Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/08—Superstructures; Supports for superstructures
  • E02F9/10—Supports for movable superstructures mounted on travelling or walking gears or on other superstructures
  • E02F9/12—Slewing or traversing gears
  • E02F9/121—Turntables, i.e. structure rotatable about 360°
  • E02F9/123—Drives or control devices specially adapted therefor
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2221—Control of flow rate; Load sensing arrangements
  • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
  • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps including an electronic controller
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2221—Control of flow rate; Load sensing arrangements
  • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
  • E02F9/2228—Control of flow rate; Load sensing arrangements using pressure-compensating valves including an electronic controller
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2278—Hydraulic circuits
  • E02F9/2289—Closed circuit
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2278—Hydraulic circuits
  • E02F9/2296—Systems with a variable displacement pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
  • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
  • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
  • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
  • F15B2211/205—Systems with pumps
  • F15B2211/2053—Type of pump
  • F15B2211/20546—Type of pump variable capacity
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/30—Directional control
  • F15B2211/305—Directional control characterised by the type of valves
  • F15B2211/30505—Non-return valves, i.e. check valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/30—Directional control
  • F15B2211/32—Directional control characterised by the type of actuation
  • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/40—Flow control
  • F15B2211/405—Flow control characterised by the type of flow control means or valve
  • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/40—Flow control
  • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
  • F15B2211/41554—Flow control characterised by the connections of the flow control means in the circuit being connected to a return line and a directional control valve
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/40—Flow control
  • F15B2211/455—Control of flow in the feed line, i.e. meter-in control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/50—Pressure control
  • F15B2211/505—Pressure control characterised by the type of pressure control means
  • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
  • F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/50—Pressure control
  • F15B2211/52—Pressure control characterised by the type of actuation
  • F15B2211/528—Pressure control characterised by the type of actuation actuated by fluid pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/6306—Electronic controllers using input signals representing a pressure
  • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/6306—Electronic controllers using input signals representing a pressure
  • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/633—Electronic controllers using input signals representing a state of the prime mover, e.g. torque or rotational speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/63—Electronic controllers
  • F15B2211/6303—Electronic controllers using input signals
  • F15B2211/6346—Electronic controllers using input signals representing a state of input means, e.g. joystick position
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/665—Methods of control using electronic components
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/665—Methods of control using electronic components
  • F15B2211/6652—Control of the pressure source, e.g. control of the swash plate angle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/665—Methods of control using electronic components
  • F15B2211/6653—Pressure control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/665—Methods of control using electronic components
  • F15B2211/6654—Flow rate control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/665—Methods of control using electronic components
  • F15B2211/6655—Power control, e.g. combined pressure and flow rate control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
  • F15B2211/7058—Rotary output members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/755—Control of acceleration or deceleration of the output member

Definitions

• Patent Document 1 describes a technique for controlling the pressure of the pressure oil supplied to the hydraulic motor (output torque of the hydraulic motor) by adjusting the capacity (flow rate) of the hydraulic pump so that the pressure of the hydraulic pump (swing pump) detected by the pressure detection device during the swing drive of the work machine becomes a predetermined target pressure. This technology allows for arbitrary adjustment of the output of the hydraulic motor.
• the present application includes multiple means for solving the above problems.
• One example is as follows.
• the work machine comprises a hydraulic pump that discharges pressure oil, a swing body capable of swing operation, a hydraulic actuator that swing-drives the swing body by supplying pressure oil from the hydraulic pump, an operating device that outputs an operation signal instructing an operation of the swing body, and a speed sensor that detects a driving speed of the hydraulic actuator.
• the work machine further comprises a pressure adjustment device capable of adjusting a driving pressure of the hydraulic actuator, and a controller that controls the pressure adjustment device.
