JP7223264B2 - construction machinery - Google Patents

Description

The present invention relates to a construction machine comprising a base, an upper revolving body mounted on the base so as to be able to turn, and an attachment mounted on the upper revolving body.

In general, a construction machine includes a base, an upper revolving structure mounted on the base so as to be able to turn, an attachment mounted on the upper revolving structure, a hydraulic pump for discharging hydraulic oil, and a A swing motor receives supply of the hydraulic oil discharged and operates to swing the upper swing structure, and a swing motor receives supply of the hydraulic oil discharged from the hydraulic pump and operates to operate the attachment. an actuator;

For example, Japanese Patent Laid-Open No. 2003-100000 discloses a system that uses a plurality of actuators including a swing motor and an arm cylinder, a plurality of hydraulic pumps, a plurality of control valves including both control valves for the swing motor and the arm cylinder, and oil from the plurality of hydraulic pumps. Hydraulic control provided with a switching valve that switches between a first position where oil is supplied separately to both control valves for swing motor and arm cylinder and a second position where oil is combined and supplied from a plurality of hydraulic pumps. circuit is disclosed. The hydraulic control circuit further includes a flow rate control valve as meter-in throttle means for throttle the amount of oil supplied to the arm cylinder when swinging and arm pulling operations are performed. When pressurized oil is supplied from a common pump to both the swing motor control valve and the arm cylinder control valve, the operating pressure required to drive the swing motor is relatively high. To solve the problem that when a combined operation is performed in which an arm operation for operating an arm cylinder requiring a relatively small operating pressure is performed at the same time, the turning operation is delayed with respect to the operation of the attachment. The hydraulic control circuit reduces the arm pulling speed by reducing the amount of oil supplied to the arm cylinder at the time of the compound operation, and eliminates the delay in the turning operation at the time of the compound operation in which the turning operation and the arm pulling operation are performed at the same time. It is something to do.

Japanese Patent Application Laid-Open No. 2001-295804

However, in the hydraulic control circuit disclosed in Patent Document 1, the meter-in throttle means reduces the amount of oil supplied to the arm cylinder during the compound operation, resulting in unnecessary pressure loss. That is, part of the work done by the hydraulic pump is released as heat energy due to the pressure loss.

SUMMARY OF THE INVENTION An object of the present invention is to suppress the occurrence of a delay in the swinging motion of the upper swing body while suppressing the occurrence of pressure loss during a combined operation in which a swinging operation and an attachment operation are performed at the same time. It is to provide the machine.

As means for solving the above-mentioned problems, the inventors of the present invention have found that the capacity of the swing motor, the motor differential pressure in the swing motor (the differential pressure between the hydraulic oil supply passage and the hydraulic oil return passage connected to the swing motor) ) and turning torque. The swing torque is proportional to the product of the displacement of the swing motor and the motor differential pressure. 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 art. do. On the other hand, out of the turning operation and the attachment operation, the motor differential pressure during the single turning operation in which only the turning operation is performed without performing the attachment operation is larger than the motor differential pressure during the combined operation. However, increasing the capacity of the swing motor during the single swing operation may cause excessive torque in which the swing torque is too large during the single swing operation. Based on these viewpoints, the present inventors adopted a variable displacement swing motor as the swing motor, and while adjusting the displacement of the swing motor to the first displacement during the single swing operation, The inventors have come up with capacity control for adjusting the capacity of the turning motor to a second capacity, which is larger than the first capacity, during a combined operation. This capacity control makes it possible to secure the turning torque, particularly the starting torque, during the compound operation even when the operating pressure of the actuator for the attachment is low, and furthermore, the above-mentioned Since the meter-in throttling means becomes unnecessary, it is possible to suppress the occurrence of pressure loss. In addition, since the first displacement of the swing motor during the single swing operation is smaller than the second displacement of the swing motor during the combined operation, the capacity control is performed in such a manner that the overdrive is performed during the single swing operation. Allows torque generation to be suppressed.

Each of the first to fourth inventions has been made from such a point of view. Each of the first to fourth inventions is a construction machine comprising a base, an upper revolving body mounted on the base so as to be able to turn, an attachment mounted on the upper revolving body, a hydraulic pump that discharges hydraulic oil; a variable displacement swing motor that receives supply of the hydraulic oil discharged from the hydraulic pump and operates to swing the upper swing body; and hydraulic oil that is discharged from the hydraulic pump An actuator that operates to operate at least a portion of the attachment upon receipt of the supply of the hydraulic oil, a turning operation member that receives a turning operation for turning the upper turning body, and operates at least a portion of the attachment. an attachment operation member that receives an attachment operation for causing the movement of the body, and a capacity control unit. The displacement control unit performs control for adjusting the displacement of the swing motor to a preset first displacement during a single swing operation in which the swing operation is performed but the attachment operation is not performed. and is configured to perform control for adjusting the displacement of the swing motor to a second displacement larger than the first displacement during a combined operation in which the swing operation and the attachment operation are performed simultaneously. there is

In this construction machine, the displacement of the swing motor during the combined operation is adjusted to the second displacement larger than the displacement of the swing motor during the single swing operation. This means that the turning torque for turning the upper turning body, especially the upper turning body, can be achieved without performing the conventional control for throttling the oil amount to the cylinder, which is accompanied by the generation of the pressure loss, or while limiting this control. To enable the starting torque to be secured to initiate the swing of the swing body. On the other hand, during the single swing operation, the displacement of the swing motor is adjusted to the first displacement, so the generation of the excessive torque is suppressed.

