The hydraulic oil discharged from the hydraulic pump is often used not only for the swing motor but also for other hydraulic actuators (for example, boom cylinders). In this case, the other hydraulic actuator is connected to the hydraulic pump via a dedicated control valve different from the turning control valve. That is, the hydraulic pump is used both for supplying hydraulic oil to the swing motor and for supplying hydraulic oil to the other hydraulic actuators.

  In this type of work machine, when the turning operation and the operation for moving the other hydraulic actuator are performed at the same time, that is, in the combined operation, the hydraulic pump supplies the turning motor and the other hydraulic actuator. It is important to distribute the flow rate of hydraulic oil. For example, Patent Document 1 discloses that in a construction machine in which a swing control valve and a boom raising speed increasing control valve for speeding up a boom raising operation are connected in parallel to a common hydraulic pump, a turning motor is passed through the turning control valve. And a flow rate distribution control unit that controls the distribution of the flow rate of the hydraulic oil supplied to the boom cylinder and the flow rate of the hydraulic oil supplied to the boom cylinder through the boom raising acceleration control valve. When a combined operation of raising the boom and turning is detected, the flow rate distribution control unit increases the flow rate of the hydraulic oil supplied to the boom cylinder so as to give priority to the raising of the boom raising speed at the start of the combined operation. On the other hand, when the boom is raised to a predetermined height, control is performed to give priority to the flow rate on the turning side.

JP 2005-83427 A

  When the turning drive is performed in a state where the upper swing body is inclined rather than horizontal, depending on the turning direction of the upper swing body, the upper swing body must be driven against gravity acting on the upper swing body, The pressure of the hydraulic oil required for driving becomes higher than the pressure required for driving in the horizontal state. In this case, if much of the flow rate of the hydraulic oil is distributed to other hydraulic actuators, the turning driving force is insufficient, and in the worst case, there is a possibility that the turning cannot be started. In such a case, in order to start turning, it is necessary to return the boom control lever from the previous boom raised position to the neutral position to secure the flow rate for turning. Reduces efficiency significantly.

  The present invention relates to a revolving hydraulic working machine in which a revolving motor for revolving an upper revolving body and a specific hydraulic actuator other than the revolving motor are connected to a common hydraulic pump, and the revolving drive regardless of the inclination of the upper revolving body It is an object of the present invention to provide an apparatus capable of appropriately distributing hydraulic oil to the swing motor and the other hydraulic actuators so as to be able to reliably perform the operation.

The provided swing hydraulic working machine has a lower traveling body and a swing body reference direction, and is mounted on the lower traveling body, and an angle of the swing body reference direction with respect to the lower traveling body as viewed from above. The upper swivel body that can swivel so as to change, the working device mounted on the upper swivel body, the hydraulic pump that discharges hydraulic oil, and the hydraulic oil discharged by the hydraulic pump is supplied to operate. A hydraulic motor, which is interposed between the hydraulic pump and the swing motor, and capable of bidirectionally rotating the upper swing body in response to the supply of the hydraulic oil. A swing control valve that opens and closes so as to change a swing flow rate that is a flow rate of hydraulic oil supplied to the swing motor, and a specific hydraulic actuator that is different from the swing motor, and is provided by the hydraulic pump The specific flow rate of the hydraulic oil supplied from the hydraulic pump to the specific actuator is changed between the specific pump that operates upon receiving the supplied hydraulic oil, and the hydraulic pump and the specific actuator. An actuator control valve that opens and closes to operate, an actuator operation device that is provided with an actuator operation for commanding the operation of the specific actuator, a turning direction detection unit that detects a turning direction of the upper turning body, and the turning body a tilt detection unit that detects an inclination direction and inclination angle of the upper swing body as viewed from the reference direction, wherein the actuator operating device operation given to and turning direction of the turning direction detecting section detects inclination Hasuken out portion is detected The actuator to control the flow rate of the actuator based on an inclination angle of the actuator. And a control system for operating the control valve, the. The control system includes a basic control unit that changes an opening degree of the actuator control valve according to the actuator operation given to the actuator operation unit, and the turning direction detection unit based on the inclination direction detected by the inclination detection unit. It is determined whether or not the turning direction detected by the above is an uphill direction against the gravity acting on the upper turning body, and when it is determined that the turning direction is the uphill direction, the greater the inclination angle of the upper turning body, the greater the actuator flow rate. An actuator flow rate restriction unit that reduces the opening of the actuator control valve so as to restrict the flow rate.

  In this swing type hydraulic working machine, the distribution of hydraulic oil flow considering the inclination state of the upper swing body, that is, the ratio between the swing flow rate and the actuator flow rate is determined. Even if the direction, that is, the direction in which the upper turning body must be moved against the gravity acting on the upper turning body, it is possible to ensure the turning flow rate necessary for turning in the uphill direction. is there. Specifically, when the turning direction of the upper swing body is the uphill direction, the control system of the swing type hydraulic working machine restricts the actuator flow rate as the inclination angle increases, so that It is possible to secure a turning flow rate required for turning the upper turning body, that is, a flow rate of hydraulic oil to be supplied to the turning motor. On the other hand, when the turning direction of the upper swing body is not the uphill direction, the actuator flow rate is not limited, and even in the uphill direction, when the inclination angle is small, the actuator flow rate limit is also small, It is avoided that the operating speed of the specific actuator is suppressed unnecessarily.

