JP2020143544A - Construction machine - Google Patents

Abstract

To provide a construction machine that can prevent a delay in revolving operation of a revolving superstructure while preventing pressure losses from occurring when performing combined operation in which revolving operation and attachment operation are performed at the same time.SOLUTION: A capacity control unit 71 of a construction machine 100 is configured to perform control for adjusting the capacity of a revolving motor to a first capacity that is predetermined when performing revolving single operation in which revolving operation is performed but attachment operation is not performed. The capacity control unit 71 is configured to perform control for adjusting the capacity of the revolving motor to a second capacity that is larger than the first capacity when performing combined operation in which the revolving operation and the attachment operation are performed at the same time.SELECTED DRAWING: Figure 8

Description

The present invention relates to a construction machine including a substrate, an upper swing body mounted on the base body so as to be rotatable, and an attachment mounted on the upper swing body.

Generally, a construction machine is derived from a base, an upper swivel body mounted on the base so as to be swivel, an attachment mounted on the upper swivel body, a hydraulic pump for discharging hydraulic oil, and the hydraulic pump. A swivel motor that operates to swivel the upper swivel body by receiving the supply of the hydraulic oil to be discharged, and operates to operate the attachment by receiving the supply of the hydraulic oil discharged from the hydraulic pump. It is equipped with an actuator.

For example, Patent Document 1 uses oil from a plurality of actuators including a swivel motor and an arm cylinder, a plurality of hydraulic pumps, a plurality of control valves including both swivel motor and arm cylinder control valves, and oil from a plurality of hydraulic pumps. Hydraulic control with a switching valve that switches between the first position that supplies oil separately to both the swivel motor and arm cylinder control valves and the second position that merges and supplies oil from multiple hydraulic pumps. The circuit is disclosed. The hydraulic control circuit further includes a flow control valve as a meter-in throttle means for throttles the amount of oil supplied to the arm cylinder when a swivel and arm pull operation is performed. When pressure oil is supplied from a pump common to both the swivel motor and arm cylinder control valves, the swivel operation and drive to operate the swivel motor, which requires a relatively large operating pressure to drive, are required. The above-mentioned Patent Document 1 solves the problem that the turning operation is delayed with respect to the operation of the attachment when the combined operation in which the arm operation for operating the arm cylinder having a relatively small required operating pressure is performed at the same time is performed. The hydraulic control circuit described above suppresses the arm pulling speed by reducing the amount of oil supplied to the arm cylinder during the combined operation, and eliminates the delay in the turning operation during the combined operation in which the turning operation and the arm pulling operation are performed at the same time. Is what you do.

Japanese Unexamined Patent Publication No. 2001-295804

However, in the hydraulic control circuit described in Patent Document 1, since the meter-in throttle means reduces the amount of oil supplied to the arm cylinder during the combined operation, unnecessary pressure loss occurs. That is, a part of the work performed by the hydraulic pump is released as heat energy due to the pressure loss.

An object of the present invention is a construction capable of suppressing a delay in the turning operation of the upper turning body while suppressing a pressure loss in a combined operation in which a turning operation and an attachment operation are performed at the same time. To provide the machine.

As means for solving the above problems, the present inventors have described the capacity of the swivel motor and the differential pressure of the motor in the swivel motor (the differential pressure between the hydraulic oil supply oil passage and the hydraulic oil return oil passage connected to the swivel motor). ) And the relationship of turning torque. The turning torque is proportional to the product of the capacity of the turning motor and the differential pressure of the motor. Therefore, increasing the capacity of the swing motor during the combined operation makes it possible to increase the swing torque of the swing motor without reducing the amount of oil supplied to the arm cylinder by the meter-in throttle means as in the conventional case. To do. On the other hand, of the turning operation and the attachment operation, the motor differential pressure at the time of the turning single operation in which only the turning operation is performed without performing the attachment operation is larger than the motor differential pressure at the time of the combined operation. Increasing the capacity of the slewing motor during this slewing independent operation may cause an overtorque in which the slewing torque becomes too large during the slewing independent operation. Based on these points of view, the present inventors have adopted a variable displacement swivel motor as the swivel motor, and while adjusting the capacity of the swivel motor during the swivel independent operation to the first capacity, the above-mentioned We have come up with a capacity control that adjusts the capacity of the swing motor during a combined operation to a second capacity that is larger than the first capacity. This capacitance control makes it possible to secure the turning torque, particularly the starting torque, at the time of the combined operation even when the operating pressure of the actuator for attachment is low, and moreover, as in the conventional case, the said Since the meter-in throttle means is not required, it is possible to suppress the occurrence of pressure loss. Further, since the first capacity of the swivel motor at the time of the swivel single operation is smaller than the second capacity of the swivel motor at the time of the combined operation, the capacity control is the excess during the swivel single operation. It makes it possible to suppress the generation of torque.

The present invention has been made from such a viewpoint. Provided by the present invention are a construction machine, a base, an upper swivel mounted on the base so as to be swivel, an attachment mounted on the upper swivel, and hydraulic oil. A hydraulic pump that discharges the oil, a variable displacement swivel motor that operates to rotate the upper swing body by receiving the supply of the hydraulic oil discharged from the hydraulic pump, and the operation that is discharged from the hydraulic pump. To operate at least a part of the attachment, an actuator that receives oil supply and operates to operate at least a part of the attachment, a swivel operation member that receives a swivel operation for swiveling the upper swivel body, and an attachment. It is provided with an attachment operating member for receiving the attachment operation of the above and a capacity control unit. The capacity control unit controls to adjust the capacity of the swivel motor to a preset first capacity at the time of a swivel independent operation in which the swivel operation is performed but the attachment operation is not performed. It is configured to control to adjust the capacity of the swing motor to a second capacity larger than the first capacity at the time of a combined operation in which the turning operation and the attachment operation are performed at the same time. There is.

In this construction machine, the capacity of the swivel motor at the time of the combined operation is adjusted to the second capacity which is larger than the capacity of the swivel motor at the time of the swivel single operation. This means that the turning torque for turning the upper turning body, particularly the upper part, without or limiting the control of reducing the amount of oil to the cylinder accompanied by the occurrence of the pressure loss as in the conventional case. It is possible to secure the starting torque for starting the turning of the turning body. On the other hand, when the swivel single operation is performed, the capacity of the swivel motor is adjusted to the first capacity, so that the occurrence of the overtorque is suppressed.

The construction machine further includes a swivel speed detection unit for detecting the swivel speed of the upper swivel body, and the capacitance control unit has a speed threshold value at which the swivel speed detected by the swivel speed detection unit is preset. If it is less than, the swivel speed detected by the swivel speed detection unit is the speed threshold value while controlling for adjusting the capacity of the swivel motor at the time of the combined operation to the second capacity. In the above case, it is preferable that the control is performed so as to adjust the capacity of the swing motor at the time of the combined operation to a capacity smaller than the second capacity.

In this embodiment, when the turning speed is less than the speed threshold value, that is, when it is highly necessary to increase the starting torque during the combined operation, the capacity of the turning motor is increased to secure the starting torque. Allows you to. On the other hand, in this aspect, when the turning speed is equal to or higher than the speed threshold value during the combined operation, that is, when there is little need to increase the turning torque even during the combined operation, the turning motor The control for adjusting the capacity to the second capacity is not performed, and the capacity for adjusting the capacity of the swing motor to a capacity smaller than the second capacity is performed. This makes it possible to reduce the degree of decrease in the maximum speed of turning due to the increase in the capacity of the turning motor. In this embodiment, the capacity smaller than the second capacity may be the first capacity or a capacity different from the first capacity. Further, in this aspect, the speed threshold value is set to a value capable of determining whether or not the turning state of the upper turning body is the initial stage of turning. The initial stage includes a turning start time when the upper turning body starts turning from a stopped state, and a turning speed after the upper turning body starts turning.