The construction machine further includes a swing speed detector for detecting a swing speed of the upper swing structure, and the capacity controller controls the swing speed detected by the swing speed detector as a preset speed threshold value. When it is less than the speed threshold value, control is performed to adjust the displacement of the swing motor to the second displacement during the combined operation, and the swing speed detected by the swing speed detection unit is equal to the speed threshold value. In the case above, it is preferable that control is performed to adjust the displacement of the turning motor to be smaller than the second displacement during the combined operation.

In this aspect, when the turning speed is less than the speed threshold, that is, when there is a strong need to increase the starting torque during the combined operation, the capacity of the turning motor is increased to secure the starting torque. make it possible to On the other hand, in this aspect, when the turning speed is equal to or higher than the speed threshold during the combined operation, that is, when there is little need to increase the turning torque even during the combined operation, the turning motor is turned on. Control for adjusting the displacement to the second displacement is not performed, and control for adjusting the displacement of the swing motor to be smaller than the second displacement is performed. This makes it possible to reduce the degree of reduction in maximum swing speed due to the increased capacity of the swing motor. In this aspect, the capacity smaller than the second capacity may be the first capacity, or may be a capacity different from the first capacity. Further, in this aspect, the speed threshold is set to a value that enables determination of whether or not the turning state of the upper turning body is in the initial stage of turning. The initial stage includes a start-up of swing when the upper swing body starts swinging from a stopped state, and a low swing speed after the upper swing body has started swinging.

The construction machine according to the first invention further includes a discharge pressure detection section for detecting the discharge pressure of the hydraulic pump, and the displacement control section presets the discharge pressure detected by the discharge pressure detection section. If the discharge pressure is less than the set discharge pressure threshold value, control is performed to adjust the displacement of the swing motor during the combined operation to the second displacement, while the discharge pressure detected by the discharge pressure detection unit is controlled. When the pressure is equal to or higher than the discharge pressure threshold value, control is performed to adjust the displacement of the swing motor during the combined operation to be smaller than the second displacement .

In this aspect, when the discharge pressure is less than the discharge pressure threshold value, that is, when there is a strong need to increase the swing torque (especially the starting torque) during the combined operation, the displacement of the swing motor is increased. 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 ensured even during the combined operation, the turning motor is turned on. Control for adjusting the displacement to the second displacement is not performed, and control for adjusting the displacement of the swing motor to be smaller than the second displacement is performed. This makes it possible to reduce the degree of reduction in maximum swing speed due to the increased capacity of the swing motor. In this aspect, the capacity smaller than the second capacity may be the first capacity, or may be a capacity different from the first capacity. Further, in this aspect, the discharge pressure threshold is a discharge pressure that enables a smooth turning motion even when the displacement of the turning motor is smaller than the second displacement. is set to a value that can determine

In the construction machine, the attachment includes a boom that is supported by the upper rotating body so that it can be raised and lowered, an arm that is rotatably connected to the tip of the boom, and a tip attachment that is linked to the tip of the arm. , wherein 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, during a combined operation of the turning operation and the arm operation for operating the arm, even if the operating pressure of the arm is low, the occurrence of the pressure loss as in the conventional case is suppressed. while enabling the turning torque (especially the starting torque) to be ensured.

In the construction machine, the attachment includes a boom that is supported by the upper rotating body so that it can be raised and lowered, an arm that is rotatably connected to the tip of the boom, and at least one that is connected to the tip of the arm. a tip attachment, wherein the actuator is an actuator operable to operate the tip attachment, and the attachment operation may be an operation for operating the tip attachment.

In this aspect, at the time of the combined operation of the turning operation and the tip attachment operation for operating the tip attachment, even if the working pressure of the tip attachment is low, the conventional pressure loss does not occur. It enables the turning torque (particularly the starting torque) to be secured while allowing it to be suppressed.

A construction machine according to a second aspect of the invention further includes a tilt detection section for detecting a tilt of the construction machine, and the capacity control section is configured such that the tilt of the construction machine detected by the tilt detection section is preset. If the inclination is less than the inclination threshold, control is performed to adjust the displacement of the swing motor during the combined operation to the second displacement, while the inclination of the construction machine detected by the inclination detection unit is controlled. is greater than or equal to the tilt threshold value, control is performed to adjust the capacity of the turning motor to be smaller than the second capacity at the time of the compound operation.

If the inclination of the construction machine is equal to or greater than the inclination threshold, cavitation may occur on the suction side of the swing motor. Therefore, in this aspect, when there is a possibility that cavitation may occur, that is, when the construction machine is placed on a slope with a predetermined inclination or more, the rotation of the swing motor is uniformly performed even during the combined operation. Control for adjusting the displacement to the second displacement is not performed, and control for adjusting the displacement of the swing motor to be smaller than the second displacement is performed. This makes it possible to suppress the occurrence of cavitation due to tilting of the construction machine. In this aspect, the capacity smaller than the second capacity may be the first capacity, or may be a capacity different from the first capacity.

