JP6933621B2 - Construction machinery - Google Patents

Description

The present invention relates to construction machinery such as hydraulic excavators.

A hydraulic excavator as a construction machine includes a swivel body provided so as to be swivelable on a traveling body. In addition to this, the hydraulic excavator is provided between the hydraulic motor as a drive source of the swivel body, the hydraulic pump that supplies pressure oil to the hydraulic motor, and the swivel lever device provided between the hydraulic motor and the hydraulic pump. It is equipped with a control valve that controls the flow of pressure oil supplied from the hydraulic pump to the hydraulic motor.

Further, in Patent Document 1, when the discharge pressure of the hydraulic pump rises above a predetermined pressure in the case of turning acceleration, turning deceleration, or stopping, the discharge flow rate of the hydraulic pump is set by the characteristic for controlling horsepower. A configuration that reduces the flow rate is disclosed. As a result, in the construction machine described in Patent Document 1, the relief loss can be reduced.

Japanese Unexamined Patent Publication No. 2015-75171

By the way, in the prior art described in Patent Document 1, in the case of turning acceleration, the turning speed is controlled by the meter-in throttle, the meter-out throttle, and the bleed-off throttle of the control valve in addition to the discharge flow rate of the hydraulic pump. Therefore, there is a problem that a loss occurs depending on each throttle of the control valve.

Further, when turning decelerating or stopping, a lever operation in the direction opposite to the turning direction may be performed to generate a brake pressure. Also in this case, in addition to the discharge flow rate of the hydraulic pump, the pressure is controlled by the meter-in throttle, the meter-out throttle, and the bleed-off throttle of the control valve. Therefore, there is a problem that a loss occurs depending on each throttle of the control valve.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a construction machine capable of reducing the loss due to the control valve.

In order to solve the above-mentioned problems, the present invention has a hydraulic motor that swivels and drives a swivel body, supplies pressure oil to the hydraulic motor driven by a prime mover, and uses a regulator to control horsepower within the range of horsepower characteristics of the prime mover. A variable displacement hydraulic pump whose discharge flow rate is controlled, and a pressure oil supplied from the hydraulic pump to the hydraulic motor in response to a turning command, which is provided by connecting between the hydraulic pump and the hydraulic pump. A control valve that controls the flow rate and direction, a swivel lever device that outputs the swivel command according to the amount of operation, a swivel direction detector that detects the swivel direction of the swivel body, the hydraulic pump, and the control valve. Applies to construction machines equipped with a controlling controller.

Then, the feature of the present invention is that when the discharge pressure of the hydraulic pump becomes equal to or higher than a predetermined pressure, the controller reduces the discharge flow rate of the hydraulic pump from the flow rate set by the horsepower control and turns. When the swivel command is output from the swivel lever device in the stopped state, or the swivel direction according to the swivel command output from the swivel lever device and the swivel body detected by the swivel direction detector. If the turning direction is the same, it is determined to be an acceleration operation, and if the turning direction in response to the turning command is different from the turning direction of the swivel body, it is determined to be a reverse lever operation, and it is determined to be the acceleration operation or the reverse lever operation. In this case, when the operating amount of the swivel lever device exceeds a predetermined value, the control valve is controlled to be switched to the fully open position, and the swivel speed of the swivel body is based on the discharge flow rate of the hydraulic pump. And the brake pressure of the hydraulic motor are controlled, and when it is determined that the operation is different from both the acceleration operation and the reverse lever operation, the control valve is set according to the operation amount of the turning lever device. The purpose is to control the opening degree, and to control the turning speed of the swinging body and the braking pressure of the hydraulic motor based on the valve opening degree of the control valve and the discharge flow rate of the hydraulic pump.

According to the present invention, the loss due to the control valve can be reduced.

It is a front view which shows the hydraulic excavator by embodiment of this invention. It is a hydraulic circuit diagram which shows the circuit structure which drives the hydraulic motor for turning by embodiment. It is explanatory drawing which shows the relationship between the turning operation determination, the operation state of the turning lever device, and the turning operation determination result. It is a characteristic diagram which shows the characteristic map by the 1st and 2nd control valve table. It is a characteristic diagram which shows the characteristic map by the table for a hydraulic pump. It is a characteristic diagram which shows the PQ characteristic map of a hydraulic pump. It is a flow chart which shows operation state determination processing. It is a flow chart which follows FIG.

Hereinafter, a hydraulic excavator will be taken as an example of a construction machine according to an embodiment of the present invention, and will be described in detail with reference to the accompanying drawings.