When the actuator control valve is a pilot switching valve that operates upon receiving a supply of pilot pressure, the basic control unit receives a command signal and changes a pilot pressure that is input to the actuator control valve. An operation valve, and a basic command signal calculation unit that calculates a basic command signal based on an operation given to the actuator operation unit, and the actuator flow rate limiting unit is configured to perform the operation when the turning direction is not the uphill direction. The basic command signal calculated by the basic command signal calculation unit is directly input to the pilot pressure control valve as a final command signal, and when the turning direction is the uphill direction, the basic command signal is set according to the inclination angle. It is preferable to input the reduced signal as a final command signal to the pilot pressure control valve.

  In this case, for example, the actuator flow rate restriction unit calculates a restriction command signal that is a preset restriction command signal and has a characteristic that the larger the inclination angle, the smaller the inclination angle becomes. When the turning direction is the uphill direction, a restriction command signal calculation unit, and a lower one of the basic command signal and the restriction command signal is selected as the final command signal and input to the pilot pressure control valve It is preferable to include a final command signal determination unit. The actuator flow rate restricting unit can realize a preferable control of the actuator flow rate restriction by a simple arithmetic operation of low order selection between the basic command signal and the restriction command signal.

  In the case where the swing hydraulic working machine further includes a swing operation device to which a swing operation, which is an operation for commanding the operation of the swing motor, is provided, the actuator flow rate limiting unit decreases the actuator flow rate as the swing operation is smaller. It is preferable to relax the restrictions. The restriction on the actuator flow rate based on the turning operation is reduced by increasing the actuator flow rate when the turning operation is small, that is, when there is no request for a large turning driving force, compared to when the turning operation is large. It is possible to prevent the operating speed from being unnecessarily suppressed.

  For example, when the actuator flow rate restriction unit includes the restriction command signal calculation unit and the final command signal determination unit, the restriction command signal calculation unit has a small turning operation based on the turning operation in addition to the restriction command signal. It is preferable to calculate a restriction relaxation command signal having such a large characteristic that, when the restriction relaxation command signal is larger than the restriction command signal, change the restriction command signal to the restriction relaxation command signal. The actuator flow rate restriction unit relaxes a suitable actuator flow rate restriction by a simple calculation operation of high-level selection between the calculated original restriction command signal and a restriction relaxation command signal calculated separately. Can do.

  As described above, according to the present invention, there is provided a revolving hydraulic working machine in which a revolving motor for revolving the upper revolving structure and a specific hydraulic actuator other than the revolving motor are connected to a common hydraulic pump, There is provided a device capable of appropriately distributing hydraulic oil to the swing motor and the specific hydraulic actuator so as to reliably enable the swing drive of the upper swing body regardless of the inclination.

1 is a diagram showing a hydraulic excavator that is a hydraulic working machine according to an embodiment of the present invention. FIG. It is a figure which shows the hydraulic circuit mounted in the said hydraulic shovel. It is a figure which shows the state which looked at the upper turning body of the said hydraulic excavator from the front side of the turning body front-back direction, and the said upper turning body inclined to the left. It is a figure which shows the state which looked at the upper turning body of the said hydraulic excavator from the front side of the turning body front-back direction, and the said upper turning body inclined to the right. It is a block diagram which shows the function structure of the controller mounted in the said hydraulic shovel. It is a flowchart which shows the calculation control operation | movement which the said controller performs. It is a graph which shows the characteristic with respect to the boom raising pilot pressure of the basic command current calculated by the said controller. It is a graph which shows the characteristic with respect to the inclination angle of the limitation command electric current calculated by the said controller. It is a graph which shows the characteristic with respect to the turning pilot pressure of the restriction | moderation relaxation command electric current calculated by the said controller.

  Preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a hydraulic excavator according to the embodiment. The present invention is not limited to the hydraulic excavator shown here, and can be widely applied to work machines that include an upper swing body and operate using hydraulic pressure as a main power.

  The hydraulic excavator includes a lower traveling body 10 capable of traveling on the ground G, an upper swing body 12 mounted on the lower traveling body 10, and a work device 14 mounted on the upper swing body 12. The upper swing body 12 is set with a swing body longitudinal direction as a swing body reference direction, a cab 16 serving as a driver's cab is provided in a front portion of the swing body longitudinal direction, and the working device 14 is mounted on the rear swing body. The engine room 18 is provided in the part.

  The working device 14 includes a boom 20, an arm 22, a bucket 24, and a plurality of extendable hydraulic cylinders provided for driving the boom 20, that is, a boom cylinder 26, an arm cylinder 27, and a bucket cylinder 28. Among these, the boom cylinder 26 which is a hydraulic actuator for driving the boom 20 to move up and down corresponds to the “specific actuator” according to the present invention.

  The boom 20 has a base end portion that is supported at the front end of the upper swing body 12 so as to be able to undulate, that is, turnable around a horizontal axis, and a distal end portion on the opposite side. The arm 22 has a base end portion that is rotatably attached to the tip end portion of the boom 20 around a horizontal axis, and a tip end portion on the opposite side, and the bucket 24 is rotatable at the tip end portion. Mounted on. Each of the cylinders 26 to 28 is supplied with hydraulic oil and operates in the expansion / contraction direction to rotate the drive target corresponding to the cylinder 26. For example, the boom cylinder 26 is interposed between the boom 20 and the upper swing body 12 so as to move the boom 20 in the raising direction and the lowering direction by extension and contraction, respectively.

  FIG. 2 shows a portion of the hydraulic circuit mounted on the hydraulic excavator that is involved in the turning drive of the upper turning body 12 and the raising / lowering drive of the boom 20. As shown in FIG. 2, the hydraulic circuit includes a first main pump that is a plurality of hydraulic pumps connected to the output shaft of the engine 30 in addition to the boom cylinder 26 corresponding to the “specific actuator” as described above. 31, a second main pump 32 and a pilot pump 34, a swing motor 36 which is a hydraulic motor for driving the swing of the upper swing body 12, a boom first speed control valve 38, a boom second speed control valve 40, a swing A control valve 42, a boom remote control valve 50, and a swing remote control valve 52 are included.

