JP7181128B2 - construction machinery - Google Patents

Description

The present invention relates to a construction machine equipped with a hydraulic drive system that directly drives a hydraulic actuator with a hydraulic pump.

In recent years, in construction machinery such as hydraulic excavators, in order to reduce the throttle element in the hydraulic circuit that drives the hydraulic actuators such as hydraulic cylinders and reduce the fuel consumption rate, hydraulic oil is supplied from the hydraulic drive source such as the hydraulic pump to the hydraulic actuators. Development of a hydraulic circuit (defined as a closed circuit) in which the hydraulic fluid that has been sent and worked by the hydraulic actuator is returned to the hydraulic pump instead of being returned to the tank is being developed.

Patent Literature 1 describes a configuration in which an actuator and a pump are connected in a closed circuit to a backhoe shovel.

JP 2016-145603 A

Consider the above prior art application to loading shovels instead of backhoe shovels, for example. A loading shovel is a shovel that pushes out a bucket by extending an arm cylinder. A loading shovel pushes a bucket horizontally when excavating. When using the system shown in the prior art document, it is necessary to fine-tune the lever input in the arm cylinder extension direction and the boom cylinder retraction direction in order to achieve the horizontal pushing movement of the bucket. As a result, the operator is required to make complicated inputs, which increases the operator's load during repeated excavation operations.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a construction machine capable of linearly pushing out a bucket simply by an operator manipulating an arm in the pushing direction.

In order to achieve the above objects, the present invention provides a boom, an arm rotatably attached to the boom, a bucket rotatably attached to the arm, and an extension operation to raise the boom. a boom cylinder that drives the boom downward by retracting; an arm cylinder that drives the arm in the pushing direction by extending the arm and drives the arm in the retracting direction by retracting; the boom and the arm; a double tilting first hydraulic pump connectable to the boom cylinder in a closed circuit, a second hydraulic pump connectable to the arm cylinder, and the operating device a controller for controlling a flow rate of pressure oil supplied from the first hydraulic pump to the boom cylinder and a flow rate of pressure oil supplied from the second hydraulic pump to the arm cylinder in accordance with an operation; a boom angle detection device for detecting the angle of the boom; and a bucket trajectory selection device for selecting either an arc trajectory or a straight trajectory as the movement trajectory of the bucket when the arm pushes out. , the controller detects the boom angle detection device at a time point when an instruction to push the arm is started via the operation device when the linear trajectory is selected via the bucket trajectory selection device. A constant flow rate ratio is calculated according to the boom initial angle, which is the angle of the boom, and the arm The discharge flow rate of the first hydraulic pump is controlled so that the flow rate obtained by multiplying the flow rate supplied to the bottom chamber of the cylinder by the flow rate ratio is discharged from the bottom chamber of the boom cylinder.

According to the present invention configured as described above, when a linear trajectory is selected via the bucket trajectory selection device and an arm pushing operation is instructed via the operation device, a constant boom angle is set based on the boom initial angle. The flow rate obtained by multiplying the flow rate supplied to the bottom chamber of the arm cylinder by the flow rate ratio while the arm pushing operation is instructed via the operating device and the boom operation is not instructed. is discharged from the bottom chamber of the boom cylinder. As a result, the bucket can be pushed out linearly only by the operator manipulating the arm in the pushing direction.

According to the construction machine of the present invention, the bucket can be pushed out linearly simply by the operator manipulating the arm in the push-out direction, so it is possible to reduce the load on the operator during excavation work.

1 is a side view of a hydraulic excavator according to a first embodiment of the present invention; FIG. FIG. 2 is a diagram showing the operation of the hydraulic excavator shown in FIG. 1 during excavation; 2 is a schematic configuration diagram of a hydraulic drive device mounted on the hydraulic excavator shown in FIG. 1; FIG. 4 is a functional block diagram of the controller shown in FIG. 3; FIG. Lever input, hydraulic pump discharge flow rate, switching valve open/closed state, and when the horizontal push mode is selected via the horizontal push arc excavation changeover switch and the arm push independent operation is instructed via the lever. FIG. 4 is a diagram showing changes in speed (cylinder speed) of an arm cylinder and a boom cylinder; 5 is a flow chart showing processing of a command calculation unit of the controller shown in FIG. 4; Lever input, hydraulic pump flow rate, switching valve open/closed state, and arm when arc excavation mode is selected via the horizontal push arc excavation changeover switch and arm push independent operation is instructed via the lever. Figure 2 shows changes in cylinder and boom cylinder speed (cylinder speed); FIG. 5 is a functional block diagram of a controller in a second embodiment of the invention; FIG. 9 is a flow chart showing processing of a command calculation unit of a controller according to the second embodiment of the present invention; FIG.