In FIG. 1, the hydraulic excavator 1, which is a typical example of a construction machine, is used for excavation work of earth and sand. The hydraulic excavator 1 according to the embodiment is a super-large back-hoe type hydraulic excavator. The hydraulic excavator 1 includes a self-propelled crawler-type lower traveling body 2, an upper swivel body 3 provided so as to be swivel on the lower traveling body 2, and an operation (rotation) of elevation on the front side of the upper swivel body 3. It is configured to include a working device (front) 9 that is possibly attached. The lower traveling body 2 and the upper turning body 3 form a vehicle body (base). The lower traveling body 2 includes a hydraulic motor 2A for performing a traveling operation.

The upper swivel body 3 (swivel body) is swiveled and driven with respect to the lower traveling body 2 by the swivel device 4. The upper swivel body 3 is attached to the lower traveling body 2 via the swivel device 4. The swivel device 4 includes a hydraulic motor 4A that swivels and drives the upper swivel body 3. The upper swivel body 3 has a swivel frame 5 having a support structure and a work device 9 mounted on the front side in the front-rear direction, a cab 6 mounted on the left front side of the swivel frame 5 to form a driver's cab, and a rear of the cab 6. The building cover 7 that is located on the side and houses the engine 22, the hydraulic pump 23, the pilot pump 26, the control valve 32 (see FIG. 2), etc. mounted on the swivel frame 5 and the work that is attached to the rear side of the swivel frame 5 It is configured to include a counter weight 8 that balances the weight with the device 9.

Here, inside the cab 6, a driver's seat (not shown) on which the operator sits is provided. A traveling lever / pedal device and a working lever device are provided around the driver's seat. The traveling lever / pedal device is operated by the operator in order to travel the lower traveling body 2. The work lever device is operated by an operator in order to rotate the upper swing body 3 and the work device 9.

Note that FIG. 2 shows a turning lever device 35 as a working lever device. The swivel lever device 35 switches the control valve 32 in order to swivel the upper swivel body 3 to the right or to the left.

The working device 9 is a front actuator mechanism. The working device 9 is composed of, for example, a boom 10, an arm 11, a bucket 12, and a boom cylinder 13, an arm cylinder 14, and a bucket cylinder 15 that drive them. The working device 9 is attached to the swivel frame 5 of the upper swivel body 3.

The boom cylinder 13, the arm cylinder 14, and the bucket cylinder 15 change the posture of the working device 9 by expanding or contracting based on the pressure oil from the hydraulic pump 23. That is, during excavation work of earth and sand, the boom cylinder 13, the arm cylinder 14, and the bucket cylinder 15 are expanded or contracted based on the lever operation of the work lever device, and the boom 10 and the arm 11 are rotated while rotating the boom 10 and the arm 11. Rotate the bucket 12. As a result, earth and sand can be excavated on the tip side of the bucket 12.

Next, the hydraulic circuit 21 for driving the turning hydraulic motor 4A will be described with reference to FIG.

The hydraulic circuit 21 is for driving the turning hydraulic motor 4A. The hydraulic circuit 21 includes an engine 22, a hydraulic pump 23, a tank 25, a pilot pump 26, a control valve 32, a swivel lever device 35, a controller 45, and the like, in addition to the hydraulic motor 4A.

The engine 22 is located between the cab 6 and the counterweight 8 and is provided on the swivel frame 5. The engine 22 is composed of, for example, a diesel engine, and is a prime mover for rotationally driving the hydraulic pump 23 and the pilot pump 26.

The hydraulic pump 23 is mounted on the swivel frame 5 of the upper swivel body 3. The hydraulic pump 23 is driven by the engine 22. The hydraulic pump 23 constitutes a main hydraulic source together with a tank 25 for storing hydraulic oil. On the other hand, the pilot pump 26 is also rotationally driven by the engine 22. The pilot pump 26, together with the tank 25, constitutes a pilot hydraulic source. The hydraulic pump 23 discharges pressure oil to the discharge pipe line (delivery pipe line) 27. A relief valve 28 is connected to the discharge pipe line 27. The relief valve 28 opens when the pressure exceeds a preset pressure, and allows the hydraulic oil to escape to the tank 25. The discharge pipe line 27 branches to the center bypass pipe line 29 and the branch line line 30 on the upstream side of the control valve 32. The pilot pump 26 discharges pilot pressure oil to the pilot pipeline 31.

The hydraulic pump 23 supplies pressure oil to the boom cylinder 13, the arm cylinder 14, the bucket cylinder 15, the traveling hydraulic motor 2A of the lower traveling body 2, and the turning hydraulic motor 4A of the turning device 4. That is, the hydraulic pump 23 sucks hydraulic oil (oil) from the tank 25 by being driven by the engine 22, and supplies (discharges) the sucked hydraulic oil to the control valve 32 as pressure oil. Note that FIG. 2 shows only the control valve 32 that controls the supply and discharge of pressure oil to the turning hydraulic motor 4A.