A construction machine according to a third aspect of the invention includes a tilt detection section for detecting a tilt of the construction machine, and a turning operation direction detection section for detecting an operation direction of the turning operation received by the turning operation member. Further, the capacity control unit controls the tilt of the construction machine detected by the tilt detection unit when the tilt of the construction machine is less than a preset tilt threshold, or the tilt of the construction machine detected by the tilt detection unit and the If the turning direction of the upper turning body obtained based on the operation direction of the turning operation detected by the turning operation direction detection unit is not the turning and dropping direction that is the direction including the component of the direction of gravity, during the combined operation while performing control for adjusting the capacity of the swing motor to the second capacity, the inclination of the construction machine detected by the inclination detection unit is equal to or greater than the inclination threshold value, and the inclination detection unit When the turning direction of the upper turning body obtained based on the inclination of the construction machine detected by the turning operation direction detection unit and the operation direction of the turning operation detected by the turning operation direction detection unit is the turning falling direction, It is configured to perform control for adjusting the capacity of the turning motor to be smaller than the second capacity during a compound operation .

In this aspect, when the tilt of the construction machine is less than the tilt threshold value or when the upper swing body is not swinging in the swing drop direction, cavitation is less likely to occur in the swing motor. Control is performed to adjust the displacement of the swing motor to the second displacement during the compound operation. In particular, when the upper swing structure swings in a direction opposite to the swing-down direction, that is, in a direction against gravity during the compound operation, the swing torque (particularly the starting torque) is reduced during the compound operation. need to be enlarged. In this case, the turning torque (especially the starting torque) of the upper turning body can be ensured by performing control for adjusting the capacity of the turning motor to the second capacity. to On the other hand, when the inclination of the construction machine is equal to or greater than the inclination threshold and the upper rotating body is rotating in the rotating drop direction, even during the combined operation, the capacity of the rotating motor is set to the above-mentioned value. Control for adjusting the displacement to the second displacement is not performed, and control for adjusting the displacement of the swing motor to a displacement smaller than the second displacement is performed. This makes it possible to suppress the occurrence of cavitation in the swing motor. In this aspect, the capacity smaller than the second capacity may be the first capacity, or may be a capacity different from the first capacity.

A construction machine according to a fourth aspect of the present invention includes a differential pressure detection unit for detecting a differential pressure between a hydraulic oil supply passage and a hydraulic oil return passage connected to the swing motor, and the differential pressure detection unit. and a torque calculation unit that calculates a provisional turning torque based on the differential pressure and the second capacity, wherein the capacity control unit calculates the provisional turning torque calculated by the torque calculation unit in advance. If it is less than the set torque threshold, control is performed to adjust the displacement of the swing motor during the combined operation to the second displacement, while the provisional swing calculated by the torque calculation unit is performed. When the torque is equal to or greater than the torque threshold, control is performed to adjust the capacity of the swing motor during the combined operation to a capacity smaller than the second capacity .

In this aspect, when the provisional swing torque is equal to or greater than the torque threshold value, control for adjusting the displacement of the swing motor to the second displacement is not performed even during the combined operation, and the swing is performed. 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 aspect, the capacity smaller than the second capacity may be the first capacity, or may be 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 revolving motion of the upper revolving body and the motion of the attachment are simultaneously performed by hydraulic oil discharged from a common hydraulic pump. A construction machine is provided that can suppress the occurrence of a delay in the swinging motion of the upper swing body while keeping the upper swing body from being delayed.

1 is a side view showing a construction machine according to an embodiment of the invention; FIG. FIG. 4 is a schematic diagram showing a grapple, which is an example of a tip attachment attached to the tip of the arm of the construction machine. FIG. 4 is a schematic diagram showing a crusher, which is an example of a tip attachment attached to the tip of the arm of the construction machine. FIG. 4 is a schematic diagram showing a breaker, which is an example of a tip attachment attached to the tip of the arm of the construction machine. FIG. 4 is a schematic diagram showing a fork, which is an example of a 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. 3 is a block diagram showing the functional configuration of a control device in the construction machine and its input/output signals; FIG. It is a flow chart which shows the arithmetic control action of the said control apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION 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 invention. As shown in FIG. 1, the construction machine 100 includes a crawler-type lower traveling body 1 that constitutes a base body, and a lower traveling body 1 that can turn around a turning center axis Z perpendicular to the traveling surface of the lower traveling body 1. and an attachment 3 mounted on the upper revolving body 2.

The attachment 3 includes a boom 4 supported by the upper rotating body 2 so as to be able to rise and fall, an arm 5 rotatably connected to the tip of the boom 4, and a plurality of tip attachments. The plurality of tip attachments includes tip attachment 6 (bucket 6) shown in FIG. 1 and tip attachments 6A to 6D shown in FIGS. Any one of the plurality of tip attachments is selectively detachably connected to the tip of the arm 5 .

The tip attachment 6A shown in FIG. 2 is a grapple 6A for gripping and conveying 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. Prepare.

A tip attachment 6B shown in FIG. 3 is a crusher 6B for dismantling a concrete structure, for example. 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 in, for example, rock excavation, rock splitting, and concrete crushing. The breaker 6C includes a bracket 61C attached to the tip of the arm 5, a breaker body 62C supported by the bracket 61C, and a chisel 63C supported by the breaker body 62C and reciprocating in the axial direction thereof.