• the controller is configured to calculate a target speed of the hydraulic actuator based on the operation signal from the operating device, calculate a target pressure of the hydraulic actuator based on a speed deviation, which is a difference between the calculated target speed and an actual driving speed of the hydraulic actuator detected by the speed sensor, limit the calculated target pressure so that an input horsepower to the hydraulic actuator does not exceed a limit value, the input horsepower being estimated when it is assumed that the driving pressure of the hydraulic actuator reaches the calculated target pressure after a predetermined time, and control the pressure adjustment device based on the limited target pressure.
• FIG. 1 is an external view showing a hydraulic excavator as an embodiment of the work machine of the present invention.
• the description is given using the direction as seen from the operator seated in the driver's seat.
• the hydraulic excavator includes a self-propelled lower travel body 1 and an upper swing body 2 mounted on the lower travel body 1 in a manner that allows it to swing.
• the lower travel body 1 and the upper swing body 2 together form the body of the hydraulic excavator.
• a front work device 3 for performing excavation work and the like is rotatably attached.
• the front work device 3 is, for example, a multi-jointed work device configured by connecting multiple driven members in a manner that allows them to rotate in the vertical direction.
• the multiple driven members are composed of, for example, a boom 16, an arm 17, and a bucket 18 as a working tool.
• the boom 16, arm 17, and bucket 18 are each driven by hydraulic actuators, namely, a boom cylinder 21, an arm cylinder 22, and a bucket cylinder 23.
• the hydraulic excavator includes a hydraulic system 30 that drives the lower travel body 1, upper swing body 2, and front work device 3 (see FIG. 1 for all) by hydraulic power.
• a hydraulic system 30 that drives the lower travel body 1, upper swing body 2, and front work device 3 (see FIG. 1 for all) by hydraulic power.
• the hydraulic circuit related to the swing hydraulic motor 33 that swing-drives the upper swing body 2 is shown, and the hydraulic circuits related to the travel hydraulic motor 12 that drives the travel device 11 and the boom cylinder 21, arm cylinder 22, and bucket cylinder 23 that drive the front work device 3 are omitted.
• a bleed-off valve 36 is provided on the line 47 branching from the discharge line 44 and connected to the hydraulic oil tank 38.
• the bleed-off valve 36 allows for the adjustment of the discharge pressure of the hydraulic pump 31 according to its degree of opening. That is, the bleed-off valve 36 functions as a pressure adjustment device capable of adjusting the drive pressure of the swing hydraulic motor 33 by releasing the pressure oil discharged from the hydraulic pump 31 to the hydraulic oil tank 38 according to its degree of opening.
• the discharge port of the hydraulic pump 31 is connected to the hydraulic oil tank 38 via a main relief valve 37 .
• the main relief valve 37 defines the upper limit of the discharge pressure of the hydraulic pump 31 and is configured to open when the discharge pressure of the hydraulic pump 31 exceeds the set pressure.
• the first port 33a and the second port 33b of the swing hydraulic motor 33 are connected to the directional control valve 35 via the first line 45 and the second line 46, respectively.
• the first port 33a and the second port 33b of the swing hydraulic motor 33 are connected to the first swing relief valve 39 and the second swing relief valve 40 via the first line 45 and the second line 46, respectively.
• the first swing relief valve 39 and the second swing relief valve 40 open when the pressure in the first line 45 and the second line 46 exceeds the set pressure, respectively, thereby communicating the first line 45 and the second line 46 with the hydraulic oil tank 38, and they serve the overload prevention function of the swing hydraulic motor 33.
• the hydraulic system 30 further includes a joystick 56 as an operating device for instructing the swing operation of the upper swing body 2 or the drive of the swing hydraulic motor 33.
• the joystick 56 outputs an operation signal corresponding to its operation angle to the controller 60.
• the controller 60 acquires the swing operation signal from the joystick 56, the angular velocity detection signal from the speed sensor 54 (the actual angular velocity of the swing hydraulic motor 33 detected by the speed sensor 54), the pressure detection signals from the first pressure sensors 51a and 51b (the pressure on the first port 33a side and the second port 33b side of the swing hydraulic motor 33 detected by the first pressure sensors 51a and 51b), and the discharge pressure detection signal from the second pressure sensor 52 (the discharge pressure of the hydraulic pump 31 detected by the second pressure sensor 52).