The construction machine further includes a discharge pressure detection unit for detecting the discharge pressure of the hydraulic pump, and the capacity control unit has a discharge pressure threshold value at which the discharge pressure detected by the discharge pressure detection unit is preset. If it is less than, control is performed to adjust the capacity of the swivel motor to the second capacity at the time of the combined operation, while the discharge pressure detected by the discharge pressure detection unit is the discharge pressure. When it is equal to or more than the threshold value, it is preferable that the control is performed so as to adjust the capacity of the swing motor at the time of the combined operation to a capacity smaller than the second capacity.

In this embodiment, when the discharge pressure is less than the discharge pressure threshold value, that is, when it is highly necessary to increase the turning torque (particularly, the starting torque) during the combined operation, the capacity of the turning motor is increased. This makes it possible to secure the turning torque. On the other hand, in this aspect, when the discharge pressure is equal to or higher than the discharge pressure threshold value during the combined operation, that is, when the turning torque is secured even during the combined operation, the swing motor The control for adjusting the capacity to the second capacity is not performed, and the capacity for adjusting the capacity of the swing motor to a capacity smaller than the second capacity is performed. This makes it possible to reduce the degree of decrease in the maximum speed of turning due to the increase in the capacity of the turning motor. In this embodiment, the capacity smaller than the second capacity may be the first capacity or a capacity different from the first capacity. Further, in this aspect, whether or not the discharge pressure threshold value is a discharge pressure that enables smooth turning operation even when the capacity of the turning motor is smaller than the second capacity. Is set to a value that can be judged.

In the construction machine, the attachment includes a boom undulatingly supported by the upper swing body, an arm rotatably connected to the tip of the boom, and a tip attachment connected to the tip of the arm. The actuator is an actuator that operates to operate the arm, and the attachment operation may be an operation for operating the arm.

In this aspect, in the combined operation of the turning operation and the arm operation for operating the arm, the occurrence of the pressure loss as in the conventional case is suppressed even when the operating pressure of the arm is low. It is possible to secure the turning torque (particularly the starting torque) while enabling the above.

In the construction machine, the attachment includes a boom undulatingly supported by the upper swing body, an arm rotatably connected to the tip of the boom, and at least one connected to the tip of the arm. The actuator includes a tip attachment, and the actuator is an actuator that operates to operate the tip attachment, and the attachment operation may be an operation for operating the tip attachment.

In this embodiment, even when the operating pressure of the tip attachment is low during the combined operation of the turning operation and the tip attachment operation for operating the tip attachment, the pressure loss as in the conventional case occurs. It is possible to secure the turning torque (particularly the starting torque) while making it possible to suppress the turning torque.

The construction machine further includes an inclination detection unit for detecting the inclination of the construction machine, and the capacity control unit has the inclination of the construction machine detected by the inclination detection unit less than a preset inclination threshold value. In some cases, while controlling for adjusting the capacity of the swivel motor to the second capacity during the combined operation, the tilt of the construction machine detected by the tilt detection unit is equal to or greater than the tilt threshold. If this is the case, control may be performed to adjust the capacity of the swivel motor at the time of the combined operation to a capacity smaller than the second capacity.

If the inclination of the construction machine is equal to or greater than the inclination threshold value, cavitation may occur on the suction side of the turning motor. Therefore, in this aspect, when there is a possibility that the cavitation may occur, that is, when the construction machine is arranged on an inclined ground having a predetermined inclination or more, the swivel motor uniformly operates even during the combined operation. The control for adjusting the capacity to the second capacity is not performed, and the capacity for adjusting the capacity of the swing motor to a capacity smaller than the second capacity is performed. This makes it possible to suppress the occurrence of the cavitation caused by the inclination of the construction machine. In this embodiment, the capacity smaller than the second capacity may be the first capacity or a capacity different from the first capacity.

The construction machine further includes an inclination detection unit for detecting the inclination of the construction machine and a rotation operation direction detection unit for detecting the operation direction of the rotation operation received by the rotation operation member, and the capacity thereof. The control unit is detected when the inclination of the construction machine detected by the inclination detection unit is less than the inclination threshold value, or the inclination of the construction machine detected by the inclination detection unit and the rotation operation direction detection unit. When the turning direction of the upper swivel body obtained based on the operating direction of the swivel operation is not the swirling / falling direction which is the direction including the component in the direction of gravity, the capacity of the swivel motor at the time of the combined operation is used. While performing control for adjusting to the second capacitance, the inclination of the construction machine detected by the inclination detection unit is equal to or higher than a preset inclination threshold, and the inclination is detected by the inclination detection unit. When the turning direction of the upper swivel body obtained based on the inclination of the construction machine and the operating direction of the swivel operation detected by the swivel operation direction detection unit is the swivel fall direction, the said in the combined operation. It is preferable that the control is performed so as to adjust the capacity of the swing motor to a capacity smaller than the second capacity.

In this aspect, when the inclination of the construction machine is less than the inclination threshold value or when the upper swing body is not swiveled in the swivel fall direction, cavitation is unlikely to occur in the swivel motor. During the combined operation, control is performed to adjust the capacity of the swivel motor to the second capacity. In particular, when the upper swivel body swivels in a direction opposite to the swivel-falling direction, that is, in a direction against gravity during the combined operation, the swivel torque (particularly, the starting torque) is applied during the combined operation. There is a high need to increase it. In this embodiment, it is possible to secure the turning torque (particularly, the starting torque) of the upper swinging body by controlling the capacity of the swinging motor to adjust to the second capacity in such a case. To. On the other hand, when the inclination of the construction machine is equal to or greater than the inclination threshold value and the upper swing body is swivel in the swivel fall direction, the capacity of the swivel motor is increased even during the combined operation. The control for adjusting to the second capacity is not performed, but the control for adjusting the capacity of the swing motor to a capacity smaller than the second capacity is performed. This makes it possible to suppress the occurrence of cavitation in the swivel motor. In this embodiment, the capacity smaller than the second capacity may be the first capacity or a capacity different from the first capacity.

The construction machine has a differential pressure detecting unit for detecting a differential pressure between a hydraulic oil supply oil passage and a hydraulic oil return oil passage connected to the swivel motor, and the differential pressure detected by the differential pressure detecting unit. A torque calculation unit that calculates a provisional turning torque based on the second capacity and the second capacity, and the capacity control unit further includes a torque threshold value in which the provisional turning torque calculated by the torque calculation unit is preset. If it is less than, the provisional turning torque calculated by the torque calculation unit is the torque threshold value while controlling for adjusting the capacity of the turning motor to the second capacity at the time of the combined operation. In the above case, it is preferable that the control is performed so as to adjust the capacity of the swivel motor at the time of the combined operation to a capacity smaller than the second capacity.

In this aspect, when the provisional turning torque is equal to or higher than the torque threshold value, control for adjusting the capacity of the turning motor to the second capacity is not performed even during the combined operation, and the turning Control is performed to adjust the capacity of the motor to a capacity smaller than the second capacity. This can prevent the occurrence of overtorque. In this embodiment, the capacity smaller than the second capacity may be the first capacity or a capacity different from the first capacity.

As described above, according to the present invention, it is possible to suppress the occurrence of pressure loss during a combined operation in which the turning operation of the upper swing body and the attachment operation are simultaneously performed by the hydraulic oil discharged from the common hydraulic pump. However, a construction machine capable of suppressing a delay in the turning operation of the upper turning body is provided.

It is a side view which shows the construction machine which concerns on embodiment of this invention. It is the schematic which shows the grapple which is an example of the tip attachment attached to the tip of the arm of the construction machine. It is the schematic which shows the crusher which is an example of the tip attachment attached to the tip of the arm of the construction machine. It is the schematic which shows the breaker which is an example of the tip attachment attached to the tip of the arm of the construction machine. It is the schematic which shows the fork which is an example of the tip attachment attached to the tip of the arm of the construction machine. It is a figure which shows the hydraulic circuit in the said construction machine. It is a block diagram which shows the functional structure of the control device in the construction machine and the input / output signal thereof. It is a flowchart which shows the arithmetic control operation of the control device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a construction machine 100 according to an embodiment of the present invention. As shown in FIG. 1, the construction machine 100 has a crawler-type lower traveling body 1 constituting a base body and a lower traveling body 1 so as to be able to turn around a turning central axis Z perpendicular to the running surface thereof. An upper swivel body 2 mounted on the upper swivel body 2 and an attachment 3 mounted on the upper swivel body 2 are provided.