A 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. As shown in FIG. FIG. 7 is a block diagram showing the functional configuration and input/output signals of the control device 70 in the construction machine 100. As shown in FIG. 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 swing motor 30, and a plurality of actuators. , a swing control valve 41 , a plurality of attachment control valves, a swing operation device 81 , a plurality of attachment operation devices, a plurality of detectors, and a control device 70 . The plurality of attachment control valves include an arm control valve 42, an option control valve 43, an unillustrated boom control valve, and an unillustrated tip attachment control valve. The plurality of attachment operating devices include an arm operating device 82, an option 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 whose pump displacement is adjustable. Each of these hydraulic pumps 21 and 22 has a regulator (not shown), and upon receiving an input of a displacement command signal from the control device 70, the regulator adjusts the pump displacement to a displacement corresponding to the displacement command signal. 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 hydraulic oil in a tank (not shown).

The swing motor 30 is a hydraulic motor for driving the upper swing body 2 to swing. The swing motor 30 has an output shaft (not shown) that rotates by receiving supply of hydraulic oil discharged from the first hydraulic pump 21. The output shaft rotates the upper swing body 2 in both left and right directions. is connected to the upper revolving body 2. Specifically, the turning motor 30 has a first port 30a and a second port 30b, and when hydraulic oil is supplied to one of these ports, the turning motor 30 rotates in the direction corresponding to the one port. As the output shaft rotates, hydraulic oil is discharged from the other port. The swing motor 30 is a variable capacity hydraulic motor whose motor capacity is adjustable. The swing motor 30 has a regulator (not shown), and the regulator receives an input of a displacement command signal from the control device 70 to adjust the motor displacement to a displacement corresponding to the displacement command signal.

The plurality of actuators, as shown in FIG. an arm cylinder 8 that operates to rotate the tip attachment (the bucket 6 in FIG. 1) with respect to the arm 5; and an option cylinder 10 (see FIG. 6). ,including.

As shown in FIG. 6, each of the arm cylinder 8 and the option cylinder 10 operates by being supplied with hydraulic oil discharged from the same hydraulic pump as the first hydraulic pump 21 that drives the swing motor 30 to swing. is configured to That is, the swing motor 30, the arm cylinder 8, and the option cylinder 10 are connected to a common first hydraulic pump 21. As shown in FIG. 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 being supplied with hydraulic oil discharged from the second hydraulic pump 22. It is

The arm cylinder 8 has a bottom chamber 8a and a rod chamber 8b on the opposite side. The arm cylinder 8 expands when hydraulic oil is supplied to the bottom chamber 8a, moves the arm 5 in one direction, discharges the hydraulic oil from the rod chamber 8b, and conversely flows into the rod chamber 8b. When hydraulic fluid is supplied, it contracts to move the arm 5 in the other direction and discharge the hydraulic fluid 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. is a cylinder of

The option cylinder 10 has a bottom chamber 10a and a rod chamber 10b on the opposite side. The optional cylinder 10 expands when hydraulic oil is supplied to the bottom chamber 10a to move a portion of the tip attachment in one direction, discharge hydraulic oil from the rod chamber 10b, and conversely discharge the rod chamber 10b. When hydraulic fluid is supplied to 10b, it contracts to move the part of the tip attachment in the other direction and discharge the hydraulic fluid 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, for example, on the grapple main body 62A and operates 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, for example, in the crusher main body 62B and operates 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, for example, on the breaker body 62C, and is adapted to cause the chisel 63C to advance and retreat (reciprocate) in the axial direction with respect to the breaker body 62C. to operate. When the tip attachment is the fork 6D shown in FIG. 5, the option cylinder 10 is provided on the fork body 62D, for example, and operates to open and close the pair of opening and closing arms 63D. Note that the bucket 6 is not provided with the optional cylinder 10 as described above.

The operating pressure required when each of the tip attachments 6A to 6D performs the specific operation, that is, the operating pressure required to operate the option cylinder 10 differs depending on the type of tip attachment. . Among the tip attachments 6A to 6D, the grapple 6A and the fork 6D generally have low operating pressures, and the crusher 6B and the breaker 6C generally have high operating pressures.

As shown in FIG. 6 , the swing control valve 41 is interposed between the first hydraulic pump 21 and the swing motor 30 . The swing control valve 41 selectively guides hydraulic oil for driving the swing motor 30 from the first hydraulic pump 21 to either of the first and second ports 30a and 30b of the swing motor 30. In addition, it controls the swing flow rate, which is the flow rate of hydraulic oil supplied to the swing motor 30 . The swivel control valve 41 is a three-position pilot switching valve, and has a pair of swivel pilot ports (one swivel pilot port P1 and an unillustrated swivel pilot port on the opposite side).

The swing control valve 41 is kept at a neutral position when the pilot pressures supplied to the pair of swing pilot ports are both 0 or very small, and the pressure between the first hydraulic pump 21 and the swing motor 30 is maintained. and connect the center line L1 to the tank. When a pilot pressure above a certain level is supplied to either one of the pair of swing pilot ports, the swing control valve 41 is neutralized in a direction corresponding to the swing pilot port with a stroke corresponding to the magnitude of the pilot pressure. position, connecting the turning supply line L11 branching from the center line L1 to the first port 30a or the second port 30b, and narrowing the center line L1 to a degree corresponding to the stroke, thereby The turning motor 30 is operated at a direction and speed corresponding to the stroke.