Hereinafter, a hydraulic excavator will be described as an example of a construction machine according to an embodiment of the present invention with reference to the drawings. In addition, in each figure, the same code|symbol is attached|subjected to the same member, and the overlapping description is abbreviate|omitted suitably.

FIG. 1 is a side view of a hydraulic excavator according to a first embodiment of the invention.

In FIG. 1, a hydraulic excavator 100 includes a lower traveling body 101 equipped with a crawler type travel device 8, an upper revolving body 102 mounted on the lower traveling body 101 via a revolving device 7 so as to be able to turn, and an upper revolving body. A front working device 103 is attached to the front part of the body 102 so as to be rotatable in the vertical direction. A cab 104 on which an operator rides is provided on the upper swing body 102 . A lever 51 (shown in FIG. 3), which will be described later, is arranged in the cab 104 .

The front working device 103 includes a boom 2 attached to the front portion of the upper revolving body 102 so as to be vertically rotatable; A bucket 6 connected to the tip of an arm 4 so as to be rotatable in the vertical or longitudinal direction, a boom cylinder 1 that drives the boom 2, an arm cylinder 3 that drives the arm 4, and a bucket cylinder 5 that drives the bucket 6. and

A hydraulic excavator 100 according to this embodiment is a loading excavator, and is configured such that the bucket 6 is pushed forward by extending the arm cylinder 3 or the bucket cylinder 5 . As shown in FIG. 2, the hydraulic excavator 100 during excavation moves from a posture (starting posture) in which the arm 4 is pulled and the boom 2 is raised to a posture in which the arm 4 is pushed out and the boom 2 is lowered (end posture). repeat.

FIG. 3 is a schematic configuration diagram of a hydraulic drive device mounted on the hydraulic excavator 100. As shown in FIG. For the sake of simplification of explanation, FIG. 3 shows only the parts related to the driving of the boom cylinder 1 and the arm cylinder 3, and omits the parts related to the driving of other actuators.

In FIG. 3, a hydraulic drive device 300 includes a boom cylinder 1, an arm cylinder 3, a lever 51 as an operating device for instructing the operating directions and required speeds of the boom cylinder 1 and the arm cylinder 3, and a power source. An engine 9, a power transmission device 10 that distributes the power of the engine 9, hydraulic pumps 12 to 15 and a charge pump 11 that are driven by the power distributed by the power transmission device 10, and hydraulic pumps 12 to 15. Switching valves 40 to 47, proportional valves 48, 49, switching valves 40 to 47, proportional valves 48, 49, and regulators 12a, 13a, 14a, 15a to be described later. and a controller 50 for controlling the

An engine 9 as a power source is connected to a power transmission device 10 that distributes power. Hydraulic pumps 12 to 15 and a charge pump 11 are connected to the power transmission device 10 .

The hydraulic pumps 12 and 13 are provided with a dual tilt swash plate mechanism having a pair of input/output ports, and regulators 12a and 13a for adjusting the tilt angles of the tilt swash plates. The hydraulic pumps 14, 15 have a single tilting swash plate function with an input port and an output port, and regulators 14a, 15a for adjusting the tilt angle of the tilting swash plate. The regulators 12a, 13a, 14a, 15a adjust the tilting angles of the tilting swash plates of the hydraulic pumps 12-15 according to signals from the controller 50. FIG.

The hydraulic pumps 12 and 13 can control the discharge flow rate and direction of the hydraulic oil from the input/output ports by adjusting the tilt angles of the tilt swash plates. The hydraulic pumps 12 and 13 also function as hydraulic motors when supplied with pressure oil.

Flow paths 200 and 201 are connected to a pair of input/output ports of the hydraulic pump 12 , and switching valves 40 and 41 are connected to the flow paths 200 and 201 . The switching valves 40 and 41 switch between communication and blocking of the flow path according to a signal from the controller 50 . The switching valves 40 and 41 are closed when there is no signal from the controller 50 .

The switching valve 40 is connected to the boom cylinder 1 via passages 210 and 211 . When the switching valve 40 is brought into communication by a signal from the controller 50, the hydraulic pump 12 is connected to the boom cylinder 1 via the flow paths 200, 201, the switching valve 40, and the flow paths 210, 211, thereby closing. configure the circuit.