The hydraulic pump 23 is, for example, a slanted plate type, a radial piston type, or a slanted shaft type variable displacement hydraulic pump. That is, the hydraulic pump 23 can variably adjust the push-out volume. Therefore, the hydraulic pump 23 has a capacity variable portion 23A made of a swash plate, a swash plate, or the like. The capacitance variable portion 23A is driven (tilted drive) by the regulator 24. The regulator 24 drives (tilt drive) the capacitance variable unit 23A based on the command of the controller 45. As a result, the pump capacity (pushing volume) of the hydraulic pump 23 can be increased or decreased, and the discharge flow rate of the pressure oil can be increased or decreased according to the tilt angle. Further, in the hydraulic pump 23, the discharge flow rate is controlled within the range of the horsepower characteristic of the engine 22 by the regulator 24 as the horsepower control.

The control valve 32 is provided so as to be connected between the hydraulic pump 23 and the hydraulic motor 4A. The control valve 32 is provided in the middle of the center bypass line 29 that connects the discharge line 27 of the hydraulic pump 23 to the tank 25. The control valve 32 switches and controls the direction of the pressure oil supplied from the hydraulic pump 23 to the hydraulic motor 4A. That is, the control valve 32 controls the supply and discharge of pressure oil to the hydraulic motor 4A.

The control valve 32 is composed of, for example, a hydraulic pilot type directional control valve at 6 ports and 3 positions. The control valve 32 is connected to the hydraulic pump 23 via the discharge pipe line 27, and is connected to the tank 25 via the center bypass pipe line 29 and the return pipe line 33.

The control valve 32 is operated (switching operation) by the turning lever device 35. The control valve 32 controls the flow rate and direction of the pressure oil supplied from the hydraulic pump 23 to the hydraulic motor 4A in response to the swivel command output from the swivel lever device 35. A pair of hydraulic pilot portions 32A and 32B are provided on both ends of the control valve 32. Pilot pressure (switching signal) based on the operation of the turning lever device 35 is supplied to the hydraulic pilot units 32A and 32B.

In the control valve 32, a pair of inflow and outflow ports are connected to the turning hydraulic motor 4A via the main pipelines 34A and 34B. Here, the control valve 32 is switched from the neutral position (I) shown in FIG. 2 when the pilot pressure is supplied to either one of the hydraulic pilot units 32A and 32B by the tilting operation of the turning lever device 35. It can be switched to either (II) or (III). As a result, the swivel hydraulic motor 4A is rotationally driven in the forward or reverse direction by the pressure oil supplied from the hydraulic pump 23, and the upper swivel body 3 is swiveled to the left or right on the lower traveling body 2. Let me.

The swivel lever device 35 is a swivel lever device as an operating device for switching and operating the control valve 32. The turning lever device 35 is tilted by an operator when the turning hydraulic motor 4A is rotationally driven. The turning lever device 35 outputs a turning command according to the amount of operation to the controller 45. The controller 45 controls the proportional electromagnetic pressure reducing valves 48 and 49 in response to a swivel command from the swivel lever device 35. As a result, the pilot pressure corresponding to the operation amount of the turning lever device 35 is supplied to the hydraulic pilot units 32A and 32B of the control valve 32.

The relief valves 36 and 37 are located between the hydraulic motor 4A and the control valve 32 and are connected in the middle of the main pipelines 34A and 34B. The relief valves 36 and 37 open when the pressure exceeds a preset pressure, and allow the hydraulic oil to escape.

The check valves 38 and 39 are located between the hydraulic motor 4A and the control valve 32 and are connected in the middle of the main pipelines 34A and 34B. The check valves 38 and 39 are connected to the tank 25 via the tank line 40. When any of the main pipelines 34A and 34B becomes negative pressure during the inertial rotation of the hydraulic motor 4A, the check valves 38 and 39 replenish the hydraulic oil in the tank 25 into the main pipelines 34A and 34B.

The turning angular velocity sensor 41 is attached to the turning device 4. The turning angular velocity sensor 41 detects the turning direction of the upper swing body 3. Specifically, the turning angular velocity sensor 41 detects whether the turning operation state is turning stop, right turning, or left turning. The detection signal from the turning angular velocity sensor 41 is output to the controller 45.

The pressure sensor 42 is a pressure detector that detects the pressure in the main pipeline 34A. The pressure sensor 42 is connected to the main pipeline 34A and detects the pressure in the main pipeline 34A. The detection signal from the pressure sensor 42 is output to the controller 45.

The pressure sensor 43 is a pressure detector that detects the pressure in the main pipeline 34B. The pressure sensor 43 is connected to the main pipeline 34B and detects the pressure in the main pipeline 34B. The detection signal from the pressure sensor 43 is output to the controller 45.