The attachment 3 includes a boom 4 undulatingly supported by the upper swing body 2, an arm 5 rotatably connected to the tip of the boom 4, and a plurality of tip attachments. The plurality of tip attachments include the tip attachment 6 (bucket 6) shown in FIG. 1 and the tip attachments 6A to 6D shown in FIGS. 2 to 5. Any one of the plurality of tip attachments is selectively detachably connected to the tip portion of the arm 5.

The tip attachment 6A shown in FIG. 2 is a grapple 6A for gripping and transporting scrap in, for example, a scrap yard. The grapple 6A includes a bracket 61A attached to the tip of the arm 5, a grapple body 62A supported by the bracket 61A, and a plurality of claws 63A (four claws 63A in FIG. 2) supported by the grapple body 62A. To be equipped with.

The tip attachment 6B shown in FIG. 3 is a crusher 6B for performing dismantling work of, for example, a concrete structure. The crusher 6B includes a bracket 61B attached to the tip of the arm 5, a crusher main body 62B supported by the bracket 61B, and a pair of crushing arms 63B supported by the crusher main body 62B.

The tip attachment 6C shown in FIG. 4 is a breaker 6C for use, for example, for excavating rock, breaking rock into small pieces, and crushing concrete. The breaker 6C includes a bracket 61C attached to the tip of the arm 5, a breaker main body 62C supported by the bracket 61C, and a chisel 63C supported by the breaker main body 62C and capable of reciprocating in the axial direction thereof.

The tip attachment 6D shown in FIG. 5 is, for example, a fork 6D for gripping a transported object. The fork 6D includes a bracket 61D attached to the tip of the arm 5, a fork body 62D supported by the bracket 61D, and a pair of opening / closing arms 63D supported by the fork body 62D.

FIG. 6 is a diagram showing a hydraulic circuit in the construction machine 100. FIG. 7 is a block diagram showing a functional configuration of the control device 70 in the construction machine 100 and its input / output signals. As shown in FIGS. 6 and 7, the construction machine 100 includes an engine 20, a first hydraulic pump 21, a second hydraulic pump 22, a pilot pump 23, a swivel motor 30, and a plurality of actuators. , A swivel control valve 41, a plurality of attachment control valves, a swivel operation device 81, a plurality of attachment operation devices, a plurality of detection units, and a control device 70. The plurality of attachment control valves include an arm control valve 42, an option control valve 43, a boom control valve (not shown), and a tip attachment control valve (not shown). The plurality of attachment operating devices include an arm operating device 82, an optional operating device 83, a boom operating device (not shown), and a tip attachment operating device (not shown).

Each of the first hydraulic pump 21 and the second hydraulic pump 22 is a variable displacement hydraulic pump in which the pump capacity can be adjusted. Each of these hydraulic pumps 21 and 22 has a regulator (not shown), and the regulator changes the pump capacity to a capacity corresponding to the capacity command signal by receiving an input of a capacity command signal from the control device 70. Adjust. Each of the first hydraulic pump 21, the second hydraulic pump 22, and the pilot pump 23 is driven by the engine 20, thereby discharging the hydraulic oil in the tank (not shown).

The swivel motor 30 is a hydraulic motor for swiveling and driving the upper swivel body 2. The swivel motor 30 has an output shaft (not shown) that rotates in response to the supply of hydraulic oil discharged from the first hydraulic pump 21, and the output shaft swivels the upper swivel body 2 in both left and right directions. Is connected to the upper swivel body 2. Specifically, the swivel motor 30 has a first port 30a and a second port 30b, and by receiving the supply of hydraulic oil to one of these ports, the direction corresponding to the one port is described. As the output shaft rotates, hydraulic oil is discharged from the other port. The swivel motor 30 is a variable displacement hydraulic motor whose motor capacitance can be adjusted. The swivel motor 30 has a regulator (not shown), and the regulator adjusts the motor capacity to a capacity corresponding to the capacity command signal by receiving an input of a capacity command signal from the control device 70.

As shown in FIG. 1, the plurality of actuators rotate a boom cylinder 7 that operates to undulate the boom 4 with respect to the upper swing body 2 and an arm 5 with respect to the boom 4. An arm cylinder 8 that operates so as to rotate, a tip attachment cylinder 9 that operates so as to rotate the tip attachment (bucket 6 in FIG. 1) with respect to the arm 5, and an optional cylinder 10 (see FIG. 6). ,including.

As shown in FIG. 6, each of the arm cylinder 8 and the option cylinder 10 operates by receiving the supply of hydraulic oil discharged from the same hydraulic pump as the first hydraulic pump 21 that swivels and drives the swivel motor 30. It is configured to do. That is, the swivel motor 30, the arm cylinder 8, and the option cylinder 10 are connected to a common first hydraulic pump 21. On the other hand, although not shown in FIG. 6, each of the boom cylinder 7 and the tip attachment cylinder 9 is configured to operate by receiving the supply of hydraulic oil discharged from the second hydraulic pump 22. Has been done.

The arm cylinder 8 has a bottom chamber 8a and a rod chamber 8b on the opposite side thereof. The arm cylinder 8 is extended by supplying hydraulic oil to the bottom chamber 8a to move the arm 5 in one direction and discharge hydraulic oil from the rod chamber 8b, and conversely to the rod chamber 8b. When the hydraulic oil is supplied, the arm 5 contracts to move in the other direction, and the hydraulic oil is discharged from the bottom chamber 8a.

The option cylinder 10 shown in FIG. 6 is an actuator different from the tip attachment cylinder 9 shown in FIG. 1 and is for causing an operation peculiar to each of the tip attachments 6A to 6D shown in FIGS. 2 to 5. Cylinder.

The option cylinder 10 has a bottom chamber 10a and a rod chamber 10b on the opposite side thereof. The option cylinder 10 extends by supplying hydraulic oil to the bottom chamber 10a to move a part of the tip attachment in one direction and discharges hydraulic oil from the rod chamber 10b, and conversely, the rod chamber. When the hydraulic oil is supplied to 10b, it contracts to move the part of the tip attachment in the other direction and discharge the hydraulic oil from the bottom chamber 10a. Specifically, it is as follows.

When the tip attachment is the grapple 6A shown in FIG. 2, the option cylinder 10 is provided on the grapple body 62A, for example, and operates so as to open and close a plurality of claws 63A. When the tip attachment is the crusher 6B shown in FIG. 3, the option cylinder 10 is provided on, for example, the crusher main body 62B, and operates so as to open and close the pair of crushing arms 63B. When the tip attachment is the breaker 6C shown in FIG. 4, the option cylinder 10 is provided in, for example, the breaker main body 62C, and causes the chisel 63C to move forward / backward (reciprocating) in the axial direction with respect to the breaker main body 62C. To operate. When the tip attachment is the fork 6D shown in FIG. 5, the option cylinder 10 is provided on, for example, the fork body 62D, and operates so as to open and close the pair of opening and closing arms 63D. The bucket 6 is not provided with the option cylinder 10 as described above.

The operating pressure required for each of the tip attachments 6A to 6D to perform the specific operation, that is, the operating pressure required for operating the option cylinder 10, differs depending on the type of the tip attachment. .. Of the tip attachments 6A to 6D, the grapple 6A and the fork 6D generally have a low working pressure, and the crusher 6B and the breaker 6C generally have a high working pressure.