The switching valve 41 is connected to the arm cylinder 3 via passages 213 and 214 . When the switching valve 41 is brought into communication by a signal from the controller 50, the hydraulic pump 12 is connected to the arm cylinder 3 via the flow paths 200, 201, the switching valve 41, and the flow paths 213, 214, thereby closing. configure the circuit.

Flow paths 202 and 203 are connected to a pair of input/output ports of the hydraulic pump 13 , and switching valves 42 and 43 are connected to the flow paths 202 and 203 . The switching valves 42 and 43 switch between communication and blocking of the flow path according to a signal from the controller 50 . The switching valves 42 and 43 are closed when there is no signal from the controller 50 .

The switching valve 42 is connected to the boom cylinder 1 via passages 210 and 211 . When the switching valve 42 is brought into communication by a signal from the controller 50, the hydraulic pump 13 is connected to the boom cylinder 1 through the flow paths 202, 203, the switching valve 42, and the flow paths 210, 211, thereby being closed. configure the circuit.

The switching valve 43 is connected to the arm cylinder 3 via passages 213 and 214 . When the switching valve 43 is brought into communication by a signal from the controller 50, the hydraulic pump 13 is connected to the arm cylinder 3 via the flow paths 202, 203, the switching valve 43, and the flow paths 213, 214, thereby closing. configure the circuit.

The output port of the hydraulic pump 14 is connected to the switching valves 44 and 45, the proportional valve 48 and the relief valve 21 via the flow path 204. An input port of the hydraulic pump 14 is connected to the tank 25 .

The relief valve 21 releases hydraulic oil to the tank 25 to protect the circuit when the flow path pressure exceeds a predetermined pressure.

The switching valves 44 and 45 switch communication and blockage of the flow path according to a signal from the controller 50 . When there is no signal from the controller 50, the switching valves 44, 45 are closed.

The switching valve 44 is connected to the bottom chamber 1 a of the boom cylinder 1 via a flow path 210 .

The switching valve 45 is connected to the bottom chamber 3 a of the arm cylinder 3 via a flow path 213 .

The proportional valve 48 changes its opening area according to a signal from the controller 50 to control the flow rate. In the absence of a signal from controller 50, proportional valve 48 is held at its maximum open area. Further, when the switching valves 44 and 45 are closed, the controller 50 gives a signal to the proportional valve 48 so that the opening area is preset according to the discharge flow rate of the hydraulic pump 14 .

The output port of the hydraulic pump 15 is connected to the switching valves 46 and 47, the proportional valve 49 and the relief valve 22 via the flow path 205. An input port of the hydraulic pump 15 is connected to the tank 25 .

The relief valve 22 releases hydraulic oil to a tank 25 to protect the circuit when the flow path pressure exceeds a predetermined pressure.

The switching valves 46 and 47 switch between communication and blocking of the flow path according to a signal from the controller 50 . When there is no signal from the controller 50, the switching valves 46, 47 are closed.

The switching valve 46 is connected to the bottom chamber 1 a of the boom cylinder 1 via a flow path 210 .

The switching valve 47 is connected to the bottom chamber 3 a of the arm cylinder 3 via a flow path 213 .

The proportional valve 49 changes its opening area according to a signal from the controller 50 to control the flow rate. In the absence of a signal from controller 50, proportional valve 49 is held at its maximum open area. When the switching valves 46 and 47 are closed, the controller 50 gives a signal to the proportional valve 49 so that the opening area is preset according to the discharge flow rate of the hydraulic pump 15 .

A discharge port of the charge pump 11 is connected via a charge line 212 to the charge relief valve 20 and the charge check valves 26, 27, 28a, 28b, 29a and 29b. A suction port of the charge pump 11 is connected to the tank 25 . The charge pump 11 supplies pressure oil to the charge line 212 .

The charge relief valve 20 releases the hydraulic oil to the tank 25 when the flow path pressure of the charge line 212 exceeds a predetermined pressure, and keeps the pressure of the charge line 212 constant.

The charge check valve 26 supplies pressure oil from the charge line 212 to the flow paths 200 and 201 when the pressure in the flow paths 200 and 201 falls below the pressure set by the charge relief valve 20 .

The charge check valve 27 supplies pressure oil from the charge line 212 to the flow paths 202 and 203 when the pressure in the flow paths 202 and 203 falls below the pressure set by the charge relief valve 20 .