The swing control valve 41 and the first port 30a of the swing motor 30 are connected by a first port line L41, and the swing control valve 41 and the second port 30b of the swing motor 30 are connected to the second port. It is connected by a port line L42. By shifting the swing control valve 41 from the neutral position, one of the first port line L41 and the second port line L42 functions as a hydraulic oil supply passage, and the other line functions as a hydraulic oil supply passage. It 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 fluid 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 hydraulic oil supplied to the arm cylinder 8, is controlled. The arm control valve 42 is a three-position pilot switching valve, and has a pair of arm pilot ports (one arm pilot port P2 and an unillustrated arm pilot port on the opposite side).

The arm control valve 42 is kept at a neutral position when the pilot pressures supplied to the pair of arm pilot ports are both 0 or very small, and the pressure between the first hydraulic pump 21 and the arm cylinder 8 is maintained. is cut off and the center line L2 is connected to the tank. The arm control valve 42 shifts from the neutral position with a stroke corresponding to the magnitude of the pilot pressure when a pilot pressure above a certain level is supplied to one of the pair of arm pilot ports, and shifts 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 narrowed to a degree corresponding to the stroke, thereby moving the arm cylinder 8 in the direction corresponding to the stroke. 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 three-position pilot switching valve, and has a pair of option pilot ports (one option pilot port P3 and the opposite option pilot port (not shown)).

The option control valve 43 is kept at a neutral position when the pilot pressures supplied to the pair of option pilot ports are both 0 or very small, and the pressure between the first hydraulic pump 21 and the option cylinder 10 is maintained. is cut off and the center line L3 is connected to the tank. The option control valve 43 shifts from the neutral position with a stroke corresponding to the magnitude of the pilot pressure when a pilot pressure above a certain level is supplied to one of the pair of option pilot ports, and shifts from the center line L3. The branched option supply line L31 is connected to the bottom chamber 10a or the rod chamber 10b, and the center line L3 is narrowed to a degree corresponding to the stroke, thereby moving the option cylinder 10 in a direction corresponding to the stroke. operate at speed.

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

The swing operation device 81 receives a swing operation for moving the swing motor 30 , and the pilot pressure corresponding to the swing operation is supplied from the pilot pump 23 to one of the pair of swing pilot ports of the swing control valve 41 . Acts to allow it to be supplied alternatively. Specifically, the turning operation device 81 is provided between a turning operation lever 81a, which is a turning operation member that can be turned by receiving the turning operation, and the pilot pump 23 and the pair of turning pilot ports. and an intervening swivel pilot valve 81b. The swivel pilot valve 81b is closed to block communication between the pilot pump 23 and the pair of swivel pilot ports when the swivel operation lever 81a is not operated and is in the neutral position. is rotated from the neutral position, a pilot pressure corresponding to the amount of rotation is supplied to the turning pilot port corresponding to the direction of the turning operation among the pair of turning pilot ports. Open the valve so that

The arm operating device 82 receives an arm operation (an example of an attachment operation in the present invention) for moving the arm cylinder 8 , and the pilot pressure corresponding to the arm operation is transferred from the pilot pump 23 to the arm control valve 42 to the above-mentioned It operates to allow alternative supply to either of a 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. and an arm pilot valve 82b interposed between the pair of arm pilot ports. The arm pilot valve 82b is closed to block communication between the pilot pump 23 and the pair of arm pilot ports when the arm control lever 82a is not operated and is in the neutral position. is rotated from the neutral position, a pilot pressure corresponding to the amount of the rotation is supplied to the arm pilot port corresponding to the direction of the rotation of the pair of arm pilot ports. Open the valve so that

The option operation device 83 receives an option operation (an example of an attachment operation in the present invention) for moving the option cylinder 10 , and the pilot pressure corresponding to the option operation is supplied from the pilot pump 23 to the option control valve 43 . It operates to allow alternative supply to either of a 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) that can be rotated in response to the option operation, and the pilot pump 23. and an option pilot valve 83b interposed between the pair of option pilot ports. The option pilot valve 83b is closed to block communication between the pilot pump 23 and the pair of option pilot ports when the option control lever 83a is not operated and is in the neutral position. is rotated from the neutral position, a pilot pressure corresponding to the amount of rotation is supplied to the option pilot port corresponding to the direction of the rotation operation among the pair of option pilot ports. Open the valve so that Note that the turning operation device 81, the arm operation device 82, and the option operation device 83 may have pedal-type operation members (operation pedals).

As shown in FIG. 7, the plurality of detection units include a turning speed detection unit 90, a discharge pressure detection unit 91, an inclination detection unit 92, a differential pressure detection unit 93, a turning operation direction detection unit 94, an arm An operation direction detection unit 95 and an optional operation direction detection unit 96 are provided. Electrical signals corresponding to the detection values detected by the plurality of detection units are input to the control device 70 .

The turning speed detection unit 90 is a sensor for detecting the rotational speed of the turning motor 30 as the turning speed. The turning speed detection unit 90 detects the turning speed, converts it into a turning detection signal that 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, turning direction, etc. 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 detection unit 90, a turning speed sensor such as a gyro sensor, an encoder, or a resolver can be used, but it is not limited to these.

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

During a combined operation in which a turning operation for operating the turning motor 30 and an arm pulling operation for extending the arm cylinder 8 are performed simultaneously, the discharge pressure detecting section 91 requires a relatively small operating pressure to drive. A discharge pressure that is approximately the same as the working pressure for extending the arm cylinder 8 is detected.