As shown in FIG. 6, the swivel control valve 41 is interposed between the first hydraulic pump 21 and the swivel motor 30. The swivel control valve 41 selectively guides hydraulic oil for driving the swivel motor 30 from the first hydraulic pump 21 to any of the first and second ports 30a and 30b of the swivel motor 30. At the same time, the swing flow rate, which is the flow rate of the hydraulic oil supplied to the swing motor 30, is controlled. The swivel control valve 41 is a pilot switching valve at three positions, and has a pair of swivel pilot ports (a swivel pilot port on the opposite side of one swivel pilot port P1).

The swivel control valve 41 is maintained in a neutral position when the pilot pressure supplied to the pair of swivel pilot ports is 0 or very small, and is between the first hydraulic pump 21 and the swivel motor 30. And connect the center line L1 to the tank. When a certain amount of pilot pressure or more is supplied to any one of the pair of swivel pilot ports, the swivel control valve 41 is neutral with a stroke corresponding to the magnitude of the pilot pressure in the direction corresponding to the swivel pilot port. The turning supply line L11 that shifts from the position and branches from the center line L1 is connected to the first port 30a or the second port 30b, and the center line L1 is narrowed down to a degree corresponding to the stroke. The swivel motor 30 is operated in the direction and speed corresponding to the stroke.

The swivel control valve 41 and the first port 30a of the swivel motor 30 are connected by a first port line L41, and the swivel control valve 41 and the second port 30b of the swivel motor 30 are second. It is connected by port line L42. By shifting the swivel control valve 41 from the neutral position, one line of the first port line L41 and the second port line L42 functions as a hydraulic oil supply oil passage, and the other line functions as hydraulic oil. Functions as a return oil passage.

The arm control valve 42 is interposed between the first hydraulic pump 21 and the arm cylinder 8. The arm control valve 42 selectively guides hydraulic oil for driving the arm cylinder 8 from the first hydraulic pump 21 to either the bottom chamber 8a or the rod chamber 8b of the arm cylinder 8. , The arm flow rate, which is the flow rate of the hydraulic oil supplied to the arm cylinder 8, is controlled. The arm control valve 42 is a pilot switching valve at three positions, and has a pair of arm pilot ports (an arm pilot port on the opposite side of one arm pilot port P2).

The arm control valve 42 is maintained in a neutral position when the pilot pressure supplied to the pair of arm pilot ports is 0 or minute, and is between the first hydraulic pump 21 and the arm cylinder 8. And connect the center line L2 to the tank. When a certain amount of pilot pressure or more is supplied to any of the pair of arm pilot ports, the arm control valve 42 shifts from the neutral position with a stroke corresponding to the magnitude of the pilot pressure, and from the center line L2. The branching arm supply line L21 is connected to the bottom chamber 8a or the rod chamber 8b, and the center line L2 is throttled to a degree corresponding to the stroke, whereby the arm cylinder 8 is oriented in the direction corresponding to the stroke and Operate at speed.

The option control valve 43 is interposed between the first hydraulic pump 21 and the option cylinder 10. The option control valve 43 selectively guides hydraulic oil for driving the option cylinder 10 from the first hydraulic pump 21 to either the bottom chamber 10a or the rod chamber 10b of the option cylinder 10. , The option flow rate, which is the flow rate of the hydraulic oil supplied to the option cylinder 10, is controlled. The option control valve 43 is a pilot switching valve at three positions, and has a pair of option pilot ports (one option pilot port P3 and an optional pilot port shown on the opposite side).

The option control valve 43 is maintained in a neutral position when the pilot pressure supplied to the pair of option pilot ports is 0 or very small, and is between the first hydraulic pump 21 and the option cylinder 10. And connect the center line L3 to the tank. When a certain level or more of pilot pressure is supplied to any of the pair of option pilot ports, the option control valve 43 shifts from the neutral position with a stroke corresponding to the magnitude of the pilot pressure, and from the center line L3. The branching option supply line L31 is connected to the bottom chamber 10a or the rod chamber 10b, and the center line L3 is throttled to a degree corresponding to the stroke, whereby the option cylinder 10 is oriented in the direction corresponding to the stroke and Operate at speed.

The boom control valve is interposed between the second hydraulic pump 22 and the boom cylinder 7, controls the direction of hydraulic oil supplied to the boom cylinder 7, and is supplied to the boom cylinder 7. It is a control valve for controlling the flow rate of hydraulic oil. The tip attachment control valve is interposed between the second hydraulic pump 22 and the tip attachment cylinder 9, controls the direction of hydraulic oil supplied to the tip attachment cylinder 9, and controls the direction of the hydraulic oil supplied to the tip attachment cylinder 9. It is a control valve for controlling the flow rate of hydraulic oil supplied to the cylinder.

The swivel operation device 81 receives a swivel operation for moving the swivel motor 30, and a pilot pressure corresponding to the swivel operation is applied from the pilot pump 23 to any of the pair of swivel pilot ports of the swivel control valve 41. Operates to allow an alternative supply. Specifically, the swivel operation device 81 is located between the swivel operation lever 81a, which is a swivel operation member capable of rotating in response to the swivel operation, and the pilot pump 23 and the pair of swivel pilot ports. It has an intervening swivel pilot valve 81b. The swivel pilot valve 81b closes when the swivel operation lever 81a is in the neutral position without being operated to shut off between the pilot pump 23 and the pair of swivel pilot ports, while the swivel operation lever 81a Is rotated from the neutral position to supply a pilot pressure of a magnitude corresponding to the amount of the rotation operation to the rotation pilot port corresponding to the direction of the rotation operation among the pair of rotation pilot ports. Open the valve as you do.

The arm operating device 82 receives an arm operation for moving the arm cylinder 8 (an example of an attachment operation in the present invention), and a pilot pressure corresponding to the arm operation is applied from the pilot pump 23 to the arm control valve 42. Operates to allow alternative supply to any of the pair of arm pilot ports. Specifically, the arm operating device 82 includes an arm operating lever 82a which is an arm operating member (an example of an attachment operating member in the present invention) capable of rotating in response to the arm operation, and the pilot pump 23. It has an arm pilot valve 82b interposed between the pair of arm pilot ports. The arm pilot valve 82b closes when the arm operating lever 82a is in the neutral position without being operated to shut off between the pilot pump 23 and the pair of arm pilot ports, while the arm operating lever 82a Is rotated from the neutral position to supply a pilot pressure of a magnitude corresponding to the amount of the rotation operation to the arm pilot port corresponding to the direction of the rotation operation among the pair of arm pilot ports. Open the valve as you do.

The option operation device 83 receives an option operation for moving the option cylinder 10 (an example of an attachment operation in the present invention), and a pilot pressure corresponding to the option operation is applied from the pilot pump 23 to the option control valve 43. Operates to allow alternative supply to any of the pair of optional pilot ports. Specifically, the option operation device 83 includes an option operation lever 83a which is an option operation member (an example of an attachment operation member in the present invention) capable of rotating in response to the option operation, and the pilot pump 23. It has an optional pilot valve 83b interposed between the pair of optional pilot ports. The option pilot valve 83b closes when the option operating lever 83a is in the neutral position without being operated to shut off between the pilot pump 23 and the pair of option pilot ports, while the option operating lever 83a Is rotated from the neutral position to supply a pilot pressure of a magnitude corresponding to the amount of the rotation operation to the option pilot port corresponding to the direction of the rotation operation among the pair of option pilot ports. Open the valve as you do. The turning operation device 81, the arm operation device 82, and the option operation device 83 may have a pedal-type operation member (operation pedal).

As shown in FIG. 7, the plurality of detection units include a swivel speed detection unit 90, a discharge pressure detection unit 91, an inclination detection unit 92, a differential pressure detection unit 93, a swivel operation direction detection unit 94, and an arm. It includes an operation direction detection unit 95 and an optional operation direction detection unit 96. An electric signal corresponding to the detected value detected by the plurality of detection units is input to the control device 70.