  Each of the pumps 31, 32, and 34 is driven by the engine 30, thereby discharging oil in the tank. The first and second main pumps 31 and 32 discharge hydraulic oil for directly moving a hydraulic actuator to be driven. The pilot pump 34 discharges pilot oil for supplying a pilot pressure for opening and closing the control valves 38, 40, 42 to the control valves 38, 40, 42.

  The turning motor 36 has an output shaft that rotates in response to the supply of the hydraulic oil, and the output shaft is connected to the upper turning body 12 so as to turn the upper turning body 12 in both left and right directions. . Specifically, the turning motor 36 has a pair of ports 36a and 36b, and the output shaft rotates in a direction corresponding to the one port by receiving supply of hydraulic oil to one of the ports. At the same time, the hydraulic oil is discharged from the other port.

  Each of the control valves 38, 40, 42 comprises a hydraulic pilot switching valve, and receives a pilot pressure supplied from the pilot pump 34 to operate in a valve opening direction with a stroke corresponding to the magnitude of the pilot pressure. Accordingly, the hydraulic oil is allowed to be supplied to the corresponding hydraulic actuator at a flow rate corresponding to the pilot pressure. Therefore, the flow rate can be controlled by changing the pilot pressure.

  The boom first speed control valve 38 is a valve that guides hydraulic oil discharged from the first main pump 31 to the boom cylinder 26 as main hydraulic oil for extending and contracting the boom cylinder 26. It is interposed between the main pump 31 and the boom cylinder 26. Specifically, the first boom speed control valve 38 is provided in the middle of a center bypass line 33 that can directly pass through the first main pump 31 and the tank.

  The boom first speed control valve 38 is a three-position pilot switching valve and has a pair of pilot ports 39A and 39B. The boom first speed control valve 38 is maintained at a neutral position 38n when the pilot pressure supplied to the pilot ports 39A and 39B is 0 or very small, and the first main pump 31 and the boom cylinder 26 are disconnected from each other. Then, by opening the center bypass line 33, the hydraulic oil from the first main pump 31 is released to the tank as it is. When a pilot pressure of a certain level or higher is supplied to the pilot port 39A, the boom first speed control valve 38 shifts from the neutral position 38n to the boom raising position 38a with a stroke corresponding to the magnitude of the pilot pressure. At a position 38a, a pump connected to the first main pump 31 so as to allow hydraulic oil from the first main pump 31 to be supplied to the head side chamber 27H of the boom cylinder 26 at a flow rate corresponding to the stroke. The rod side chamber line 37R connected to the rod side chamber 27R so as to connect the line 35 and the head side chamber line 37H connected to the head side chamber 27H and to release hydraulic oil discharged from the rod side chamber 27R of the boom cylinder 26 to the tank. Is connected to the tank, whereby the boom cylinder 26 is Actuating the extension direction, that is the boom-up direction at a speed corresponding to the serial stroke. Conversely, when a pilot pressure of a certain level or higher is supplied to the pilot port 39B, the boom first speed control valve 38 shifts from the neutral position 38n to the boom lowering position 38b with a stroke corresponding to the magnitude of the pilot pressure, At the boom lowering position 38b, the pump line 35 and the rod side chamber are allowed to allow hydraulic oil from the first main pump 31 to be supplied to the rod side chamber 27R of the boom cylinder 26 at a flow rate corresponding to the stroke. The head side chamber line 37H is connected to the tank so that the hydraulic oil discharged from the head side chamber 27H of the boom cylinder 26 is released to the tank. It is operated in the contraction direction, that is, the boom lowering direction at a speed corresponding to the stroke.

  The boom second speed control valve 40 and the swing control valve 42 are interposed between the second main pump 32, the boom cylinder 26 and the swing motor 36, respectively. In other words, the hydraulic fluid discharged from the second main pump 32 passes through the boom second speed control valve 40 and the swing control valve 42, respectively, and the head side chamber 27H of the boom cylinder 26 and the swing motor 36. The distribution ratio changes according to the opening degree of each control valve 40, 42. In the circuit shown in FIG. 2, a center bypass line 44 is provided between the second main pump 32 and the tank so that both can be directly passed, and the boom second speed control valve is provided along the center bypass line 44. 40 and the turning control valve 42 are arranged.

  In addition to the hydraulic oil supplied to the boom cylinder 26 through the first boom speed control valve 38, the second boom speed control valve 40 supplies the second hydraulic oil for speeding up the driving in the raising direction of the boom 20. This is an actuator control valve that guides the main pump 32 to the head side chamber 27H of the boom cylinder 26 and controls the flow rate of the hydraulic fluid (actuator flow rate).

  The boom second speed control valve 40 is a two-position pilot switching valve and has a single pilot port 41. The boom second speed control valve 40 is maintained at the neutral position 40n when the pilot pressure supplied to the pilot port 41 is 0 or very small, and shuts off the second main pump 32 and the boom cylinder 26. The center bypass line 44 is opened. When a pilot pressure of a certain level or more is supplied to the pilot port 41, the boom second speed control valve 40 shifts from the neutral position 40n to the boom raising acceleration position 40a with a stroke corresponding to the pilot pressure. In the boom raising acceleration position 40a, the center bypass line is allowed to allow hydraulic oil from the second main pump 32 to be supplied to the head side chamber 27H of the boom cylinder 26 at a flow rate corresponding to the stroke. The hydraulic oil merging line 46 that branches off from 44 and merges with the head side chamber line 37H is opened, and the center bypass line 44 is throttled corresponding to the stroke, thereby driving the boom cylinder 26 in the upward direction. The speed is increased to a degree corresponding to the stroke.