During a combined operation in which a turning operation for operating the turning motor 30 and an optional operation for extending the option cylinder 10 are performed at the same time, the discharge pressure detection unit 91 detects the working pressure required to operate the turning motor 30 and the A discharge pressure that is approximately equal to one of the operating pressures required to extend the option cylinder 10 is detected. When the operating pressure required to extend the option cylinder 10 is greater than the operating pressure required to operate the swing motor 30, the discharge pressure detector 91 detects A discharge pressure is detected 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 section 91 detects the pressure required to extend the option cylinder 10. A discharge pressure is detected that is approximately equal to the required operating pressure.

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

The discharge pressure detector 91 is provided, for example, in a 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 detection unit 91 is provided may be any position where the discharge pressure of the hydraulic pump 21 can be detected, and is not limited to the pump line L0, and may be the line L1 or the line L2.

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

The differential pressure detection unit 93 is a pressure sensor that detects differential pressure (effective differential pressure) in the swing motor 30 . Specifically, the differential pressure detector 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 fluid at the first port 30a of the swing motor 30, and outputs an electrical signal corresponding to the first port pressure. is a pressure sensor that produces a first port pressure sensing signal that is The second port pressure sensor 93b detects a second port pressure (MB), which is the pressure of hydraulic fluid at the second port 30b of the swing motor 30, and outputs an electric signal corresponding to the second port pressure. is a pressure sensor that produces a second port pressure sensing signal that is These port pressure detection signals are input to the control device 70 . The first port pressure sensor 93a is provided, for example, on the first port line L41, and the second port pressure sensor 93b is provided, for example, on 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). One of the pair of swing pilot pressure sensors, the swing pilot pressure sensor 94a, detects the swing pilot pressure of hydraulic fluid supplied from the swing remote control valve 81b to one of the swing pilot ports P1 of the swing control valve 41. , is converted into a turning pilot pressure detection signal, which is an electrical signal, and the detection signal is input to the control device 70 . Of the pair of swing pilot pressure sensors, the other swing pilot pressure sensor (not shown) is a swing pilot of hydraulic oil supplied from the swing remote control valve 81 b to the other swing pilot port (not shown) of the swing control valve 41 . The pressure is detected, 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 operating direction detection unit 95 is composed of a pair of arm pilot pressure sensors (a pair of pressure sensors). One arm pilot pressure sensor 95a of the pair of arm pilot pressure sensors detects the arm pilot pressure of hydraulic fluid supplied from the arm remote control valve 82b to one arm pilot port P2 of the arm control valve 42. , is converted into an arm pilot pressure detection signal, which is an electrical 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 (not shown) is an arm pilot pressure sensor of hydraulic oil supplied from the arm remote control valve 82b to the other arm pilot port (not shown) of the arm control valve 42. The pressure is detected, converted into an arm pilot pressure detection signal, which is an electrical signal, and the detection signal is input to the control device 70 .

The option operation direction detection unit 96 is composed of a pair of option pilot pressure sensors (a pair of pressure sensors). Of the pair of option pilot pressure sensors, one option pilot pressure sensor 96a detects the option pilot pressure of hydraulic fluid supplied from the option remote control valve 83b to one option pilot port P3 of the option control valve 43. , is converted into an option pilot pressure detection signal, which is an electrical signal, and the detection signal is input to the control device 70 . Of the pair of option pilot pressure sensors, the other option pilot pressure sensor (not shown) is an option pilot of hydraulic oil supplied from the option remote control valve 83b to the other option pilot port (not shown) of the option control valve 43. pressure is detected, this is converted into an option 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 detection section 97 , which detects the discharge pressure of the second hydraulic pump 22 to detect the discharge pressure of the second hydraulic pump 22 . is a pressure sensor for detecting an operating pressure (operating pressure of another actuator included in the construction machine 100) that is equivalent to the discharge pressure of the hydraulic pump 22 of the construction machine 100. As shown in FIG. The other actuators include, for example, the boom cylinder 7, but are not limited thereto.

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 for the CPU, and the like. consists of

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

The displacement control unit 71 performs control for adjusting the displacement of the swing motor 30 to a preset first displacement during a single swing operation in which the swing operation is performed but the attachment operation is not performed. During a combined operation in which the turning operation and the attachment operation are performed simultaneously, in principle, control is performed to adjust the capacity of the turning motor 30 to a second capacity larger than the first capacity. configured to do so. The details of the function of the capacity control unit 71 will be described later.

The torque calculation section 72 calculates a provisional turning torque based on the differential pressure detected by the differential pressure detection section 93 and the second capacity. The provisional turning torque is set for the purpose of preventing excessive torque from occurring before the capacity control unit 71 changes the capacity of the turning motor 30 from the first capacity to the second capacity. A swing torque is provisionally calculated based on the differential pressure in the swing motor 30 and the second capacity. The torque calculator 72 calculates the provisional turning torque based on, for example, the following equation (1).

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

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

The operation determination unit 75 determines whether or not the single turning operation has been performed. Further, the operation determination unit 75 determines whether or not the compound operation has been performed. Specifically, the operation determination unit 73 determines whether or not the turning operation has been performed based on the turning pilot pressure detection signal detected by the turning operation direction detection unit 94, and determines whether or not the turning operation has been performed. Based on the arm pilot pressure detection signal detected by 95, it is determined whether the arm operation has been performed, and based on the option pilot pressure detection signal detected by the option operation direction detection unit 96, the option operation is detected. is performed. When the operation determination unit 75 determines that the turning operation has been performed and that neither the arm operation nor the option operation has been performed, it determines that the single turning operation has been performed. do. When determining that the turning operation has been performed and at least one of the arm operation and the option operation has been performed, the operation determination unit 75 determines that the combined operation has been performed.