The turning speed detection unit 90 is a sensor for detecting the rotation speed of the turning motor 30 as a turning speed. The turning speed detection unit 90 detects the turning speed, converts it into a turning detection signal which is an electric signal, and inputs the detection signal to the control device 70. Specifically, the turning speed detection unit 90 converts the detected turning speed magnitude, turning direction, and the like of the upper turning body 2 into a turning detection signal which is an electric signal, and inputs it to the control device 70. As the turning speed detecting unit 90, for example, a turning speed sensor such as a gyro sensor, an encoder, or a resolver can be used, but the turning speed sensor 90 is not limited thereto.

The discharge pressure detection unit 91 is a pressure sensor, detects the discharge pressure of the hydraulic pump 21, converts the discharge pressure detection signal into an electric signal, and inputs the detection signal to the control device 70.

The discharge pressure detection unit 91 requires a relatively small operating pressure to drive the discharge pressure detection unit 91 during a combined operation in which a swivel operation for operating the swivel motor 30 and an arm pull operation for extending the arm cylinder 8 are performed at the same time. A discharge pressure that is substantially equal to the operating pressure for extending the arm cylinder 8 is detected.

At the time of a combined operation in which the swivel operation for operating the swivel motor 30 and the optional operation for extending the option cylinder 10 are performed at the same time, the discharge pressure detection unit 91 and the operating pressure required to operate the swivel motor 30 Detects a discharge pressure that is approximately equal to any of the working pressures required to extend the option cylinder 10. When the operating pressure required to extend the option cylinder 10 is larger than the operating pressure required to operate the swivel motor 30, the discharge pressure detecting unit 91 operates the swivel motor 30. Detects a discharge pressure that is approximately equal to the required operating pressure. When the operating pressure required to extend the option cylinder 10 is smaller than the operating pressure required to operate the swing motor 30, the discharge pressure detecting unit 91 extends the option cylinder 10. Detects a discharge pressure that is approximately equal to the required operating pressure.

During the combined operation of simultaneously performing the swivel operation for operating the swivel motor 30, the arm pulling operation for extending the arm cylinder 8, and the optional operation for extending the option cylinder 10, the discharge pressure detecting unit 91 is the arm cylinder. A discharge pressure that is approximately equal to the smaller of the operating pressure required to extend the 8 and the operating pressure required to extend the option cylinder 10 is detected.

The discharge pressure detection unit 91 is provided, for example, in the pump line L0 that connects the first hydraulic pump 21 and the center lines L1, L2, and L3. However, the portion of the hydraulic circuit where the discharge pressure detecting unit 91 is provided may be a position where the discharge pressure of the hydraulic pump 21 can be detected, and is not limited to the pump line L0 but may be a line L1 or a line L2.

The inclination detection unit 92 is an inclination sensor for detecting the inclination (inclination of the vehicle body) of the upper swing body 2 of the construction machine 100. The inclination detection unit 92 is attached to, for example, the upper swing body 2 (specifically, for example, the upper frame of the upper swing body 2). Specifically, as the tilt detection unit 92, for example, a biaxial tilt sensor capable of measuring tilt in two directions can be used. The biaxial tilt sensor measures, for example, the tilt of the upper swivel body 2 with respect to the X-axis direction and the tilt of the upper swivel body 2 with respect to the Y-axis direction, and the upper swivel body 2 with respects the horizontal plane based on these measurement results. It is possible to detect how it is tilted. As the biaxial tilt sensor, a known tilt sensor such as a tilt sensor that measures the gravitational acceleration and detects the tilt can be applied. The inclination detection unit 92 detects the inclination of the upper swing body 2, converts it into an inclination detection signal which is an electric signal, and inputs the detection signal to the control device 70.

The differential pressure detecting unit 93 is a pressure sensor that detects the differential pressure (effective differential pressure) in the swivel motor 30. Specifically, the differential pressure detection unit 93 includes a first port pressure sensor 93a and a second port pressure sensor 93b. The first port pressure sensor 93a detects a first port pressure (MA), which is the pressure of hydraulic oil in the first port 30a of the swivel motor 30, and an electric signal corresponding to the first port pressure. It is a pressure sensor that generates a first port pressure detection signal. The second port pressure sensor 93b detects a second port pressure (MB), which is the pressure of hydraulic oil in the second port 30b of the swivel motor 30, and an electric signal corresponding to the second port pressure. It is a pressure sensor that generates a second port pressure detection signal. These port pressure detection signals are input to the control device 70. The first port pressure sensor 93a is provided, for example, in the first port line L41, and the second port pressure sensor 93b is provided, for example, in the second port line L42.

The turning operation direction detection unit 94 is composed of a pair of turning pilot pressure sensors (a pair of pressure sensors). Of the pair of swivel pilot pressure sensors, one swivel pilot pressure sensor 94a detects the swivel pilot pressure of the hydraulic oil supplied from the swivel remote control valve 81b to the one swivel pilot port P1 in the swivel control valve 41. , This is converted into a turning pilot pressure detection signal which is an electric signal, and the detection signal is input to the control device 70. Of the pair of swivel pilot pressure sensors, the other swivel pilot pressure sensor (not shown) is a swivel pilot of hydraulic oil supplied from the swivel remote control valve 81b to the other swivel pilot port of the swivel control valve 41 (not shown). The pressure is detected, this is converted into a turning pilot pressure detection signal which is an electric signal, and the detection signal is input to the control device 70.

The arm operation direction detection unit 95 is composed of a pair of arm pilot pressure sensors (a pair of pressure sensors). Of the pair of arm pilot pressure sensors, one arm pilot pressure sensor 95a detects the arm pilot pressure of hydraulic oil supplied from the arm remote control valve 82b to the one arm pilot port P2 in the arm control valve 42. , This is converted into an arm pilot pressure detection signal which is an electric signal, and the detection signal is input to the control device 70. Of the pair of arm pilot pressure sensors, the other arm pilot pressure sensor shown in the drawing is an arm pilot of hydraulic oil supplied from the arm remote control valve 82b to the other arm pilot port shown in the arm control valve 42. The pressure is detected, this is converted into an arm pilot pressure detection signal which is an electric signal, and the detection signal is input to the control device 70.

The optional operation direction detection unit 96 is composed of a pair of optional pilot pressure sensors (a pair of pressure sensors). Of the pair of optional pilot pressure sensors, one of the optional pilot pressure sensors 96a detects the optional pilot pressure of the hydraulic oil supplied from the optional remote control valve 83b to the one optional pilot port P3 of the optional control valve 43. , This is converted into an optional pilot pressure detection signal which is an electric signal, and the detection signal is input to the control device 70. Of the pair of optional pilot pressure sensors, the other optional pilot pressure sensor (not shown) is an optional pilot of hydraulic oil supplied from the optional remote control valve 83b to the other optional pilot port of the optional control valve 43 (not shown). The pressure is detected, this is converted into an optional pilot pressure detection signal which is an electric signal, and the detection signal is input to the control device 70.

As shown in FIG. 6, the construction machine 100 further includes a discharge pressure detecting unit 97, and the discharge pressure detecting unit 97 detects the discharge pressure of the second hydraulic pump 22 to detect the second discharge pressure. This is a pressure sensor for detecting an operating pressure (operating pressure of another actuator included in the construction machine 100) that is equal to the discharge pressure of the hydraulic pump 22 of the above. Examples of the other actuator include, but are not limited to, the boom cylinder 7.

As shown in FIG. 7, the control device 70 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) for storing various control programs, a RAM (Random Access Memory) used as a work area of the CPU, and the like. Consists of.

The control device 70 includes a capacitance control unit 71, a torque calculation unit 72, a torque determination unit 73, a discharge pressure determination unit 74, an operation determination unit 75, a turning brake determination unit 76, an inclination determination unit 77, and the like. It is provided with a turning speed determination unit 78 as a function. The control device 70 operates so that the CPU executes the control program based on the electric signals input from the plurality of detection units and the like so that they are functionally configured.