The charge check valves 28 a and 28 b supply pressure oil from the charge line 212 to the flow paths 210 and 211 when the pressure in the flow paths 210 and 211 falls below the pressure set by the charge relief valve 20 .
The charge check valves 29 a and 29 b supply pressure oil from the charge line 212 to the flow paths 213 and 214 when the pressure in the flow paths 213 and 214 falls below the pressure set by the charge relief valve 20 .

Relief valves 30a and 30b provided in flow paths 200 and 201 release hydraulic fluid to charge line 212 to protect the circuit when the flow path pressure exceeds a predetermined pressure.

Relief valves 31a and 31b provided in flow paths 202 and 203 release hydraulic oil to charge line 212 to protect the circuit when the flow path pressure exceeds a predetermined pressure.

The boom cylinder 1 is a hydraulic single-rod cylinder that expands and contracts when supplied with hydraulic oil. A flow path 210 is connected to the bottom chamber 1 a of the boom cylinder 1 , and a flow path 211 is connected to the rod chamber 1 b of the boom cylinder 1 . The expansion and contraction direction of the boom cylinder 1 depends on the supply direction of hydraulic oil.

Relief valves 32a and 32b provided in flow paths 210 and 211 release hydraulic fluid to charge line 212 to protect the circuit when the flow path pressure exceeds a predetermined pressure.

Flushing valves 34 provided in flow paths 210 and 211 discharge surplus oil in the flow paths to charge line 212 .

The arm cylinder 3 is a hydraulic single-rod cylinder that expands and contracts when supplied with hydraulic oil. A flow path 213 is connected to the bottom chamber 3 a of the arm cylinder 3 , and a flow path 214 is connected to the rod chamber 3 b of the arm cylinder 3 . The expansion and contraction direction of the arm cylinder 3 depends on the supply direction of hydraulic oil.

Relief valves 33a and 33b provided in flow paths 213 and 214 release hydraulic fluid to charge line 212 to protect the circuit when the flow path pressure exceeds a predetermined pressure.

Flushing valves 35 provided in flow paths 210 and 211 discharge surplus oil in the flow paths to charge line 212 .

A stroke sensor 60 installed in the boom cylinder 1 measures the stroke of the boom cylinder 1 and inputs it to the controller 50 . The controller 50 calculates the attitude (angle) of the boom 2 from the stroke of the boom cylinder 1 .

A stroke sensor 61 installed in the arm cylinder 3 measures the stroke of the arm cylinder 3 and inputs it to the controller 50 . The controller 50 calculates the attitude (angle) of the arm 4 from the stroke of the arm cylinder 3 .

In this embodiment, the stroke sensors 60 and 61 are used as means for detecting the attitudes of the boom 2 and arm 4, but angle sensors attached to the rotation shafts of the boom 2 and arm 4, and IMU attached to the boom 2 and arm may be used.

The lever 51 is operated by an operator and inputs the operation amount for each actuator to the controller 50 .

The horizontal extrusion arc excavation changeover switch 52 is operated by an operator to input to the controller 50 the result of selection between a horizontal extrusion mode and an arc excavation mode, which will be described later.

FIG. 4 is a functional block diagram of the controller 50. As shown in FIG. As in FIG. 3, FIG. 4 shows only the parts related to the driving of the boom cylinder 1 and the arm cylinder 3, and omits the parts related to the driving of other actuators.

4, the controller 50 has a lever operation amount calculator F11, a boom attitude calculator F12b, an arm attitude calculator F12a, and a command calculator F13.

The lever operation amount calculation unit F11 calculates the operating directions and target operating speeds of the actuators 1 and 3 according to the input from the lever 51, and inputs them to the command calculation unit F13.

The boom attitude calculator F12b calculates the attitude (angle) of the boom 2 from the value of the stroke sensor 60 (the stroke of the boom cylinder 1) and inputs it to the command calculator F13.

The arm attitude calculator F12b calculates the attitude (angle) of the arm 4 from the value of the stroke sensor 61 (the stroke of the arm cylinder 3) and inputs it to the command calculator F13.

The command calculation unit F13 controls the switching valves 40 to 47, the proportional valves 48 and 49, and the regulators 12a to 15a based on inputs from the lever operation amount calculation unit F11, the boom attitude calculation unit F12b, and the arm attitude calculation unit F12a. Calculates the command value of and outputs it.

The command calculation unit F13 has a horizontal extrusion arc excavation selection unit F14, a boom flow ratio calculation unit F15, and an actuator allocation flow calculation unit F16.