• the controller 60 performs predetermined calculations based on these operation signals and detection signals and outputs control signals corresponding to the calculation results to the regulator 31a of the hydraulic pump 31, the directional control valve 35, and the bleed-off valve 36. Details of the calculations will be described later.
• the calculation result (Tt/q) obtained by dividing the target torque Tt by the swing equivalent volume q becomes the target pressure value of the first port 33a, that is, the target meter-in pressure.
• the target pressure of the second port 33b is 0.
• FIG. 6 is a block diagram showing the details of the meter-in pressure limit calculation section 78 in the control block diagram of the controller shown in FIG. 3 .
• the calculation section 781 multiplies the actual angular acceleration (angular acceleration detection value) of the swing hydraulic motor 33 detected by the speed sensor 54 by a reference time (e.g., 0.3 seconds), and the calculation section 782 adds the calculation result of the calculation section 781 to the actual angular velocity (angular velocity detection value) of the swing hydraulic motor 33 detected by the speed sensor 54.
• These calculations estimate the angular velocity of the swing hydraulic motor 33 at a future time after the reference time has elapsed from the current time during the calculation of the controller 60. It is also possible for the controller to perform differential calculations based on the time series of the actual angular velocity (angular velocity detection value) of the swing hydraulic motor 33 detected by the speed sensor 54, and to calculate the actual angular acceleration.
• the target meter-in pressure of the swing hydraulic motor 33 which is the calculation result of the target meter-in pressure calculation section 77, is limited by the meter-in pressure limit value, which is the calculation result of the meter-in pressure limit calculation section 78.
• a horsepower limit target meter-in pressure with a restricted upper limit is calculated.
• these calculations limit the target meter-in pressure so that the estimated input horsepower to the swing hydraulic motor 33 does not exceed the horsepower limit value when it is assumed that the drive pressure of the swing hydraulic motor 33 reaches the target meter-in pressure at a future time after a reference time has elapsed from the current time (after a predetermined time).
• the horsepower limit target meter-in pressure which is the calculation result, is input to the pump flow rate second target value calculation section 79 (see FIG. 7 described later).
• FIG. 7 is a block diagram showing the details of the pump flow rate second target value calculation section 79 in the control block diagram of the controller shown in FIG. 3 .
• the calculation section 791 calculates the pressure deviation by subtracting the actual meter-in pressure of the swing hydraulic motor 33 (the pressure detection value on the meter-in side of the swing hydraulic motor 33) detected by the first pressure sensors 51a, 51b from the input horsepower limit target meter-in pressure.
• the pump flow rate second target value calculation section 79 multiplies the pressure deviation, which is the calculation result of the calculation section 791, by the proportional gain Kp2 in the calculation section 792, and then multiplies it by the integral gain Ki in the calculation section 794 after the integration processing in the calculation section 793. Then, the pump flow rate second target value calculation section 79 adds the calculation results of the calculation sections 793 and 794 in the calculation section 795, and limits the upper and lower bounds of the calculation result of the calculation section 795 using the table 796 to calculate the pump flow rate second target value of the hydraulic pump 31.
• the pump flow rate second target value is derived based on the pressure deviation, which is the difference between the horsepower limit target meter-in pressure and the actual meter-in pressure, and is a control value for performing pressure control of the swing hydraulic motor 33.
• the limitation by the table 796 restricts the pressure, for example, from 0 MPa to the set pressure of the main relief valve 37 of the hydraulic circuit.
• the pump flow rate second target value calculation section 79 outputs the pump flow rate second target value, which is the calculation result, to the pump flow rate control target value calculation section 83 (see FIG. 9 described later).
• the pressure detection values of the first pressure sensors 51a, 51b are input to the calculation section 791 that calculates the pressure deviation, but if the discharge pressure of the hydraulic pump 31 can be considered an approximate value of the meter-in pressure of the swing hydraulic motor 33, it is also possible to input the pressure detection value of the second pressure sensor 52 to the calculation section 791.