The turning brake determination unit 76 determines whether or not the turning of the upper turning body 2 is not braked. Specifically, 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 at the neutral position, the turning brake determination unit 76 It can be determined that the swinging of the upper swing body 2 is braked. Further, the turning brake determination unit 76 determines whether the turning of the upper turning body 2 is braked based on the differential pressure in the turning motor 30 detected by the differential pressure detecting unit 93, for example. Alternatively, it can be determined whether the upper swing body 2 is accelerating.

The tilt determination unit 77 determines whether the tilt of the upper swing body 2 (tilt of the vehicle body) of the construction machine 100 is less than a preset tilt threshold value D based on the detection signal detected by the tilt detection unit 92. determine whether Further, the tilt determination unit 77 determines whether the turning direction of the upper turning body 2 is the turning and dropping 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. Make a judgment that there is no

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

FIG. 8 is a flow chart showing the arithmetic 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 thereto (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), control for adjusting the displacement of the swing motor to the second displacement is unnecessary. Control is performed to adjust (maintain) the displacement of the turning motor 30 to the first displacement (step S10). Specifically, when the turning motor 30 is, for example, a swash plate type hydraulic motor, the swash plate is set at, for example, a small tilt position corresponding to the first displacement.

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

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 ( step S3). When the swing pilot pressure is less than a preset swing pilot pressure threshold value B (NO in step S3), the operation determination unit 75 determines that the swing operation is not performed. In this case, since the compound operation is not performed, the displacement control section 71 performs control for adjusting (maintaining) the displacement of the swing motor to the first displacement (step S10).

When the swing pilot pressure is equal to or higher than the swing pilot pressure threshold value B (YES in step S3), the operation determination unit 75 determines that the swing operation has been performed. In such a case, the torque calculation unit 72 calculates provisional turning torque based on the differential pressure detected by the differential pressure detection unit 93 and the second capacity, 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 a preset torque threshold value C (step S4). When the provisional turning torque is equal to or greater than the torque threshold value C (NO in step S4), the capacity control unit 71 reduces the capacity of the turning motor to the first capacity in order to prevent excessive torque from occurring. Control for adjusting (maintaining) is performed (step S10).

When the provisional turning torque is less than the torque threshold value C (YES in step S4), the turning brake determination unit 76 determines whether the turning of the upper turning body 2 is not braked. is determined (step S5). When the swing of the upper swing body 2 is braked (NO in step S5), that is, when the swing is decelerating, the displacement of the swing motor is adjusted to the second displacement. Therefore, the displacement control section 71 performs control for adjusting (maintaining) the displacement of the turning motor 30 to the first displacement (step S10).

When the upper rotating body 2 is not braked for turning (YES in step S5), that is, when the turning is not decelerating, the inclination determining section 77 makes the following determinations. That is, the tilt determination unit 77 determines whether the tilt of the upper swing body 2 (tilt of the vehicle body) is less than a preset tilt threshold value D based on the detection signal detected by the tilt detection unit 92 . Determine (step S6). Further, the tilt determination unit 77 determines whether the turning direction of the upper turning body 2 is the turning and dropping 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 (step S6). Here, the fact that the turning direction is not the turning-down direction means that the turning direction is the horizontal direction, and that the turning direction is the direction opposite to the turning-down direction (that is, the climbing direction). including. When the tilt of the upper swing structure 2 is equal to or greater than the tilt threshold value D and the swing direction of the upper swing structure 2 is the swing drop direction (NO in step S6), the swing motor 30 is prevented from generating cavitation. In order to prevent this, the capacity control unit 71 performs control to adjust (maintain) the capacity of the turning motor 30 to the first capacity (step S10).

When the tilt of the upper swing structure 2 is less than the tilt threshold value D, or when the swing direction of the upper swing structure 2 is not the swing drop direction (YES in step S6), the swing speed determination unit 78 determines the Based on the detection signal detected by the turning speed detector 90, it is determined whether or not the turning speed is less than a preset speed threshold value E (step S7). When the turning speed is equal to or greater than the speed threshold E (NO in step S7), control for adjusting the displacement of the turning motor to the second displacement is unnecessary. Control is performed to adjust (maintain) the displacement of the swing motor 30 to the first displacement (step S10).

It should be noted that the determination of YES in step S6 means that the inclination of the upper revolving structure 2 is less than the inclination threshold value D, and that the revolving direction of the upper revolving structure 2 is not the revolving falling direction. It is 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 determines whether the arm operation and the option operation are performed based on the arm pilot pressure detection signal and the option pilot pressure detection signal. is 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 this case, since the compound operation is not performed, the displacement control section 71 performs control for adjusting (maintaining) the displacement of the swing motor to the first displacement (step S10).

When the arm pilot pressure is equal to or higher than the arm pilot pressure threshold value F, or when the option pilot pressure is equal to or higher than the option pilot pressure threshold value G (YES in step S8), the operation determination unit 75 performs the turning operation. and at least one of the arm operation and the option operation are performed simultaneously. In such a case, the displacement control section 71 performs control for adjusting the displacement of the swing motor 30 to the second displacement larger than the first displacement (step S9). Specifically, when the swing motor 30 is, for example, a swash plate type hydraulic motor, the swash plate is set, for example, at the large tilt position corresponding to the second displacement. After that, the control device 70 repeats the above steps S1 to S10.