The horizontal push arc excavation selection unit F14 selects either the horizontal push mode or the arc excavation mode based on the input from the horizontal push arc excavation switch 52, and inputs it to the boom flow rate ratio calculation unit F15.

When the horizontal extrusion mode is input from the horizontal extrusion arc excavation selection unit F14, the boom flow ratio calculation unit F15 adjusts the bottom chamber of the arm cylinder 3 based on the inputs from the boom posture calculation unit F12b and the arm posture calculation unit F12a. A flow rate ratio α, which is the ratio of the discharge flow rate Qb from the bottom chamber 1a of the boom cylinder 1 to the supply flow rate Qa to the boom cylinder 3a, is calculated. A supply flow rate Qb to the boom cylinder 1 is represented by the following equation (1) using a flow rate ratio α.

Here, the flow rate ratio α is geometrically determined based on the initial angle θb0 of the boom 2 and the initial angle θa0 of the arm 4 . That is, the flow ratio α is represented by the following equation (2).

Note that when the arm cylinder 3 is always at the maximum contraction length at the start of excavation, the flow rate ratio α is determined based only on the initial angle θb0 of the boom 2 . That is, the supply flow rate ratio α is represented by the following equation (3).

Actuator allocation flow rate calculation section F16 calculates command values for switching valves 40-47, proportional valves 48 and 49, and regulators 12a-15a based on inputs from lever operation amount calculation section F11 and boom flow rate ratio calculation section F15. Calculate and output.

Next, the operation of the hydraulic drive device 300 according to this embodiment will be described.

(1) When not operated In FIG. 3, when the lever 51 is not operated, the hydraulic pumps 12 to 15 are controlled to the minimum tilt angle, the switching valves 40 to 47 are all closed, and the boom cylinder 1 and the arm cylinder 3 are closed. is held in a stopped state.

(2) During arm push operation (when horizontal push is selected)
FIG. 5 shows the input of the lever 51, the hydraulic pumps 13, 15, and the hydraulic pumps 13, 15, and 51 when the horizontal extrusion mode is selected via the horizontal extrusion arc excavation changeover switch 52 and the single arm pushing operation is instructed via the lever 51. 12, changes in the open/closed states of switching valves 43, 47, and 40, and changes in the speeds of arm cylinder 3 and boom cylinder 1 (cylinder speed).

From time t0 to time t1, the input of lever 51 is 0, and arm cylinder 3 and boom cylinder 1 are stationary.

From time t1 to time t2, the input to the lever 51 increases the command value for extending the arm cylinder 3 to the maximum value.

FIG. 6 is a flow chart showing the processing of the command calculation section F13 of the controller 50. As shown in FIG.

First, in step S1, the controller 50 determines whether or not the input of the lever 51 is from the arm alone. Since this operation is a single arm pushing operation, the process proceeds to step S2.

At step S2, the controller 50 determines whether or not the horizontal extrusion mode is selected. Since the horizontal extrusion mode is selected in this operation, the process proceeds to step S3.

In step S3, the controller 50 calculates the posture (angle) of the boom 2 based on the signal from the stroke sensor 60 (the stroke of the boom cylinder 1). Further, the ratio (flow ratio α) of the discharge flow from the bottom chamber 1a of the boom cylinder 1 to the supply flow to the bottom chamber 3a of the arm cylinder 3 for horizontal pushing operation is calculated, and the process proceeds to step S4.

In step S4, the controller 50 calculates the supply flow rate Qa to the bottom chamber 3a of the arm cylinder 3 based on the lever input of the single arm pushing operation. Further, the discharge flow rate Qb from the bottom chamber 1a of the boom cylinder 1 is calculated from the flow rate ratio α obtained in step S3 and the supply flow rate Qa to the bottom chamber 3a of the arm cylinder 3, and the process is completed.

As shown in FIG. 5, from time t1 to time t2, the regulator is operated so that the supply flow rate Qa to the bottom chamber 3a of the arm cylinder 3 calculated in step S4 shown in FIG. 13a and 15a are controlled. In order to connect the hydraulic pump 13 to the arm cylinder 3, the switching valve 43 is opened at time t1, and in order to connect the hydraulic pump 15 to the bottom chamber 3a of the arm cylinder 3, the switching valve 47 is opened at time t1.

Further, the discharge flow rate of the hydraulic pump 12 is controlled so that the discharge flow rate Qb from the bottom chamber 1a of the boom cylinder 1 calculated in step S4 shown in FIG. In order to connect the hydraulic pump 12 to the boom cylinder 1, the switching valve 40 is opened at time t1.