The pressure sensor 44 is a pressure detector that detects the discharge pressure of the hydraulic pump 23. The pressure sensor 44 is connected to the discharge pipe line 27 between the hydraulic pump 23 and the control valve 32, for example, and detects the pressure in the discharge pipe line 27. The detection signal from the pressure sensor 44 is output to the controller 45.

The controller 45 is a control device configured by, for example, a microcomputer. The controller 45 controls the hydraulic pump 23 and the control valve 32. Specifically, the controller 45 controls the capacity of the hydraulic pump 23 (for example, positive control) and also controls the switching of the control valve 32.

The input side of the controller 45 is connected to a swivel lever device 35, a swivel angular velocity sensor 41, and pressure sensors 42 to 44. For example, proportional electromagnetic pressure reducing valves 48 and 49 and a regulator 24 are connected to the output side of the controller 45. The regulator 24 drives the capacity variable unit 23A according to the control signal output from the controller 45, and variably controls the discharge flow rate of the pressure oil by the hydraulic pump 23 by so-called positive control. At this time, when the discharge pressure of the hydraulic pump 23 becomes equal to or higher than a preset predetermined pressure (cutoff pressure Pc), the controller 45 sets the discharge flow rate of the hydraulic pump 23 to be higher than the flow rate set by horsepower control. The pump capacity control unit 46 for reducing is provided.

The controller 45 has a memory 45A including a ROM, a RAM, a non-volatile memory, and the like. In the memory 45A, the characteristic map by the first and second control valve tables shown in FIG. 4, the characteristic map by the hydraulic pump table shown in FIG. 5, and the discharge pressure P and the discharge of the hydraulic pump 23 shown in FIG. The PQ characteristic map that stores the relationship (PQ characteristic) with the capacity Q (flow rate) and the operation state determination processing program shown in FIGS. 7 and 8 are stored.

The controller 45 turns upward when a turning command is output from the turning lever device 35 in the turning stopped state, or when the turning direction and turning angular velocity sensor 41 are detected according to the turning command output from the turning lever device 35. When the turning direction of the body 3 is the same, it is determined that the operation is acceleration, and when the turning direction according to the turning command and the turning direction of the upper turning body 3 are different, it is determined that the operation is a reverse lever. That is, as shown in FIG. 3, the controller 45 (determination unit 47) performs an acceleration operation, a reverse lever operation, and a stop operation based on the current determination result of the turning operation and the operating state of the turning lever device 35. Determine which operating state it is in.

When performing the stop operation, the determination unit 47 determines that the operation is different from both the acceleration operation and the reverse lever operation. In this case, the controller 45 controls the control valve 32 based on the first control valve table, for example, as shown by the characteristic line 100 shown by the solid line in FIG. Specifically, when the stop operation is performed, the controller 45 controls the displacement amount of the spool of the control valve 32 based on the lever angle of the turning lever device 35 so as to have the characteristics shown in the characteristic line 100. In the characteristic line 100, the relationship between the lever angle (operation amount) of the swivel lever device 35 and the displacement amount of the spool of the control valve 32 increases as the lever angle increases between the displacement amounts S1 to S3, and the spool of the control valve 32. The displacement amount of the spool increases at a constant rate (that is, the spool displacement amount increases or decreases in proportion to the lever angle). The characteristic line 100 is a displacement of the spool over a fine operation range (less than a preset predetermined value α) in which the lever angle (operation amount) is larger than the fine operation range and a half to full operation range (predetermined value α or more) larger than the fine operation range. It has a characteristic that the amount increases at a constant rate between the displacement amounts S1 to S3. At this time, the fine operation area is, for example, a region where the minimum pressure oil flows through the hydraulic motor 4A and fine operation is possible. The half to full operation range is a region in which a large amount of pressure oil flows through the hydraulic motor 4A as compared with the fine operation range.

When performing the acceleration operation, the determination unit 47 determines that the acceleration operation is performed. When performing the reverse lever operation, the determination unit 47 determines that the reverse lever operation is performed. In any of these cases, the controller 45 controls the control valve 32 based on the second control valve table, for example, as shown by the characteristic line 101 shown by the broken line in FIG. Specifically, when the acceleration operation or the reverse lever operation is performed, the controller 45 determines the displacement amount of the spool of the control valve 32 based on the lever angle of the turning lever device 35 so as to have the characteristics shown in the characteristic line 101. Control. The characteristic line 101 has a characteristic that the displacement amount of the spool increases at the same rate as the characteristic line 100 between the displacement amounts S1 to S2 when the lever angle (operation amount) of the turning lever device 35 is in the fine operation range. ing. The characteristic line 101 shows the maximum value (displacement amount Sm) of the spool of the control valve 32 reaching the stroke end when the lever angle of the turning lever device 35 is in the half to full operation range larger than the fine operation range. It has a constant characteristic.