• FIG. 8 is a block diagram showing the details of the angular velocity deviation ratio calculation section 81 in the control block diagram of the controller shown in FIG. 3 .
• the calculation section 811 calculates the angular velocity deviation by subtracting the actual angular velocity (angular velocity detection value) of the swing hydraulic motor 33 detected by the speed sensor 54 from the target angular velocity of the swing hydraulic motor 33, which is the calculation result of the target angular velocity calculation section 73.
• FIG. 9 is a block diagram showing the details of the pump flow rate control target value calculation section 83 and the bleed-off opening target value calculation section 85 in the control block diagram of the controller shown in FIG. 3 .
• the pump flow rate control target value calculation section 83 calculates the pump flow rate control target value of the hydraulic pump 31 by adding the pump flow rate first target value, which is the calculation result of the pump flow rate first target value calculation section 74, and the pump flow rate second target value, which is the calculation result of the pump flow rate second target value calculation section 79, according to the ratio determined based on the output value of the table 831.
• the pump flow rate control target value becomes the pump flow rate first target value.
• the pump flow rate control target value becomes the pump flow rate second target value. That is, when the angular velocity deviation ratio is small, for example, when the angular velocity deviation is small and the target angular velocity is high, the controller 60 performs speed control on the swing hydraulic motor 33.
• the bleed-off opening target value calculation section 85 calculates the bleed-off opening target value by referring to the table 851 based on the angular velocity deviation ratio R, which is the calculation result of the angular velocity deviation ratio calculation section 81.
• the table 851 is set to make the opening of the bleed-off valve 36 as small as possible when the angular velocity deviation ratio R is smaller than the first threshold n1. This is to reduce the loss due to the outflow of pressure oil to the hydraulic oil tank 38 through the bleed-off valve 36.
• the table 851 is set to maintain the opening of the bleed-off valve 36 at a predetermined value when the angular velocity deviation ratio is larger than the second threshold n2.
• FIG. 10 is a diagram showing the time waveform of simulation results regarding the behavior of the hydraulic pump and the swing hydraulic motor during swing operation in the work machine of the comparative example for an embodiment of the work machine of the present invention.
• Graph (A) of FIG. 10 shows the time change of the swing operation signal.
• Graph (B) shows the time change of the discharge pressure of the hydraulic pump and the drive pressure of the swing hydraulic motor
• graph (C) shows the time change of the pump flow rate of the hydraulic pump and the motor flow rate of the swing hydraulic motor.
• Graph (D) shows the time change of the angular velocity of the swing hydraulic motor
• graph (E) shows the time change of the angular acceleration of the swing hydraulic motor.
• Graph (F) shows the time change of the output of the hydraulic pump.
• the controller 60 pre-limits the pump target pressure (the product of the estimated flow rate and the pump target pressure) according to the estimated flow rate at a future time (a predetermined time later) after a certain time has elapsed from the current time, through the control calculation shown in FIG. 6 .
• controller 60 of this embodiment controls the closing of the bleed-off valve 36 in response to switching the control target value of the hydraulic pump 31 from pressure control to speed control.
• the controller 60 is configured to limit the calculated target pressure so that the estimated input horsepower to the swing hydraulic motor 33 (hydraulic actuator) does not exceed the limit value when it is assumed that the drive pressure of the swing hydraulic motor 33 (hydraulic actuator) reaches the calculated target pressure after a predetermined time, and to control the regulator 31a and the bleed-off valve 36 (pressure adjustment devices) based on the limited target pressure.
• the controller 60 of the hydraulic excavator is configured to estimate the input horsepower to the swing hydraulic motor 33 (hydraulic actuator) at a future time (a predetermined time later) by estimating the angular velocity (drive speed) of the swing hydraulic motor 33 (hydraulic actuator) at a future time (a predetermined time later) based on the actual angular velocity and actual angular acceleration of the swing hydraulic motor 33 (hydraulic actuator) obtained from the detection values of the speed sensor 54.