  The turning control valve 42 selectively guides hydraulic oil for driving the turning motor 36 from the second main pump 32 to the first and second ports 36a, 36b of the turning motor 36, and the turning It is a valve that controls the turning flow rate that is the flow rate of the hydraulic oil supplied to the motor 36.

  The turning control valve 42 is a three-position pilot switching valve and has a pair of pilot ports 43A and 43B. The swing control valve 42 is maintained at the neutral position 42n when the pilot pressure supplied to both pilot ports 43A and 43B is 0 or very small, and is provided between the second main pump 32 and the swing motor 36. The center bypass line 44 is opened while being shut off. When a pilot pressure of a certain level or higher is supplied to the pilot port 43A, the turning control valve 42 shifts from the neutral position 42n to the left turning position 42a with a stroke corresponding to the magnitude of the pilot pressure. In 42a, for the turning branching from the center bypass line 44, the hydraulic oil from the second main pump 32 is allowed to be supplied to the first port 36a of the turning motor 36 at a flow rate corresponding to the stroke. The supply line 48 and the first port line 45A connected to the first port 36a are connected and the center bypass line 44 is throttled corresponding to the stroke, whereby the turning motor 36 is counterclockwise at a speed corresponding to the stroke. Operate in the turning direction. Conversely, when a pilot pressure of a certain level or higher is supplied to the pilot port 43B, the turning control valve 42 shifts from the neutral position 42n to the right turning position 42b with a stroke corresponding to the magnitude of the pilot pressure, At the right turning position 42b, the turning supply line is allowed to allow hydraulic oil from the second main pump 32 to be supplied to the second port 36b of the turning motor 36 at a flow rate corresponding to the stroke. 48 and a second port line 45B connected to the second port 36b, and the center bypass line 44 is throttled corresponding to the stroke, whereby the turning motor 36 turns right at a speed corresponding to the stroke. Operate in the direction.

  The boom remote control valve 50 is an actuator operating device to which an operation (actuator operation) for commanding the operation of the boom cylinder 26 as a specific actuator is given, and the pilot pressure corresponding to the operation is controlled by the first speed control of the boom. It is interposed between the pilot pump 34 and the first boom speed control valve 38 so as to be alternatively supplied to the pilot ports 39A and 39B of the valve 38.

  Specifically, the boom remote control valve 50 includes a boom operation lever 50a that is an operation member that can be rotated in response to the operation, and a valve main body that opens and links with the movement of the boom operation lever 50a. 50b. The valve body 50b has an inlet port connected to the pilot pump 34 and a pair of outlet ports, and the pair of outlet ports is connected to the boom first speed control valve 38 via boom pilot lines 54A and 54B, respectively. Are connected to the pilot ports 39A and 39B. When the boom operation lever 50a is in a neutral position without being operated, the valve body 50b maintains a valve closing state that shuts off the pilot pump 34 and the pilot ports 39A and 39B, and the boom operation lever 50a When the pivoting operation is performed from the neutral position, a pilot pressure having a magnitude corresponding to the amount of the pivoting operation is supplied to the pilot port corresponding to the direction of the pivoting operation among the pilot ports 39A and 39B. In addition, the valve is opened according to the turning operation. Therefore, the boom second speed control valve 40 is opened with a stroke corresponding to the amount of the operation in a direction corresponding to the direction of the operation given to the boom operation lever 52a.

  The turning remote control valve 52 is a turning operation device to which a turning operation that is an operation for commanding the operation of the turning motor 36 is given, and a pilot pressure corresponding to the operation is supplied to a pilot port 43A of the turning control valve 42. , 43B is interposed between the turning control valve 42 and the pilot pump 34 so as to be supplied alternatively.

  Specifically, the turning remote control valve 52 includes a turning operation lever 52a that is an operation member that can turn in response to the operation, and a valve main body 52b that operates in conjunction with the movement of the turning operation lever 52a. Have. The valve main body 52b has an inlet port connected to the pilot pump 34 and a pair of outlet ports, and the pair of outlet ports are pilots of the swing control valve 42 via swing pilot lines 56A and 56B, respectively. They are connected to ports 43A and 43B, respectively. When the turning operation lever 52a is in the neutral position without being operated, the valve body 52b maintains a valve closing state that shuts off the pilot pump 34 and the pilot ports 43A, 43B, and the turning operation lever 52a When the rotation is performed from the neutral position, a pilot pressure having a magnitude corresponding to the amount of the rotation operation is supplied to the pilot port corresponding to the direction of the rotation operation among the pilot ports 43A and 43B. In addition, the valve is opened according to the turning operation. Therefore, the turning operation valve 42 opens in a direction corresponding to the direction of operation given to the turning operation lever 52a with a stroke corresponding to the amount of the operation.

  As described above, the pilot port 41 of the boom second speed control valve 40 corresponding to the “actuator control valve” is connected to the pilot pump 34 via the dedicated boom second speed pilot line 58 independent of the boom remote control valve 50. The boom second speed pilot line 58 is provided with a pilot pressure operation valve 68 which will be described in detail later.

  The hydraulic excavator according to this embodiment further includes a plurality of sensors shown in FIG. The plurality of sensors includes a boom raising pilot pressure sensor 60, a pair of turning pilot pressure sensors 62 </ b> A and 62 </ b> B, and a tilt sensor 64.