Further, the controller 45 capacity-controls the hydraulic pump 23 based on the hydraulic pump table, for example, as shown by the characteristic line 102 shown by the solid line in FIG. Specifically, the controller 45 outputs a control signal to the regulator 24 so as to have the characteristics shown in the characteristic line 102. As a result, the discharge flow rate (pump flow rate) of the hydraulic pump 23 is controlled based on the lever angle of the swivel lever device 35. In the characteristic line 102, the relationship between the lever angle of the swivel lever device 35 and the discharge flow rate (pump flow rate) of the hydraulic pump 23 is such that the operation amount of the swivel lever device 35 is from zero to the middle of the fine operation range (range). Occasionally, the pump flow rate has a characteristic of being a constant value (flow rate Qa). In the characteristic line 102, when the lever angle becomes larger than in the middle of the fine operation range, the discharge flow rate of the hydraulic pump 23 increases at a constant rate as the operation amount of the swivel lever device 35 increases over the half to full operation range. The characteristic is that the pump flow rate increases to ~ Qb (that is, the pump flow rate increases / decreases in proportion to the lever angle between the flow rates Qa to Qb).

Further, the controller 45 uses the regulator 24 to make the relationship between the discharge pressure P (pump pressure) of the hydraulic pump 23 and the discharge flow rate Q a PQ characteristic based on the horsepower curve of the engine 22. Capacity control. As for the PQ characteristics, when the discharge pressure P is less than the horsepower control start pressure Ph, the tilt angle is set to the maximum value, and when the discharge pressure P becomes the horsepower control start pressure Ph or more, the hydraulic pump 23 responds to the increase in the discharge pressure P. This is a characteristic that reduces the discharge flow rate Q.

At this time, the controller 45 capacity-controls the hydraulic pump 23 based on the hydraulic pump table, for example, as shown by the characteristic line 103 shown by the solid line in FIG. Specifically, the controller 45 outputs a control signal to the regulator 24 so as to have the characteristics shown in the characteristic line 103. As a result, the discharge flow rate Q (pump flow rate) of the hydraulic pump 23 is controlled based on the discharge pressure P of the hydraulic pump 23. The characteristic line 103 has a characteristic that the discharge flow rate Q becomes the maximum value Qmax when the discharge pressure P is within the range of 0 or more and less than the horsepower control start pressure Ph. The characteristic line 103 has a characteristic that when the discharge pressure P becomes equal to or higher than the horsepower control start pressure Ph, the discharge flow rate Q decreases as the discharge pressure P increases. The characteristic line 103 has a characteristic that the discharge flow rate Q becomes the minimum value Qmin when the discharge pressure P rises above the horsepower control start pressure Ph and becomes the cutoff pressure Pc or more.

In this way, when the discharge pressure P of the hydraulic pump 23 becomes equal to or higher than the cutoff pressure Pc, the controller 45 sets the discharge flow rate Q of the hydraulic pump 23 to the characteristic line 104 (broken line in FIG. 6) for controlling horsepower. The flow rate is reduced from the flow rate set by the indicated characteristic (PQ characteristic).

The proportional electromagnetic pressure reducing valves 48 and 49 are connected between the pilot pump 26 and the hydraulic pilot portions 32A and 32B of the control valve 32. The proportional electromagnetic pressure reducing valves 48 and 49 electromagnetically and proportionally control the pilot pressure supplied to the hydraulic pilot units 32A and 32B according to the control signal output from the controller 45.

That is, the proportional electromagnetic pressure reducing valve 48 for turning right and the proportional electromagnetic pressure reducing valve 49 for turning left hold the control valve 32 in the neutral position (I) in a demagnetized state until it is excited by the control signal. As a result, the pilot pressure supplied to the hydraulic pilot units 32A and 32B of the control valve 32 is maintained in a low pressure state. However, when excited by the control signal, the proportional electromagnetic pressure reducing valve 48 for turning right supplies the pilot pressure supplied to the hydraulic pilot unit 32A on one side (turning right) of the control valve 32 to the current value of the control signal. It is variably controlled in proportion to. The proportional electromagnetic pressure reducing valve 49 for left turning proportional to the current value of the control signal the pilot pressure supplied to the hydraulic pilot unit 32B on the other side (left turning) of the control valve 32 when excited by the control signal. And variably control.

Next, the operation state determination process by the controller 45 will be described with reference to FIGS. 7 and 8.

In step S1, the controller 45 determines whether or not it is in the turning stop state based on the detection signal from the turning angular velocity sensor 41. In the turning stop state, it is determined as "YES" in step S1 and the process proceeds to step S11. In the right-turning state or the left-turning state, "NO" is determined in step S1 and the process proceeds to step S2.