The capacity control unit 71 controls to adjust the capacity of the swivel motor 30 to a preset first capacity at the time of a swivel independent operation in which the swivel operation is performed but the attachment operation is not performed. In the combined operation in which the swivel operation and the attachment operation are performed at the same time, in principle, control for adjusting the capacity of the swivel motor 30 to a second capacity larger than the first capacity is performed. It is configured to do. The function of the capacity control unit 71 will be described in detail later.

The torque calculation unit 72 calculates the provisional turning torque based on the differential pressure detected by the differential pressure detection unit 93 and the second capacitance. The provisional turning torque is used for the purpose of preventing the occurrence of overtorque before the capacity control unit 71 changes the capacity of the turning motor 30 from the first capacity to the second capacity. The turning torque is tentatively calculated based on the differential pressure in the swing motor 30 and the second capacitance. The torque calculation unit 72 calculates the provisional turning torque based on, for example, the following equation (1).

Temporary turning torque = (the second capacity x the differential pressure) / 2π x the efficiency of the turning motor ... (1)
The torque determination unit 73 determines whether or not the provisional turning torque calculated by the torque calculation unit 72 is less than a preset torque threshold value. The torque threshold value is set based on, for example, the allowable torque of the speed reducer.

The discharge pressure determination unit 74 determines whether or not the discharge pressure detected by the discharge pressure detection unit 91 is less than a preset discharge pressure threshold value.

The operation determination unit 75 determines whether or not the turning independent operation has been performed. In addition, the operation determination unit 75 determines whether or not the combined operation has been performed. Specifically, the operation determination unit 73 determines whether or not the rotation operation has been performed based on the rotation pilot pressure detection signal detected by the rotation operation direction detection unit 94, and the arm operation direction detection unit 73. It is determined whether or not the arm operation has been performed based on the arm pilot pressure detection signal detected by 95, and the option operation is performed based on the option pilot pressure detection signal detected by the option operation direction detection unit 96. Is determined whether or not has been performed. When the operation determination unit 75 determines that the turning operation has been performed and that neither the arm operation nor the optional operation has been performed, it is determined that the turning independent operation has been performed. To do. When the operation determination unit 75 determines that the turning operation has been performed and at least one of the arm operation and the option operation has been performed, it determines that the combined operation has been performed.

The turning brake determination unit 76 determines whether or not the brake is not applied to the turning of the upper turning body 2. Specifically, when the turning brake determination unit 76 is in the neutral position, for example, when the position of the turning operation lever 81a based on the turning pilot pressure detection signal detected by the turning operation direction detecting unit 94 is in the neutral position. It can be determined that the brake is applied to the turning of the upper turning body 2. Further, for example, whether the turning brake determination unit 76 is braking the turning of the upper turning body 2 based on the differential pressure in the turning motor 30 detected by the differential pressure detecting unit 93. Alternatively, it can be determined whether the upper swing body 2 is accelerating.

The inclination determination unit 77 determines whether or not the inclination (inclination of the vehicle body) of the upper swing body 2 of the construction machine 100 is less than a preset inclination threshold value D based on the detection signal detected by the inclination detection unit 92. Is determined. Further, in the tilt determination unit 77, the turning direction of the upper swing body 2 is the turning fall direction based on the detection signal detected by the tilt detection unit 92 and the detection signal detected by the turning operation direction detection unit. Judge that there is no such thing.

The turning speed determination unit 78 determines whether or not the turning speed is less than a preset speed threshold value based on the detection signal detected by the turning speed detection unit 90.

FIG. 8 is a flowchart showing a calculation control operation of the control device 70 of the construction machine 100 according to the embodiment.

The control device 70 reads various detection signals input to the control device 70 (step S1). The discharge pressure determination unit 74 of the control device 70 determines whether or not the discharge pressure is less than the discharge pressure threshold value A (step S2). When the discharge pressure is equal to or higher than the discharge pressure threshold value A (NO in step S2), the capacity control unit 71 does not need to control the capacity of the swing motor to the second capacity. Control is performed to adjust (maintain) the capacity of the swivel motor 30 to the first capacity (step S10). Specifically, when the swivel motor 30 is, for example, a swash plate type hydraulic motor, the swash plate is set to a small tilt position corresponding to, for example, the first capacity.

As described above, among the tip attachments 6A to 6D, the grapple 6A and the fork 6D generally have a low operating pressure, and the crusher 6B and the breaker 6C generally have a high operating pressure. Therefore, the crusher 6B or the breaker 6C is connected to the tip of the arm 5, and the hydraulic oil discharged from the first hydraulic pump 21 is supplied to the option cylinder 10 to supply the crusher 6B or the breaker 6C. When the breaker 6C is operating, the discharge pressure tends to be equal to or higher than the discharge pressure threshold value A. When the discharge pressure is equal to or higher than the discharge pressure threshold value A, the starting torque can be secured, so that control for adjusting the capacity of the swing motor to the second capacity becomes unnecessary. On the other hand, when the grapple 6A or the fork 6D is connected to the tip of the arm 5, even if the grapple 6A or the fork 6D is operating, the discharge pressure is less than the discharge pressure threshold value A. Therefore, in order to secure the starting torque, control for adjusting the capacity of the swing motor to the second capacity is required.

When the discharge pressure is less than the discharge pressure threshold value A (YES in step S2), the operation determination unit 75 determines whether or not the turning operation has been performed based on the turning pilot pressure detection signal (YES in step S2). Step S3). When the turning pilot pressure is less than the preset turning pilot pressure threshold value B (NO in step S3), the operation determination unit 75 determines that the turning operation has not been performed. In such a case, since the combined operation is not performed, the capacity control unit 71 controls to adjust (maintain) the capacity of the swing motor to the first capacity (step S10).

When the turning pilot pressure is equal to or higher than the turning pilot pressure threshold value B (YES in step S3), the operation determination unit 75 determines that the turning operation has been performed. In such a case, the torque calculation unit 72 calculates the provisional turning torque based on the differential pressure detected by the differential pressure detection unit 93 and the second capacitance, and the torque determination unit 73 calculates the torque. It is determined whether or not the provisional turning torque calculated by the unit 72 is less than the preset torque threshold C (step S4). When the provisional turning torque is equal to or higher than the torque threshold value C (NO in step S4), the capacity control unit 71 sets the capacity of the turning motor to the first capacity in order to prevent the occurrence of overtorque. Control for adjusting (maintaining) to (step S10).

When the provisional turning torque is less than the torque threshold value C (YES in step S4), whether or not the turning brake determination unit 76 is in a state in which the turning of the upper turning body 2 is not braked. Is determined (step S5). When the brake is applied to the turning of the upper turning body 2 (NO in step S5), that is, when the turning is decelerating, the capacity of the turning motor is adjusted to the second capacity. Since no control is required, the capacitance control unit 71 controls to adjust (maintain) the capacitance of the swing motor 30 to the first capacitance (step S10).

When the brake is not applied to the turning of the upper turning body 2 (YES in step S5), that is, when the turning is not decelerated, the inclination determination unit 77 makes the following determination. That is, the inclination determination unit 77 determines whether or not the inclination (inclination of the vehicle body) of the upper swing body 2 is less than the preset inclination threshold value D based on the detection signal detected by the inclination detection unit 92. Determine (step S6). Further, in the tilt determination unit 77, the turning direction of the upper swing body 2 is the turning fall direction based on the detection signal detected by the tilt detection unit 92 and the detection signal detected by the turning operation direction detection unit. It is determined that there is no such thing (step S6). Here, the fact that the turning direction is not the turning and falling direction means that the turning direction is a horizontal direction and that the turning direction is a direction opposite to the turning and falling direction (that is, an ascending direction). including. When the inclination of the upper swing body 2 is equal to or higher than the tilt threshold value D and the swing direction of the upper swing body 2 is the swing fall direction (NO in step S6), cavitation is generated in the swing motor 30. In order to prevent this from happening, the capacity control unit 71 controls to adjust (maintain) the capacity of the swing motor 30 to the first capacity (step S10).