  The boom raising pilot pressure sensor 60 detects a boom raising pilot pressure Pb which is a pilot pressure supplied from the boom remote control valve 50 to the pilot port 38A of the boom first speed control valve 38 to detect an electric signal, that is, a boom pilot pressure. It is a pressure sensor that converts it into a signal.

  The turning pilot pressure sensors 62A and 62B detect turning pilot pressures Psa and Psb, which are pilot pressures supplied from the turning remote control valve 52 to the pilot ports 43A and 43B of the turning control valve 42, and are used as electrical signals, that is, turning pilots. It is a pressure sensor that converts pressure detection signals. These turning pilot pressure sensors 62 </ b> A and 62 </ b> B also correspond to a turning direction detection unit that detects the turning direction of the upper turning body 12.

  The tilt sensor 64 is attached to the upper swing body 12 and constitutes a tilt detection unit that detects the tilt direction and tilt angle of the upper swing body 12 as viewed from the swing body longitudinal direction, which is the swing body reference direction. Specifically, as shown in FIGS. 3 and 4, the tilt sensor 68 detects a tilt angle θ in the left-right direction when the upper swing body 12 is viewed from the front side in the front-rear direction of the swing body, and detects this. It converts into the inclination detection signal which is a signal. The inclination angle θ is given a positive or negative sign depending on the inclination direction. Specifically, a positive sign is given when the upper swing body 12 is tilted to the left as shown in FIG. 3, and a negative sign is given when it is tilted to the right as shown in FIG. It is done. A well-known sensor can be applied to the tilt sensor 64. Generally, a physical quantity that changes with the tilt (the magnitude of gravity acting on the weight in a specific direction, the capacitance, the distortion of the test object, etc.) ) Is used.

  This hydraulic excavator further controls the flow rate of hydraulic oil that corresponds to the “actuator flow rate” according to the present invention and that is supplied from the boom second speed control valve 42 to the head side chamber 27H of the boom cylinder 26. Control system. The control system includes an operation given to the boom remote control valve 50 corresponding to an “actuator operation device”, an operation given to the turning remote control valve 52 corresponding to a “swing operation device”, and a swing of the upper swing body 12. The actuator flow rate is controlled based on the direction and the tilt angle detected by the tilt sensor 64 (including the tilt direction).

  The control system according to this embodiment includes the pilot pressure operation valve 68 and the controller 70 shown in FIGS.

  The pilot pressure operation valve 68 changes the pilot pressure input to the pilot port 41 of the boom second speed control valve 40 in response to an input of a command signal. Specifically, the pilot pressure operation valve 68 according to this embodiment is an electromagnetic proportional pressure reducing valve having a solenoid 69 and opens at an opening proportional to a command current that is an excitation current supplied to the solenoid 69. Thus, the pilot pressure supplied from the pilot pump 34 to the pilot port 41 of the boom second speed control valve 40, that is, the boom speed increasing pilot pressure is changed.

  The controller 70 includes a basic command current calculation unit 72, a limit command current calculation unit 74, and a final command current determination unit 76 as shown in FIG.

  The basic command current calculation unit 72, together with the pilot pressure operation valve 68, sets the opening degree of the boom second speed control valve 40 according to an operation given to the boom operation lever 50a of the boom remote control valve 50 which is an actuator operation device. The basic control unit to be changed is configured. Specifically, the basic command current calculation unit 72 has a basis for the command current that determines the opening degree of the pilot pressure operation valve 68 based on the boom raising pilot pressure Pb detected by the boom raising pilot pressure sensor 60. The basic command current Ibo is calculated. In this embodiment, the characteristic as shown in FIG. 7 is determined for the relationship between the boom raising pilot pressure Pb and the basic command current Ibo, and the basic command current calculation unit 72 stores the characteristic, Based on this, the basic command current Ibo corresponding to the boom raising pilot pressure Pb is determined.

  The restriction command current calculation unit 74 and the final command current determination unit 76 constitute an actuator flow rate restriction unit. The actuator flow restriction unit is configured so that the turning direction of the upper swing body 12 detected by the swing pilot pressure sensors 62A and 62B is based on the tilt direction of the upper swing body 12 detected by the tilt sensor 64. It is determined whether the direction is an uphill direction against the gravity acting on 12 or a downhill direction according to the gravity, and when it is determined that the direction is an uphill direction, the greater the inclination angle of the upper swing body 12, the greater the actuator flow, The opening degree of the boom second speed control valve 40 is decreased so as to limit the flow rate of the hydraulic oil supplied to the head side chamber 27H of the boom cylinder 26 through the boom second speed control valve 40.

  Specifically, the limit command current calculation unit 74 stores a limit command current Ir set in advance according to the tilt angle θ, calculates a limit command current Ir corresponding to the tilt angle θ, and outputs this. To do. The limit command current calculation unit 74 according to this embodiment stores a characteristic that the limit command current Ir decreases as the tilt angle θ increases when the tilt angle θ is greater than or equal to a certain value. The limit command current Ir corresponding to the tilt angle θ is determined based on the above.

  FIG. 8 shows an example of the characteristics. In this characteristic, a limit command current Ir equivalent to the maximum value of the basic command current Ibo is given in a range where the tilt angle θ is less than a certain value, and the tilt angle θ (more precisely, the absolute value of the tilt angle θ) increases. As the limit command current Ir decreases and the inclination angle θ (absolute value thereof) exceeds the allowable range, the limit command current Ir is suppressed to the minimum value.