As described above, the contraction speed of the boom cylinder 1 is appropriately controlled with respect to the extension speed of the arm cylinder 3 by controlling the pump discharge flow rate and opening/closing of the switching valve in response to the lever input of the arm single push operation. to achieve horizontal extrusion.

In this embodiment, only the hydraulic pump 12 is used for retracting the boom cylinder 1 . The hydraulic pump 12 is a closed circuit pump, and when the boom is lowered, the pressure in the bottom chamber 1a is higher than the pressure in the rod chamber 1b. gives regenerative torque to The regenerated torque can be used to drive the hydraulic pumps 13, 15, and the fuel consumption of the engine 9 can be reduced. In addition, by controlling the boom lowering only with a pump, it is possible to improve the control accuracy of the flow rate compared to control using a valve that fluctuates the flow rate due to the influence of pressure, so the horizontal extrusion can follow the target trajectory. can be improved.

When only the hydraulic pump 12 is used for retracting the boom cylinder 1 as in this embodiment, the surplus flow rate generated by the pressure receiving area ratio between the bottom side and the rod side of the cylinder flows through the flushing valve 34 into the charge line 212 . is discharged to As the discharge flow increases, the pressure in charge line 212 increases. In order to prevent this, the switching valve 44 may be opened at time t<b>1 to discharge a portion of the flow from the proportional valve 48 to the tank 25 .

(3) During arm push operation (when circular excavation is selected)
FIG. 7 shows the input of the lever 51, the hydraulic pumps 13, 15, and when the arc excavation mode is selected via the horizontal push arc excavation change-over switch 52 and the single arm push operation is instructed via the lever 51. 12, the open/closed states of switching valves 43, 47, and 40, and changes in the speed of arm cylinder 3 and boom cylinder 1 (cylinder speed).

From time t0 to time t1, the input of lever 51 is 0, and arm cylinder 3 and boom cylinder 1 are stationary.

From time t1 to time t2, the input to the lever 51 increases the command value for extending the arm cylinder 3 to the maximum value.

First, in step S1 shown in FIG. 6, the controller 50 determines whether or not the input of the lever 51 is from the arm alone. Since this operation is a single arm pushing operation, the process proceeds to step S2.

At step S2, the controller 50 determines whether or not the horizontal extrusion mode is selected. Since the arc excavation mode is selected in this operation, the process proceeds to step S5.

In step S5, the controller 50 calculates the supply flow rate Qa to the bottom chamber 3a of the arm cylinder 3 based on the lever input of the single arm pushing operation, and completes the process.

As shown in FIG. 5, from time t1 to time t2, the regulator is operated so that the supply flow rate Qa to the bottom chamber 3a of the arm cylinder 3 calculated in step S4 shown in FIG. 13a and 15a are controlled. In order to connect the hydraulic pump 13 to the arm cylinder 3, the switching valve 43 is opened at time t1, and in order to connect the hydraulic pump 15 to the bottom chamber 3a of the arm cylinder 3, the switching valve 47 is opened at time t1.

On the other hand, since the boom cylinder 1 is not driven, the discharge flow rate of the hydraulic pump 12 is maintained at 0, and the switching valve 40 is also maintained closed.

As described above, the bucket 6 connects the boom 2 and the arm 4 in order to drive only the arm cylinder 3 by controlling the discharge flow rate of the pump and the opening and closing of the switching valve in response to the lever input of the independent arm push operation. Moved in an arc trajectory around a point.

In this embodiment, a boom 2, an arm 4 rotatably attached to the boom 2, and a bucket 6 rotatably attached to the arm 4 are extended to drive the boom 2 in the upward direction and contract. A boom cylinder 1 that drives the boom 2 downward by operation, an arm cylinder 3 that drives the arm 4 in the extension direction by extension operation and drives the arm 4 in the retraction direction by contraction operation, and operations of the boom 2 and the arm 4. an operation device 51 for instructing, a bi-tilting first hydraulic pump 12 connectable to the boom cylinder 1 in a closed circuit, second hydraulic pumps 13 and 15 connectable to the arm cylinder 3, and an operation The flow rate of pressure oil supplied from the first hydraulic pump 12 to the boom cylinder 1 and the flow rate of pressure oil supplied from the second hydraulic pumps 13, 15 to the arm cylinder 3 are controlled according to the operation of the device 51. A construction machine 100 comprising a controller 50 that detects the angle of a boom 2, and either an arc locus or a linear locus is selected as the moving locus of the bucket 6 during the pushing operation of the arm 4. The controller 50 is provided with a bucket trajectory selection device 52, and when the linear trajectory is selected via the bucket trajectory selection device 52, the controller 50 starts to instruct the push operation of the arm 4 via the operation device 51. A constant flow ratio α corresponding to the initial boom angle θb0, which is the angle of the boom 2 detected by the boom angle detection device 60, is calculated. is not instructed, the flow rate Qb obtained by multiplying the flow rate Qa supplied to the bottom chamber 3a of the arm cylinder 3 by the flow rate ratio α is discharged from the bottom chamber 1a of the boom cylinder 1. The discharge flow rate of the pressure pump 12 is controlled.