• This configuration allows for easy and accurate estimation of the drive speed of the swing hydraulic motor 33 (hydraulic actuator) at a future time (a predetermined time later) by using the actual drive speed and actual drive acceleration of the swing hydraulic motor 33 (hydraulic actuator) obtained from the speed sensor 54. Therefore, it becomes possible to correctly limit the calculated target pressure so that the estimated input horsepower to the swing hydraulic motor 33 (hydraulic actuator), obtained from the integration of the estimated flow rate calculated from the estimated drive speed at a future time (a predetermined time later) and the target pressure of the swing hydraulic motor 33 (hydraulic actuator), does not exceed the horsepower limit value. As a result, the swing hydraulic motor 33 (hydraulic actuator) can be driven with smooth acceleration without exceeding the horsepower limit value.
• the pressure adjustment device includes a regulator 31a as a flow adjustment device capable of adjusting the drive pressure of the swing hydraulic motor 33 (hydraulic actuator) by adjusting the discharge flow rate of the hydraulic pump 31.
• the controller 60 calculates the first target value of the pump flow rate of the hydraulic pump 31 based on the calculated target speed, and calculates the second target value of the pump flow rate of the hydraulic pump 31 based on the limited target pressure. Additionally, the controller 60 calculates the speed deviation ratio, which is the ratio of the speed deviation to the calculated target speed, and executes control of the regulator 31a (flow adjustment device) based on the first target value of the pump flow rate when the calculated speed deviation ratio is smaller than the first threshold n1.
• the controller 60 executes control of the regulator 31a (flow adjustment device) based on the second target value of the pump flow rate of the calculation result, as control of the pressure adjustment device based on the restricted target pressure.
• the pressure adjustment device further includes a bleed-off valve 36 that releases the pressure oil discharged from the hydraulic pump 31 to the hydraulic oil tank 38.
• the controller 60 executes the control of the regulator 31a (flow adjustment device) based on the first target value of the pump flow rate from the calculation result, it simultaneously controls the bleed-off valve 36 to a closed state, whereas when executing control based on the second target value of the pump flow rate, it simultaneously controls the bleed-off valve 36 to maintain a predetermined opening degree.
• the present invention is not limited to the above-described embodiment and includes various modifications.
• the above-described embodiments have been detailed to clearly explain the present invention and are not necessarily limited to including all the configurations described. For example, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Additionally, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.
• a regulator 31a as a flow adjustment device capable of adjusting the discharge flow rate of the hydraulic pump 31, and a bleed-off valve 36 to release the pressure oil discharged from the hydraulic pump 31 to the hydraulic oil tank 38, as a pressure adjustment device capable of adjusting the driving pressure of the swing hydraulic motor 33.
• the hydraulic pump is of a fixed displacement type, it is also possible to adjust the driving pressure of the swing hydraulic motor 33 by controlling the discharge flow rate of the hydraulic pump by changing the rotational speed of the prime mover 32.
• the prime mover 32 functions as a flow adjustment device capable of adjusting the discharge flow rate of the hydraulic pump by adjusting its rotational speed, and by adjusting the discharge flow rate of the hydraulic pump, it functions as a pressure adjustment device capable of adjusting the driving pressure of the swing hydraulic motor 33.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mining & Mineral Resources (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Mechanical Engineering (AREA)
• Fluid-Pressure Circuits (AREA)
• Operation Control Of Excavators (AREA)

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• 2023
  • 2023-09-29 EP EP23872608.7A patent/EP4585808A1/fr active Pending
  • 2023-09-29 JP JP2024550500A patent/JPWO2024071389A1/ja active Pending
  • 2023-09-29 CN CN202380065152.7A patent/CN119855992B/zh active Active
  • 2023-09-29 WO PCT/JP2023/035674 patent/WO2024071389A1/fr not_active Ceased
  • 2023-09-29 KR KR1020257008024A patent/KR20250049552A/ko active Pending

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