  When the turning direction of the upper swing body 12 is not the uphill direction, the final command current determining unit 76 uses the basic command current Ibo calculated by the basic command current calculation unit 72 as the final command current Ib as it is as the pilot pressure. Input to the operation valve 68. On the other hand, the final command current determination unit 76 calculates the basic command current Ibo calculated by the basic command current calculation unit 72 and the limit command current calculation unit 74 when the turning direction is the uphill direction. The limited command current Ir, that is, a signal for reducing the command current from the basic command current Ibo in accordance with the inclination angle θ is compared, and the lower one is selected as the final command current Ib to select the pilot pressure Input to the operation valve 68.

  Furthermore, the actuator flow rate restriction unit according to this embodiment has a function of relaxing the restriction on the actuator flow rate as the turning operation given to the turning remote control valve 52 is smaller. Specifically, the limit command current calculation unit 74 has a function of calculating a limit relaxation command current Irr for relaxing the limitation in addition to the original limit command current Ir, and the limit command current Ir more than the limit command current Ir. A function of changing the restriction command current Ir to the restriction relaxation command current Irr when the restriction relaxation command current Irr is large. The restriction relaxation command current Irr is based on the turning pilot pressure Ps (the higher one of the pilot pressures Psa and Psb detected by the turning pilot pressure sensors 62A and 62B) corresponding to the magnitude of the turning operation. The smaller the value, the larger the characteristic. In other words, the limit command current calculation unit 74 according to this embodiment considers the relaxation of restrictions based on a high-order selection between a value calculated as the original limit command current Ir and a value calculated as another limit relaxation command current Irr. To determine the final limit command current Ir.

  FIG. 9 shows an example of the characteristic of the restriction relaxation command current Irr with respect to the turning pilot pressure Ps. According to this characteristic, the maximum value of the restriction relaxation command current Irr is given in the range where the turning pilot pressure Ps is less than a certain value, and the restriction relaxation command current Irr decreases as the value deviates from the range. When the turning pilot pressure Ps exceeds the allowable range, the restriction relaxation command current Irr is suppressed to the minimum value. The limit command current calculation unit 74 stores such characteristics and specifies the limit relaxation command current Irr corresponding to the turning pilot pressure Ps based on the characteristics.

  Next, the arithmetic control operation actually performed by the controller 70 will be described with reference to the flowchart of FIG.

  The controller 70 takes in various signals input from the sensors 60, 62A, 62B, 64, etc. (step S1). The basic command current calculation unit 72 of the controller 70 calculates a basic command current Ibo corresponding to a detection signal related to the boom raising pilot pressure Pb among the various signals (step S2). This basic command current Ibo is a current that increases as the boom raising pilot pressure Pb increases as shown in FIG. 7, and therefore, the boom raising operation and the opening degree of the boom second speed control valve 40 are linked. Command current.

  Next, the final command current determination unit 76 of the controller 70 determines whether or not the turning direction of the upper turning body 12 determined based on the turning pilot pressures Psa and Psb detected by the turning pilot pressure sensors 62A and 62B is the uphill direction. Is determined (step S3). For example, as shown in FIG. 3, when the upper swing body 12 is tilted to the left when the upper swing body 12 is viewed from the front side in the longitudinal direction of the swing body (that is, when the tilt angle θ is positive), the swing direction is When viewed from the operator in the cab 16, the turning direction is determined to be the uphill direction, and when the turning direction is the right direction, the downhill direction is determined. Conversely, when the upper swing body 12 is tilted to the right as shown in FIG. 4 (that is, when the tilt angle θ is negative), when the swing direction is the left direction as viewed from the operator, the swing direction is It is determined that the direction is downhill, and when the direction is rightward, it is determined as the uphill direction. In addition, in the case of “not uphill direction”, in addition to the case where the turning direction is the downhill direction, the upper turning body 12 is horizontal, or the upper turning body 12 is not turning (that is, turning and turning). This includes the case where the combined operation with the boom raising is not performed.

  When the final command current determination unit 76 determines that the turning direction is not the uphill direction (NO in step S3), that is, when the upper turning body 12 is not in a state of turning against the gravity acting thereon, The basic command current Ibo is set to the final command current Ib as it is (step S4).

  On the other hand, when it is determined that the turning direction is the uphill direction (YES in step S3), the limit command current Ir is calculated by the limit command current calculation unit 74 (steps S5 to S8). Specifically, the limit command current calculation unit 74 calculates a limit command current Ir corresponding to the inclination angle θ based on the characteristics shown in FIG. 8 (step S5), and turns based on the characteristics shown in FIG. The restriction relaxation command current Irr corresponding to the pilot pressure Ps (the higher pilot pressure of the two turning pilot pressures Ps) is calculated (step S6). The limit command current calculation unit 74 maintains the limit command current Ir as it is when the limit command current Ir is equal to or greater than the limit relaxation command current Irr (NO in step S7). If Irr exceeds the limit command current Ir (YES in step S7), the limit command current Ir is changed to the limit relaxation command current Irr (step S8).

  The final command current determining unit 76 compares the limit command current Ir determined as described above with the basic command current Ibo (step S9). The final command current determination unit 76 sets the basic command current Ibo to the final command current Ib when the basic command current Ibo is equal to or less than the limit command current Ir (YES in step S9) (step S10). If the limit command current Ir is smaller than the basic command current Ibo (NO in step S9), the limit command current Ir is set as the final command current Ib (step S11).

  The final command current determination unit 76 inputs the final command current Ib determined as described above to the pilot pressure operation valve 68 (step S12). Accordingly, the pilot pressure operation valve 68 is opened at an opening proportional to the final command current Ib, and the pilot pressure corresponding to the opening is supplied to the pilot port 41 of the boom second speed control valve 40. Allow. Thus, the flow rate of the hydraulic oil (actuator flow rate) supplied to the boom cylinder 26 through the boom second speed control valve 40 among the hydraulic oil discharged from the second main pump 32 is controlled.