In step S2, the controller 45 determines whether or not the right turning operation is in progress based on the detection signal from the turning angular velocity sensor 41. When the right turning operation is in progress, it is determined as "YES" in step S2, and the process proceeds to step S16. When it is not in the right turn operation, that is, when it is in the left turn operation, it is determined as "NO" in step S2, and the process proceeds to step S3.

In step S3, the controller 45 determines whether or not the right turning operation is in progress based on the turning command output from the turning lever device 35. When the right turn operation is in progress, it is determined as "YES" in step S3, and the process proceeds to step S6. In step S6, since the right turn operation is performed during the left turn operation, the controller 45 determines that it is in the reverse lever operation state, and proceeds to step S8.

When the right turn operation is not in progress, it is determined as "NO" in step S3, and the process proceeds to step S4. In step S4, the controller 45 determines whether or not the left turning operation is in progress based on the turning command output from the turning lever device 35. When the left turn operation is in progress, it is determined as "YES" in step S4, and the process proceeds to step S7. In step S7, since the left turn operation is performed during the left turn operation, the controller 45 determines that it is in the acceleration operation state, and proceeds to step S8.

When neither the right turning operation nor the left turning operation is in progress, that is, when the turning lever device 35 is in the neutral position and the stop operation is in progress, it is determined as "NO" in step S4, and the process proceeds to step S5. In step S5, the controller 45 determines that it is in the stop operation state, and proceeds to step S8.

In step S11, the controller 45 determines whether or not the right turning operation is in progress based on the turning command output from the turning lever device 35. When the right turn operation is in progress, it is determined as "YES" in step S11, and the process proceeds to step S15. In step S15, since the right turn operation is performed in the turn stop state, the controller 45 determines that it is in the acceleration operation state, and proceeds to step S8.

When the right turn operation is not in progress, it is determined as "NO" in step S11, and the process proceeds to step S12. In step S12, the controller 45 determines whether or not the left turning operation is in progress based on the turning command output from the turning lever device 35. When the left turn operation is in progress, it is determined as "YES" in step S12, and the process proceeds to step S14. In step S14, since the left turn operation is performed in the turn stop state, the controller 45 determines that it is in the acceleration operation state, and proceeds to step S8.

When neither the right turning operation nor the left turning operation is being performed, that is, when the turning lever device 35 is in the neutral position and the stop operation is in progress, it is determined as "NO" in step S12, and the process proceeds to step S13. In step S13, the controller 45 determines that it is in the stop operation state, and proceeds to step S8.

In step S16, the controller 45 determines whether or not the right turning operation is in progress based on the turning command output from the turning lever device 35. When the right turn operation is in progress, it is determined as "YES" in step S16, and the process proceeds to step S20. In step S20, since the right turn operation is performed during the right turn operation, it is determined that the acceleration operation state is in effect, and the process proceeds to step S8.

When the right turning operation is not in progress, it is determined as "NO" in step S16, and the process proceeds to step S17. In step S17, the controller 45 determines whether or not the left turning operation is in progress based on the turning command output from the turning lever device 35. When the left turn operation is in progress, it is determined as "YES" in step S17, and the process proceeds to step S19. In step S19, since the left turn operation is performed during the right turn operation, the controller 45 determines that the reverse lever operation state is in effect, and proceeds to step S8.

When neither the right turning operation nor the left turning operation is being performed, that is, when the turning lever device 35 is in the neutral position and the stop operation is in progress, a determination of "NO" is made in step S17, and the process proceeds to step S18. In step S18, the controller 45 determines that it is in the stop operation state, and proceeds to step S8.

In step S8, the controller 45 determines whether or not it is in the acceleration operation state or the reverse lever operation state. When it is in the acceleration operation state or the reverse lever operation state, it is determined as "YES" in step S8, and the process proceeds to step S10. In step S10, the controller 45 controls the control valve 32 based on the second control valve table shown in the characteristic line 101 in FIG. 4 as the control process without throttle. As a result, in the acceleration operation state or the reverse lever operation state, the turning speed and the brake pressure are controlled as follows in the fine operation range and the half to full operation range.

In the fine operation range, the flow rate of the hydraulic oil supplied or discharged from the turning hydraulic motor 4A is determined according to the pump discharge flow rate determined according to the characteristic line 102 in FIG. 5 and the characteristic line 101 shown in FIG. It is determined by the throttle amount (meter-in throttle amount, meter-out throttle amount, bleed-off throttle amount) according to the displacement amount of the spool of the control valve 32. At this time, the turning speed is controlled according to the flow rate of the hydraulic oil. In addition to this, when the discharge pressure P of the hydraulic pump 23 reaches a predetermined pressure (cutoff pressure Pc), the pump discharge flow rate decreases according to the characteristic line 103 in FIG. As a result, the flow rate of the hydraulic oil discharged from the relief valve 28 is reduced, and the energy loss can be reduced.