When the inclination of the upper swivel body 2 is less than the tilt threshold value D, or when the swivel direction of the upper swivel body 2 is not the swivel fall direction (YES in step S6), the swivel speed determination unit 78 said. Based on the detection signal detected by the turning speed detection unit 90, it is determined whether or not the turning speed is less than the preset speed threshold value E (step S7). When the turning speed is equal to or higher than the speed threshold value E (NO in step S7), control for adjusting the capacity of the turning motor to the second capacity is unnecessary, so that the capacity control unit 71 is said to have the same. Control is performed to adjust (maintain) the capacity of the swing motor 30 to the first capacity (step S10).

The case where YES is determined in step S6 means that the inclination of the upper swivel body 2 is less than the tilt threshold value D, and that the swivel direction of the upper swivel body 2 is not the swivel fall direction. This is the case when at least one of the conditions is satisfied.

When the turning speed is less than the speed threshold value E (YES in step S7), the operation determination unit 75 operates the arm and operates the option based on the arm pilot pressure detection signal and the option pilot pressure detection signal. It is determined whether or not at least one of the above has been performed (step S8). When the arm pilot pressure is less than the preset arm pilot pressure threshold value F and the option pilot pressure is less than the preset option pilot pressure threshold value G (NO in step S8), the operation determination unit 75 Determines that neither the arm operation nor the option operation is performed. In such a case, since the combined operation is not performed, the capacity control unit 71 controls to adjust (maintain) the capacity of the swing motor to the first capacity (step S10).

When the arm pilot pressure is equal to or higher than the arm pilot pressure threshold value F, or when the optional pilot pressure is equal to or higher than the optional pilot pressure threshold value G (YES in step S8), the operation determination unit 75 performs the turning operation. It is determined that a combined operation in which at least one of the arm operation and the option operation is performed at the same time is being performed. In such a case, the capacity control unit 71 controls to adjust the capacity of the swing motor 30 to the second capacity larger than the first capacity (step S9). Specifically, when the swivel motor 30 is, for example, a swash plate type hydraulic motor, the swash plate is set to a large tilt position corresponding to, for example, the second capacity. After that, the control device 70 repeats the processes of steps S1 to S10 described above.

The case where YES is determined in step S8 is a condition that the arm pilot pressure is equal to or higher than the arm pilot pressure threshold value F and a condition that the optional pilot pressure is equal to or higher than the option pilot pressure threshold value G. This is the case when at least one of the conditions is satisfied.

As described above, in the construction machine 100 according to the embodiment, the capacity of the swivel motor 30 at the time of the combined operation is adjusted to the second capacity which is larger than the capacity of the swivel motor 30 at the time of the swivel single operation. To. This means that the turning torque for turning the upper swivel body 2 without or limiting the control of reducing the amount of oil to the cylinder accompanied by the occurrence of the pressure loss as in the conventional case, particularly, It is possible to secure a starting torque for starting the turning of the upper turning body 2. As a result, the output of the first hydraulic pump 21 can be efficiently transmitted to the swivel motor 30, the arm cylinder 8, and the option cylinder 10 while suppressing the occurrence of unnecessary pressure loss. On the other hand, during the turning independent operation, the capacity of the turning motor is adjusted to the first capacity, so that the occurrence of the overtorque is suppressed.

Further, the construction machine 100 according to the embodiment has a capacity of the swivel motor 30 when the swivel speed is less than the speed threshold value, that is, when it is highly necessary to increase the starting torque during the combined operation. Is increased to make it possible to secure the starting torque. On the other hand, when the turning speed is equal to or higher than the speed threshold value during the combined operation, that is, when there is little need to increase the turning torque even during the combined operation, the capacity of the turning motor 30 is increased. Control is performed to adjust to the first capacitance. This means that the decrease in the maximum speed of turning due to the capacity of the turning motor 30 being adjusted to the second capacity is suppressed, and the maximum speed equivalent to the maximum speed of turning in the single operation of turning is achieved. Make it possible to secure.

In the construction machine 100 according to the embodiment, when the discharge pressure is less than the discharge pressure threshold value, that is, when it is highly necessary to increase the turning torque (particularly, the starting torque) during the combined operation, It is possible to increase the capacity of the swivel motor 30 to secure the swivel torque. On the other hand, when the discharge pressure is equal to or higher than the discharge pressure threshold value during the combined operation, that is, when the turning torque is secured even during the combined operation, the capacity of the swing motor 30 is used. Control is performed to adjust to the first capacitance. This suppresses a decrease in the maximum speed of turning due to the capacity of the turning motor being adjusted to the second capacity, and secures a maximum speed equivalent to the maximum speed of turning at the time of the single operation of turning. Allows you to.

The construction machine 100 according to the embodiment has the same pressure loss as the conventional one even when the operating pressure of the arm is low during the combined operation of the turning operation and the arm operation for operating the arm. It is possible to secure the turning torque (particularly the starting torque) while making it possible to suppress the generation.

The construction machine 100 according to the embodiment is the same as the conventional one even when the operating pressure of the tip attachment is low at the time of the combined operation of the turning operation and the tip attachment operation for operating the tip attachment. It is possible to secure the turning torque (particularly the starting torque) while making it possible to suppress the occurrence of the pressure loss.

In the construction machine 100 according to the embodiment, if the inclination of the upper swing body 2 of the construction machine 100 is less than the tilt threshold value or the upper swing body 2 is not swivel in the swivel fall direction, the above. Since it is unlikely that cavitation will occur in the swivel motor 30, control is performed to adjust the capacity of the swivel motor 30 to the second capacity during the combined operation. In particular, when the upper swivel body 2 swivels in a direction opposite to the swivel fall direction, that is, in a direction against gravity during the combined operation, the swivel torque (particularly, the starting torque) during the combined operation. There is a high need to increase. In such a case, the construction machine 100 according to the embodiment is controlled to adjust the capacity of the swivel motor 30 to the second capacity, so that the swivel torque (particularly, the start torque) of the upper swivel body 2 is performed. ) Can be secured. On the other hand, when the inclination of the upper swing body 2 of the construction machine 100 is equal to or greater than the tilt threshold value and the upper swing body 2 is swivel in the swivel fall direction, even during the combined operation. Control is performed to adjust the capacity of the swivel motor 30 to the first capacity. This makes it possible to suppress the occurrence of cavitation in the swivel motor 30.

In the construction machine 100 according to the embodiment, when the provisional turning torque is equal to or higher than the torque threshold value, the control for adjusting the capacity of the turning motor 30 to the first capacity is performed even during the combined operation. Will be done. This can prevent the occurrence of overtorque.

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

A) Motor capacity In the embodiment, when NO in each of steps S2 to S8, control is performed to adjust the capacity of the swivel motor 30 to the first capacity, but the present invention is not limited to this. That is, when NO in each of steps S2 to S8, control is performed to adjust the capacity of the swing motor 30 to a capacity smaller than the second capacity and different from the first capacity. You may be broken.

B) About the turning speed detection unit and the turning speed determination unit In the above-described embodiment, the construction machine 100 includes a turning speed detection unit and a turning speed determination unit, but these can be omitted.

C) Discharge pressure detection unit and discharge pressure determination unit In the above embodiment, the construction machine 100 includes a discharge pressure detection unit and a discharge pressure determination unit, but these can be omitted.

D) Inclination detection unit and inclination determination unit In the construction machine 100 according to the embodiment, when there is a risk of cavitation occurring, that is, when the construction machine 100 is arranged on an inclined ground having a predetermined inclination or more. Uniformly, even during the combined operation, the control for adjusting the capacity of the swivel motor 30 to the second capacity is not performed, and the capacity of the swivel motor 30 is reduced to a capacity smaller than the second capacity. Control to adjust may be performed. This makes it possible to suppress the occurrence of the cavitation caused by the inclination of the upper swing body 2 of the construction machine 100.