  In the hydraulic excavator described above, hydraulic oil supplied from the common second main pump 32 to the head side chamber 27H of the boom cylinder 26 and the swing motor 36 through the boom second speed control valve 40 and the swing control valve 42, respectively. Is distributed in consideration of the tilt state of the upper swing body 12 detected by the tilt sensor 64, that is, the ratio between the swing flow rate and the actuator flow rate is determined, so that the swing direction is the uphill direction, that is, the upper portion. Even in the direction in which the upper revolving body must be moved against the gravity acting on the revolving body 12, it is possible to ensure a turning flow rate necessary for turning in the uphill direction.

  Specifically, the control system includes the pilot pressure operation valve 68 and the controller 70, and the control system including the pilot pressure operation valve 68 and the controller 70 has a larger inclination angle of the upper swing body 12 when the turning direction is the uphill direction (this implementation). In this embodiment, the actuator flow rate, that is, the flow rate supplied to the head side chamber 27H through the boom second speed control valve 40 is limited by increasing the absolute value of the detection signal of the tilt angle θ output from the tilt sensor 64. The turning flow rate necessary for turning the upper turning body 12 in the uphill direction, that is, the flow rate of hydraulic oil to be supplied to the turning motor 36 through the turning control valve 42 can be secured. On the other hand, the control system does not limit the flow rate of the actuator when the turning direction is not the uphill direction, and when the inclination angle of the upper turning body 12 is small even when the turning direction is the uphill direction. Since the restriction on the actuator flow rate is also kept small, the necessary turning flow rate can be ensured without wastefully suppressing the boom raising speed by the boom cylinder 26.

  In particular, the controller 70 according to this embodiment has a basic command current calculation unit 72 and a limit command current calculation unit 74 for storing characteristics as shown in FIGS. 7 and 8, for example, and is calculated by both. Since the final command current Ib is determined by a low-order selection from the basic command current Ibo and the limit command current Ir, it is possible to execute control for limiting the actuator flow rate without performing a complicated calculation operation.

  Further, the controller 70 according to this embodiment has a function of relaxing the restriction on the actuator flow rate as the turning operation given to the turning remote control valve 52 is smaller. Therefore, when the turning operation is small, that is, a request for a large turning driving force is required. By increasing the actuator flow rate when there is no turning operation compared to when the turning operation is large, it is possible to prevent the boom raising speed from being unnecessarily suppressed.

  Specifically, the limit command current calculation unit 74 according to this embodiment calculates, in addition to the calculation of the original limit command current Ir, the calculation of the limit relaxation command current Irr having a characteristic that becomes larger as the turning operation is smaller, Since it has a function of determining the final limit command current Ir based on the high-order selection of the limit command current Ir and the limit relaxation command current Irr, it is possible to limit the actuator flow rate without performing a complicated calculation operation. Mitigation is possible.

  The present invention is not limited to the embodiment described above. The present invention can include, for example, the following aspects.

1) Specific Actuator and Actuator Control Valve The specific actuator and actuator control valve according to the present invention are not limited to the boom cylinder 26 and the boom second speed control valve 40, respectively. The specific actuator according to the present invention may be another hydraulic actuator included in the working device, for example, an arm cylinder or a bucket cylinder. In addition, the present invention is not limited to a hydraulic excavator, and thus the specific actuator may be included in a working device (for example, a crusher or a lifting device) intended for work other than excavation. In other words, according to the present invention, a swing motor and a specific hydraulic actuator other than the common hydraulic pump are connected to a common hydraulic pump, and an actuator flow rate that is a flow rate of hydraulic oil supplied to the hydraulic actuator is supplied to the swing motor. It can be widely applied to those that affect the swirling flow rate.

2) Detection of tilt state of upper swing body The swing body reference direction of the upper swing body is not limited to the front-rear direction. The revolving unit reference direction may be a direction that changes in the horizontal direction when the upper revolving unit is viewed from above, and may be, for example, the left-right direction of the upper revolving unit 12. In addition, an inclination sensor for detecting the inclination state of the upper swing body may be attached to the lower traveling body. In this case, in addition to the tilt sensor, the tilt detection unit is tilted as viewed from the swing body reference direction of the upper swing body based on the tilt state of the lower traveling body and the swing angle of the upper swing body detected by the tilt sensor. It is good to include the inclination state calculating part which calculates.

3) About the actuator operation device and the turning operation device The actuator operation device and the turning operation device are not limited to the boom remote control valve 50 and the turning remote control valve 52, respectively. The operation device may be a device that generates an electric signal corresponding to an operation given to the operation member (for example, an electric lever device). In this case, pressure sensors such as the boom raising pilot pressure sensor 60 and the turning pilot pressure sensor 62 are unnecessary. On the other hand, even when the actuator control valve and the swing control valve are configured by a pilot switching valve as in the above embodiment, an electromagnetic proportional pressure reducing valve is provided in the middle of the pilot line, and the electromagnetic proportional pressure reducing valve is operated. Thus, the flow rate can be controlled by the actuator control valve or the turning control valve.

4) Restriction of actuator flow rate The circuit for limiting the actuator flow rate is not limited to that shown in FIG. For example, a remote control valve constituting an actuator operating device that outputs a pilot pressure corresponding to actuator operation is connected to a pilot port of an actuator control valve via a pilot line, and the pilot pressure operating valve is located in the middle of the pilot line. For example, an electromagnetic proportional pressure reducing valve may be interposed. In this case, since the remote control valve constitutes a basic control unit that generates a pilot pressure corresponding to a basic command signal and inputs the pilot pressure to the actuator control valve, a basic command signal calculation unit is unnecessary, the electromagnetic proportional pressure reducing valve, etc. As the command signal input to the pilot operation valve, a limit command signal that specifies the degree to which the pilot pressure, which is the basic command signal, is reduced may be calculated.