In the half to full operation range, the control valve 32 operates the spool up to the maximum displacement position (displacement amount Sm) according to the characteristic line 101 shown in FIG. 4, and the state is maintained. Therefore, the flow rate of the hydraulic oil supplied or discharged from the turning hydraulic motor 4A is determined by the pump discharge flow rate determined according to the characteristic line 102 in FIG. At this time, the turning speed is controlled according to the flow rate of the hydraulic oil. In addition to this, when the discharge pressure P of the hydraulic pump 23 reaches a predetermined pressure (cutoff pressure Pc), the pump discharge flow rate decreases according to the characteristic line 103 in FIG. As a result, the flow rate of the hydraulic oil discharged from the relief valve 28 is reduced, and the energy loss can be reduced.

When it is neither the acceleration operation state nor the reverse lever operation state, that is, when it is in the stop operation state, it is determined as "NO" in step S8, and the process proceeds to step S9. In step S9, the control valve 32 is controlled based on the first control valve table shown in the characteristic line 100 in FIG. 4 as the control process with throttle. As a result, in the stop operation state, the turning speed and the brake pressure are controlled as follows in the fine operation range and the half to full operation range.

In the fine operation range and the half to full operation range, the flow rates of the hydraulic oil supplied or discharged from the turning hydraulic motor 4A are shown in FIG. 4 and the pump discharge flow rate determined according to the characteristic line 102 in FIG. It is determined by the throttle amount (meter-in throttle amount, meter-out throttle amount, bleed-off throttle amount) according to the displacement amount of the spool of the control valve 32 determined according to the characteristic line 100. At this time, the turning speed is controlled according to the flow rate of the hydraulic oil. In addition to this, when the discharge pressure P of the hydraulic pump 23 reaches a predetermined pressure (cutoff pressure Pc), the pump discharge flow rate decreases according to the characteristic line 103 in FIG. As a result, the flow rate of the hydraulic oil discharged from the relief valve 28 is reduced, and the energy loss can be reduced.

Thus, according to the present embodiment, the controller 45 sets the discharge flow rate Q of the hydraulic pump 23 by horsepower control when the discharge pressure P of the hydraulic pump 23 becomes equal to or higher than a predetermined pressure (cutoff pressure Pc). The flow rate is reduced. Further, the controller 45 has a turning direction and a turning angular velocity sensor 41 (swivel direction detection) when a turning command is output from the turning lever device 35 in the turning stopped state or in response to the turning command output from the turning lever device 35. If the turning direction of the upper swivel body 3 (swivel body) detected by the instrument) is the same, it is determined that the acceleration operation is performed, and if the turning direction according to the turning command and the turning direction of the upper swivel body 3 are different, the reverse lever is used. Judge as an operation.

Then, when the controller 45 determines that the acceleration operation or the reverse lever operation is performed, the control valve 32 is fully opened when the operation amount of the turning lever device 35 exceeds a predetermined value α (half to full operation range). The turning speed of the upper swing body 3 and the brake pressure of the hydraulic motor 4A are controlled based on the discharge flow rate Q of the hydraulic pump 23.

That is, when the discharge pressure P of the hydraulic pump 23 tends to increase as in the acceleration operation or the reverse lever operation, when the operation amount of the turning lever device 35 exceeds the predetermined value α (half to full operation range). ), The control valve 32 is switched to the fully open position. As a result, it is possible to reduce the loss due to the throttle amount according to the displacement amount of the spool of the control valve 32.

Further, when the controller 45 determines that the operation is different from both the acceleration operation and the reverse lever operation, the control valve 32 of the spool is set to have a valve opening degree according to the operation amount of the turning lever device 35. The amount of displacement is controlled, and the swing speed of the upper swing body 3 and the brake pressure of the hydraulic motor 4A are controlled based on the valve opening degree of the control valve 32 and the discharge flow rate of the hydraulic pump 23.

That is, when the increase in the discharge pressure P of the hydraulic pump 23 is suppressed as in the stop operation, the control valve 32 is controlled so that the valve opening degree corresponds to the operation amount of the swivel lever device 35. At this time, the flow rate of the hydraulic oil supplied or discharged from the turning hydraulic motor 4A is a throttle amount (meter-in) according to the discharge flow rate Q of the hydraulic pump 23 and the displacement amount (valve opening) of the spool of the control valve 32. It is determined by the aperture amount, meter-out aperture amount, bleed-off aperture amount). Thereby, the turning speed can be controlled according to the flow rate of the hydraulic oil at this time.