In the embodiment, the construction machine 100 includes an inclination detection unit and an inclination determination unit, but these can be omitted.

E) Differential pressure detection unit and torque calculation unit In the above embodiment, the construction machine 100 includes a differential pressure detection unit and a torque calculation unit, but these can be omitted.

F) Commonly for hydraulic pumps The first hydraulic pump 21 according to the embodiment is used for driving the swivel motor 30, the arm cylinder 8, and the option cylinder 10. The first hydraulic pump according to the present invention may be used for both driving the swivel motor 30 and driving the boom cylinder 7, for example, and is also used for driving the tip attachment cylinder 9. It may be.

G) Substrate In the above embodiment, the lower traveling body 1 is used as the substrate, but the substrate is not limited to the one that can travel like the lower traveling body 1, and is installed at a specific place to be an upper rotating body. It may be a base supporting 2.

H) Tip attachment In the above embodiment, grapples, crushers, breakers and forks have been exemplified as replaceable tip attachments, but the present invention is not limited thereto.

I) Flow chart In the flowchart showing the arithmetic control operation of the control device 70 shown in FIG. 8, reading of various signals (step S1), determination of presence / absence of turning operation (step S3), determination of presence / absence of arm operation and option operation (step S8). , The capacity of the swivel motor 30 is changed to the second capacity (step S9), and the capacity of the swivel motor 30 is maintained at the first capacity (step S10), but steps other than the above must be included. There is no. Steps other than the above can be incorporated into the arithmetic control operation as needed.

1 Lower running body (an example of a substrate)
2 Upper swivel body 3 Attachment 4 Boom 5 Arm 6 Bucket (Example of tip attachment)
6A grapple (an example of tip attachment)
6B crusher (example of tip attachment)
6C breaker (an example of tip attachment)
6D fork (an example of tip attachment)
8 Arm cylinder 10 Optional cylinder 21 1st hydraulic pump 22 2nd hydraulic pump 23 Pilot pump 30 Swivel motor 70 Control device 71 Capacity control unit 72 Torque calculation unit 81a Swivel operation lever (example of swivel operation member)
82a Arm operating lever (an example of attachment operating member)
83a Optional operation lever (an example of attachment operation member)
90 Swing speed detection unit 91 Discharge pressure detection unit 92 Tilt detection unit 93 Differential pressure detection unit 94 Swivel operation direction detection unit 95 Arm operation direction detection unit 96 Optional operation direction detection unit 100 Construction machinery L41 1st port line (hydraulic oil supply oil) Road or hydraulic oil return oil passage)
L42 2nd port line (hydraulic oil supply passage or hydraulic oil return oil passage)

Claims (8)

It ’s a construction machine,
With the substrate
An upper swivel body mounted on the substrate so as to be swivel,
The attachment mounted on the upper swing body and
A hydraulic pump that discharges hydraulic oil and
A variable displacement swivel motor that operates to swivel the upper swivel body by receiving the supply of the hydraulic oil discharged from the hydraulic pump.
An actuator that operates to operate at least a part of the attachment in response to the supply of the hydraulic oil discharged from the hydraulic pump.
A swivel operation member that receives a swivel operation for swiveling the upper swivel body,
An attachment operating member that receives an attachment operation for operating at least a part of the attachment,
At the time of the turning independent operation in which the turning operation is performed but the attachment operation is not performed, the turning operation is configured to control for adjusting the capacity of the turning motor to a preset first capacity. At the time of a combined operation in which the attachment operation and the attachment operation are performed at the same time, a capacitance control unit configured to control the capacitance of the swing motor to a second capacitance larger than the first capacitance. Prepare for construction machinery. The construction machine according to claim 1.
A swivel speed detection unit for detecting the swivel speed of the upper swivel body is further provided.
When the turning speed detected by the turning speed detecting unit is less than a preset speed threshold value, the capacity control unit adjusts the capacity of the turning motor at the time of the combined operation to the second capacity. On the other hand, when the turning speed detected by the turning speed detection unit is equal to or higher than the speed threshold value, the capacity of the turning motor at the time of the combined operation is larger than the capacity of the second capacity. Construction machinery that is configured to provide control for adjusting to smaller capacities. The construction machine according to claim 1 or 2.
A discharge pressure detection unit for detecting the discharge pressure of the hydraulic pump is further provided.
When the discharge pressure detected by the discharge pressure detection unit is less than a preset discharge pressure threshold value, the capacity control unit sets the capacity of the swing motor at the time of the combined operation to the second capacity. While performing control for adjustment, when the discharge pressure detected by the discharge pressure detection unit is equal to or higher than the discharge pressure threshold value, the capacity of the swivel motor at the time of the combined operation is changed to the second capacity. Construction machinery that is configured to perform controls to adjust to smaller capacities. The construction machine according to any one of claims 1 to 3.
The attachment includes a boom undulatingly supported by the upper swing body, an arm rotatably connected to the tip of the boom, and a tip attachment connected to the tip of the arm.
The actuator is an actuator that operates to operate the arm.
The attachment operation is an operation for operating the arm, which is a construction machine. The construction machine according to any one of claims 1 to 3.
The attachment includes a boom undulatingly supported by the upper swing body, an arm rotatably connected to the tip of the boom, and a tip attachment connected to the tip of the arm.
The actuator is an actuator that operates to operate the tip attachment.
The attachment operation is an operation for operating the tip attachment, which is a construction machine. The construction machine according to any one of claims 1 to 5.
Further equipped with an inclination detection unit for detecting the inclination of the construction machine,
When the inclination of the construction machine detected by the inclination detection unit is less than a preset inclination threshold, the capacity control unit sets the capacity of the swing motor at the time of the combined operation to the second capacity. When the tilt of the construction machine detected by the tilt detection unit is equal to or greater than the tilt threshold while performing control for adjustment, the capacity of the swivel motor at the time of the combined operation is set to the second capacity. Construction machinery that is configured to perform controls to adjust to smaller capacities. The construction machine according to any one of claims 1 to 5.
An inclination detection unit for detecting the inclination of the construction machine,
Further, a turning operation direction detecting unit for detecting the operating direction of the turning operation received by the turning operation member is provided.
The capacity control unit
When the inclination of the construction machine detected by the inclination detection unit is less than the inclination threshold value, or the inclination of the construction machine detected by the inclination detection unit and the rotation operation detected by the rotation operation direction detection unit. When the swivel direction of the upper swivel body obtained based on the operation direction of is not the swivel fall direction which is the direction including the component in the direction of gravity, the capacity of the swivel motor at the time of the combined operation is the capacity of the second capacity. While controlling to adjust to
The inclination of the construction machine detected by the inclination detection unit is equal to or higher than a preset inclination threshold, and the inclination of the construction machine detected by the inclination detection unit and the inclination of the construction machine are detected by the turning operation direction detection unit. When the swivel direction of the upper swivel body obtained based on the operation direction of the swivel operation is the swivel fall direction, the capacity of the swivel motor at the time of the combined operation is set to a capacity smaller than the second capacity. Construction machinery that is configured to give control to adjust. The construction machine according to any one of claims 1 to 7.
A differential pressure detection unit for detecting the differential pressure between the hydraulic oil supply oil passage and the hydraulic oil return oil passage connected to the swivel motor, and
A torque calculation unit that calculates a provisional turning torque based on the differential pressure detected by the differential pressure detection unit and the second capacitance is further provided.
When the provisional turning torque calculated by the torque calculation unit is less than a preset torque threshold value, the capacity control unit adjusts the capacity of the swing motor during the combined operation to the second capacity. When the provisional turning torque calculated by the torque calculation unit is equal to or greater than the torque threshold value, the capacity of the turning motor at the time of the combined operation is larger than the capacity of the second capacity. Construction machinery that is configured to perform controls to adjust to smaller capacities.

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