  Further, the characteristics of the restriction command for the tilt angle can be set freely. For example, since the torque required for the turning drive varies depending on the working posture of the upper turning body, a restriction command may be calculated in consideration of the working posture.

5) Regarding relaxation of restriction on actuator flow rate Specific means for relaxing restriction on the actuator flow rate are not limited to those including calculation of a restriction relaxation command signal such as the restriction relaxation command current Irr. The relaxation can also be executed, for example, by correcting the restriction command signal to increase the restriction command signal according to the turning operation with the basic command signal as an upper limit. Further, relaxation of the restriction on the actuator flow rate may be omitted depending on the specification.

G Ground 10 Lower traveling body 12 Upper turning body 14 Working device 20 Boom 26 Boom cylinder (specific actuator)
27H Head side chamber 27R Rod side chamber 32 Second main pump (hydraulic pump)
36 Rotating motor 40 Boom 2-speed control valve (actuator control valve)
42 Swing control valve 50 Boom remote control valve (actuator actuator)
52 Swing remote control valve (swivel actuator)
62A, 62B Turning pilot pressure sensor (turning direction detector)
64 Tilt sensor (Tilt detector)
68 Pilot pressure control valve 70 Controller 72 Basic command current calculation unit 74 Limit command current calculation unit 76 Final command current determination unit

Claims (5)

A swivel hydraulic working machine,
A lower traveling body,
An upper revolving body having a revolving body reference direction, mounted on the lower traveling body, and capable of turning so that an angle of the revolving body reference direction with respect to the lower traveling body viewed from above is changed;
A working device mounted on the upper swing body;
A hydraulic pump that discharges hydraulic oil;
A hydraulic motor that operates by receiving the supply of hydraulic oil discharged from the hydraulic pump, and that is capable of bidirectionally rotating the upper swing body according to the supply of the hydraulic oil;
A swing control valve that is interposed between the hydraulic pump and the swing motor and opens and closes so as to change a swing flow rate that is a flow rate of hydraulic oil supplied from the hydraulic pump to the swing motor;
A specific hydraulic actuator different from the swing motor, the specific actuator operating by receiving supply of hydraulic oil discharged by the hydraulic pump;
An actuator control valve that is interposed between the hydraulic pump and the specific actuator and opens and closes so as to change an actuator flow rate that is a flow rate of hydraulic oil supplied from the hydraulic pump to the specific actuator;
An actuator operating device provided with an actuator operation for commanding the operation of the specific actuator;
A turning direction detector for detecting a turning direction of the upper turning body;
An inclination detection unit that detects an inclination direction and an inclination angle of the upper revolving body as seen from the revolving body reference direction;
Actuating the actuator control valve to control the actuator flow rate based on the inclination angle which the inclined Hasuken out section and the turning direction of the turning direction detecting unit and an operation applied to said actuator operating device is detected by detecting A control system,
The control system includes a basic control unit that changes an opening degree of the actuator control valve in accordance with the actuator operation given to the actuator operation unit, and the turning direction detection unit based on the inclination direction detected by the inclination detection unit. It is determined whether or not the turning direction detected by the above is an uphill direction against the gravity acting on the upper turning body, and when it is determined that the turning direction is the uphill direction, the greater the inclination angle of the upper turning body, the greater the actuator flow rate. And an actuator flow rate restricting unit for reducing the opening of the actuator control valve so as to restrict the actuator. 2. The swing hydraulic work machine according to claim 1, wherein the actuator control valve is a pilot switching valve that operates by receiving a supply of pilot pressure, and the basic control unit receives an input of a command signal. A pilot pressure operation valve that changes a pilot pressure input to the control valve, and a basic command signal calculation unit that calculates a basic command signal based on an operation given to the actuator actuator, When the turning direction is not the uphill direction, the basic command signal calculated by the basic command signal calculation unit is directly input to the pilot pressure operation valve as the final command signal, and the turning direction is the uphill direction. In the pilot pressure control valve, a signal obtained by reducing the basic command signal according to the tilt angle is used as a final command signal. Forces, turning hydraulic working machine. The swing hydraulic work machine according to claim 2, wherein the actuator flow rate restriction unit is a restriction command signal set in advance and becomes smaller as the inclination angle is larger when the inclination angle is a certain value or more. A limit command signal calculation unit that calculates a limit command signal having characteristics, and when the turning direction is the uphill direction, a lower one of the basic command signal and the limit command signal is selected as the final command signal. And a final command signal determination unit for inputting to the pilot pressure control valve.   The swing hydraulic work machine according to any one of claims 1 to 3, further comprising a swing operation device to which a swing operation that is an operation for instructing an operation of the swing motor is provided, and the actuator flow rate restriction unit Is a revolving hydraulic working machine that relaxes the restriction on the actuator flow rate as the revolving operation becomes smaller.   4. The swing hydraulic work machine according to claim 3, further comprising a swing operation device to which a swing operation that is an operation for commanding an operation of the swing motor is given, wherein the limit command signal calculation unit is configured to transmit the limit command signal. In addition to the signal, a restriction relaxation command signal having a characteristic that becomes larger as the turning operation is smaller is calculated based on the turning operation. When the restriction relaxation command signal is larger than the restriction command signal, the restriction command signal is A swivel hydraulic work machine that changes to a restriction relaxation command signal.

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