Further, when the controller 45 determines that the acceleration operation or the reverse lever operation is performed and the operation amount of the swivel lever device 35 is smaller than the predetermined value α, the control valve 32 is set to the operation amount of the swivel lever device 35. The valve opening degree is controlled according to the valve opening degree, and the turning speed of the upper swinging body 3 and the brake pressure of the hydraulic motor 4A are controlled based on the valve opening degree of the control valve 32 and the discharge flow rate of the hydraulic pump 23.

That is, even when it is determined that the acceleration operation or the reverse lever operation is performed, when the operation amount of the swivel lever device 35 is smaller than the predetermined value α, the discharge flow rate Q of the hydraulic pump 23 is small and the discharge pressure of the hydraulic pump 23. P tends to be low. At this time, since the pressure loss based on the throttle amount according to the displacement amount of the spool of the control valve 32 tends to be small, the controller 45 is based on the valve opening degree of the control valve 32 and the discharge flow rate Q of the hydraulic pump 23. , The turning speed of the upper swing body 3 and the braking pressure of the hydraulic motor 4A are controlled.

Further, the controller 45 controls the hydraulic pump 23 by using the regulator 24 so that the discharge flow rate corresponds to the operation amount of the swivel lever device 35. Therefore, when the discharge pressure P of the hydraulic pump 23 reaches a predetermined pressure (cutoff pressure Pc), the controller 45 reduces the discharge flow rate Q of the hydraulic pump 23 according to the characteristic line 103 in FIG. As a result, the flow rate of the hydraulic oil discharged from the relief valve 28 is reduced, and the energy loss can be reduced.

In the above-described embodiment, the case where the turning direction detector is the turning angular velocity sensor 41 has been described as an example. The present invention is not limited to this, and the turning direction detector may be, for example, various displacement sensors or speed sensors as long as the turning direction can be detected.

In the above-described embodiment, the hydraulic excavator 1 has been described as an example of a construction machine. The present invention is not limited to this, and can be applied to various construction machines provided with a swivel body, such as a hydraulic crane.

1 Hydraulic excavator (construction machinery)
2 Lower traveling body 2A, 4A Hydraulic motor 3 Upper swivel body (swivel body)
4 Swivel device 22 Engine 23 Hydraulic pump 24 Regulator 32 Control valve 35 Swivel lever device 41 Swivel angular velocity sensor (swivel direction detector)
45 Controller 48,49 Proportional electromagnetic pressure reducing valve

Claims (3)

A hydraulic motor that swivels and drives the swivel body,
A variable displacement hydraulic pump that is driven by a prime mover to supply pressure oil to the hydraulic motor and whose discharge flow rate is controlled within the range of horsepower characteristics of the prime mover by a regulator as horsepower control.
A control valve provided between the hydraulic motor and the hydraulic pump to control the flow rate and direction of the pressure oil supplied from the hydraulic pump to the hydraulic motor in response to a turning command.
A swivel lever device that outputs the swivel command according to the amount of operation,
A swivel direction detector that detects the swivel direction of the swivel body,
In a construction machine including the hydraulic pump and a controller for controlling the control valve.
The controller
When the discharge pressure of the hydraulic pump becomes equal to or higher than a predetermined pressure, the discharge flow rate of the hydraulic pump is reduced from the flow rate set by the horsepower control.
When the swivel command is output from the swivel lever device in the swivel stop state, or the swivel direction corresponding to the swivel command output from the swivel lever device and the swivel body detected by the swivel direction detector. If the turning direction is the same, it is determined to be an acceleration operation, and if the turning direction in response to the turning command is different from the turning direction of the turning body, it is determined to be a reverse lever operation.
When it is determined that the acceleration operation or the reverse lever operation is performed, when the operation amount of the turning lever device exceeds a predetermined value, the control valve is controlled to be switched to the fully open position, and the discharge flow rate of the hydraulic pump is performed. Based on, the turning speed of the turning body and the braking pressure of the hydraulic motor are controlled.
When it is determined that the operation is different from both the acceleration operation and the reverse lever operation, the control valve is controlled so that the valve opening degree corresponds to the operation amount of the turning lever device, and the control valve is operated. A construction machine characterized in that the swivel speed of the swivel body and the brake pressure of the hydraulic motor are controlled based on the valve opening degree of the valve and the discharge flow rate of the hydraulic pump. When the controller determines that the acceleration operation or the reverse lever operation is performed and the operation amount of the turning lever device is smaller than a predetermined value, the control valve is adjusted according to the operation amount of the turning lever device. It is characterized in that the valve opening is controlled so that the valve opening is controlled, and the turning speed of the swivel body and the brake pressure of the hydraulic motor are controlled based on the valve opening of the control valve and the discharge flow rate of the hydraulic pump. The construction machine according to claim 1. The construction machine according to claim 1, wherein the controller controls the hydraulic pump by using the regulator so that the discharge flow rate corresponds to the operation amount of the turning lever device.

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