According to the present invention configured as described above, when the straight trajectory is selected via the bucket trajectory selection device 52 and the pushing operation of the arm 4 is instructed via the operation device 51, the boom initial angle θb0 A constant flow rate ratio α is calculated based on the flow rate supplied to the bottom chamber of the arm cylinder while the pushing operation of the arm 4 is instructed via the operation device 51 and the operation of the boom 2 is not instructed. The discharge flow rate of the first hydraulic pump is controlled so that the flow rate obtained by multiplying the flow rate ratio is discharged from the bottom chamber of the boom cylinder. As a result, the bucket can be pushed out linearly only by the operator instructing the push-out motion of the arm via the operating device.

Further, the construction machine 100 according to the present embodiment further includes an arm angle detection device 61 that detects the angle of the arm 4, and the controller 50 detects the angle of the arm 4 when an instruction to push the arm 4 through the operation device 51 is started. based on the arm initial angle θa0, which is the angle of the arm 4 detected by the arm angle detection device 61, and the boom initial angle θb0. Thereby, it is possible to adjust the height of the bucket 6 when moving the bucket 6 along the linear locus.

Also, a plurality of hydraulic actuators 1 and 3 including the boom cylinder 1 and the arm cylinder 3, a plurality of hydraulic pumps 12 to 15 including a first hydraulic pump 12 and a second hydraulic pump 13 and 15, It comprises a plurality of switching valves 40-47 capable of switching connection states between the plurality of hydraulic actuators 1, 3 and the plurality of hydraulic pumps 12-15. As a result, in the construction machine 100 equipped with the hydraulic closed circuit system, the bucket 6 can be pushed out linearly only by the operator manipulating the arm 4 in the pushing direction.

A hydraulic excavator 100 according to a second embodiment of the present invention will be described with a focus on differences from the first embodiment. In the first embodiment, the pushing direction of the bucket 6 was limited to the horizontal direction, but this embodiment is constructed so that the angle of the pushing direction can be changed.

FIG. 8 is a functional block diagram of the controller 50 in this embodiment. In FIG. 8, the difference from the first embodiment (shown in FIG. 4) is that the cab 104 is provided with a push angle indicator 62 for instructing the required push angle of the bucket 6, the horizontal push arc excavation changeover switch 52 and the horizontal The difference is that a linear push arc excavation selection switch 52A and a linear push arc excavation selection part F14A are provided instead of the push arc excavation selection part F14. A signal from the extrusion angle indicator 62 is input to the supply flow rate ratio calculator F15 of the controller 50 .

The boom flow ratio calculation unit F15 in this embodiment receives inputs from the boom attitude calculation unit F12b, the arm attitude calculation unit F12a, and the push angle instruction device 62 when the straight push mode is input from the straight push arc excavation selection unit F14A. Calculate the flow ratio α based on. Here, the supply flow rate ratio α is determined from the initial posture θb0 of the boom 2, the initial posture θa0 of the arm 4, and the required thrust angle θd. That is, the supply flow rate ratio α is represented by the following equation (4).

FIG. 9 is a flow chart showing the processing of the command calculation section F13 of the controller 50 in this embodiment. 9 differs from the first embodiment (shown in FIG. 6) in that steps S2A and S3A are provided instead of steps S2 and S3.

At step S2A, the controller 50 determines whether or not the linear extrusion mode is selected.

In step S3A, the controller 50 calculates the posture (angle) of the boom 2 based on the signal from the stroke sensor 60 (the stroke of the boom cylinder 1). Further, the ratio of the discharge flow rate from the bottom chamber 1a of the boom cylinder 1 to the supply flow rate to the bottom chamber 3a of the arm cylinder 3 for performing the linear push operation (flow rate ratio α) is calculated, and the process proceeds to step S4.

The construction machine 100 according to the present embodiment further includes a thrust angle indicator 62 that instructs the ground angle, which is the angle formed by the linear trajectory of the bucket 6 with respect to the ground. A flow ratio α is determined based on θa0 and the ground angle.

According to the construction machine 100 according to the present embodiment configured as described above, the operator can push the bucket 6 linearly at a desired angle simply by operating the arm 4 in the pushing direction.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. It is also possible to add part of the configuration of another embodiment to the configuration of one embodiment, or to delete part of the configuration of one embodiment or replace it with part of another embodiment. It is possible.

Reference Signs List 1 Boom cylinder 1a Bottom chamber 1b Rod chamber 2 Boom 3 Arm cylinder 3a Bottom chamber 3b Rod chamber 4 Arm 5 Bucket cylinder 6 Bucket 7 Rotating Apparatus 8 Traveling device 9 Engine 10 Power transmission device 11 Charge pump 12 Hydraulic pump (first hydraulic pump) 12a Regulator 13 Hydraulic pump (second hydraulic pump ), 13a... regulator, 14... hydraulic pump, 14a... regulator, 15... hydraulic pump (second hydraulic pump), 15a... regulator, 20... charge relief valve, 21, 22... relief valve, 25... tank , 26, 27... Charge check valve 28a, 28b... Charge check valve 29a, 29b... Charge check valve 30a, 30b... Relief valve 31a, 31b... Relief valve 32a, 32b... Relief valve 33a , 33b... Relief valve, 34, 35... Flushing valve, 40 to 47... Switching valve, 48, 49... Proportional valve, 50... Controller, 51... Lever (operating device), 52... Horizontal extrusion circular excavation switch (bucket trajectory Selection device), 52A... Straight push arc excavation changeover switch (bucket trajectory selection device), 60... Stroke sensor (boom angle detection device), 61... Stroke sensor (arm angle detection device), 62... Push angle indication device, 100... Hydraulic excavator (construction machine) 101 Lower running body 102 Upper revolving body 103 Front working device 104 Cab 200 to 211, 213 Flow path 212 Charge line 300 Hydraulic drive device.

Claims (4)

boom and
an arm rotatably attached to the boom;
a bucket rotatably attached to the arm;
a boom cylinder that drives the boom in an upward direction by an extension operation and drives the boom in a downward direction by a contraction operation;
an arm cylinder that drives the arm in the pushing direction by extending the arm and drives the arm in the retracting direction by contracting the arm;
an operation device for instructing the operation of the boom and the arm;
a bi-tilting first hydraulic pump connectable to the boom cylinder in a closed circuit;
a second hydraulic pump connectable to the arm cylinder;
A flow rate of pressure oil supplied from the first hydraulic pump to the boom cylinder and a flow rate of pressure oil supplied from the second hydraulic pump to the arm cylinder are controlled according to the operation of the operating device. A construction machine comprising a controller,
a boom angle detection device that detects the angle of the boom;
a bucket trajectory selection device that selects either a circular arc trajectory or a straight trajectory as a movement trajectory of the bucket during the pushing operation of the arm,
When the linear trajectory is selected via the bucket trajectory selection device, the controller detects the boom angle detection device at the time when an instruction to push the arm is started via the operation device. A constant flow rate ratio corresponding to the boom initial angle, which is the angle of the boom, is calculated, and the arm cylinder is operated while the push operation of the arm is instructed via the operating device and the operation of the boom is not instructed. The discharge flow rate of the first hydraulic pump is controlled so that the flow rate obtained by multiplying the flow rate supplied to the bottom chamber of the boom cylinder by the flow rate ratio is discharged from the bottom chamber of the boom cylinder. . In the construction machine according to claim 1,
Further comprising an arm angle detection device for detecting the angle of the arm,
The controller operates based on the initial arm angle and the initial boom angle, which are angles of the arm detected by the arm angle detection device when an instruction to push the arm is started via the operating device. A construction machine characterized by calculating the flow rate ratio. In the construction machine according to claim 1,
a plurality of hydraulic actuators including the boom cylinder and the arm cylinder;
a plurality of hydraulic pumps including the first hydraulic pump and the second hydraulic pump;
A construction machine comprising: a plurality of switching valves capable of switching connection states between the plurality of hydraulic actuators and the plurality of hydraulic pumps. In the construction machine according to claim 2,
Further comprising an extrusion angle indication device that indicates a ground angle that is the angle that the straight line trajectory makes with the ground,
The construction machine, wherein the controller determines the flow rate ratio based on the boom initial angle, the arm initial angle, and the ground angle.

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