It should be noted that the case where the determination in step S8 is YES means the condition that the arm pilot pressure is equal to or higher than the arm pilot pressure threshold value F, and the condition that the option pilot pressure is equal to or higher than the option pilot pressure threshold value G. at least one of the conditions is satisfied.

As described above, in the construction machine 100 according to the embodiment, the displacement of the swing motor 30 during the combined operation is adjusted to the second displacement larger than the displacement of the swing motor 30 during the single swing operation. be. This means that the turning torque for turning the upper turning body 2, especially the It is possible to secure the starting torque for starting the swing of the upper swing body 2. - 特許庁As a result, the output of the first hydraulic pump 21 can be efficiently transmitted to the swing motor 30, the arm cylinder 8 and the option cylinder 10 by suppressing unnecessary pressure loss. On the other hand, during the single swing operation, the displacement of the swing motor is adjusted to the first displacement, so the generation of the excessive torque is suppressed.

Further, in the construction machine 100 according to the embodiment, when the swing speed is less than the speed threshold, that is, when there is a strong need to increase the starting torque during the compound operation, the capacity of the swing motor 30 is reduced. is increased to ensure the starting torque. On the other hand, when the swing speed is equal to or higher than the speed threshold during the compound operation, that is, when there is little need to increase the swing torque even during the compound operation, the capacity of the swing motor 30 is reduced to the above value. Control is performed to adjust to the first capacity. This suppresses the decrease in the maximum swing speed caused by the adjustment of the displacement of the swing motor 30 to the second displacement, and the maximum swing speed equivalent to the maximum swing speed during the single swing operation is suppressed. 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, that is, when there is a high need to increase the turning torque (especially the starting torque) during the combined operation, It is possible to secure the turning torque by increasing the capacity of the turning motor 30. - 特許庁On the other hand, when the discharge pressure is equal to or higher than the discharge pressure threshold value during the compound operation, that is, when the swing torque is secured even during the compound operation, the displacement of the swing motor 30 is reduced to the above value. Control is performed to adjust to the first capacity. This suppresses a decrease in the maximum turning speed due to the adjustment of the capacity of the turning motor to the second capacity, and ensures a maximum turning speed equivalent to the maximum turning speed during the single turning operation. make it possible to

In the construction machine 100 according to the embodiment, even when the operating pressure of the arm is low during a combined operation of the turning operation and the arm operation for operating the arm, the pressure loss is reduced as in the conventional case. It is possible to secure the turning torque (particularly the starting torque) while suppressing the generation.

In the construction machine 100 according to the embodiment, during a combined operation of the turning operation and the tip attachment operation for operating the tip attachment, even if the operating pressure of the tip attachment is low, the conventional It is possible to ensure the turning torque (especially starting torque) while suppressing the occurrence of the pressure loss.

In the construction machine 100 according to the embodiment, when the tilt of the upper swing body 2 of the construction machine 100 is less than the tilt threshold or when the upper swing body 2 is not swinging in the swing drop direction, the Since the possibility of cavitation occurring in the swing motor 30 is low, control is performed to adjust the displacement of the swing motor 30 to the second displacement during the compound operation. In particular, when the upper swing body 2 swings in a direction opposite to the swing-dropping direction, that is, in a direction against gravity during the compound operation, the swing torque (especially the starting torque) is reduced during the compound operation. there is a strong need to increase In such a case, the construction machine 100 according to the embodiment is controlled to adjust the displacement of the swing motor 30 to the second displacement so that the swing torque (especially the starting torque) of the upper swing body 2 is reduced. ) is ensured. On the other hand, when the tilt of the upper swing body 2 of the construction machine 100 is equal to or greater than the tilt threshold and the upper swing body 2 is swinging in the swing drop direction, even during the combined operation, Control is performed to adjust the displacement of the turning motor 30 to the first displacement. This enables the occurrence of cavitation in the turning motor 30 to be suppressed.

In the construction machine 100 according to the embodiment, when the provisional swing torque is equal to or greater than the torque threshold, control is performed to adjust the displacement of the swing motor 30 to the first displacement even during the compound operation. 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 Displacement In the above embodiment, if NO in each of steps S2 to S8, control is performed to adjust the displacement of the swing motor 30 to the first displacement, but the present invention is not limited to this. That is, if NO in each of steps S2 to S8, control is performed to adjust the displacement of the swing motor 30 to a displacement smaller than the second displacement and different from the first displacement. may be broken.

B) Turning Speed Detector and Turning Speed Determining Unit In the above embodiment, the construction machine 100 includes a turning speed detecting unit and a turning speed determining unit, but these can be omitted.

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

D) Tilt Detection Section and Tilt Determination Section In the construction machine 100 according to the above embodiment, when there is a risk of cavitation occurring, that is, when the construction machine 100 is placed on a slope with a predetermined inclination or more, Even during the compound operation, control for adjusting the displacement of the swing motor 30 to the second displacement is not performed, and the displacement of the swing motor 30 is set to be smaller than the second displacement. Regulating controls may be implemented. This makes it possible to suppress the occurrence of cavitation due to the inclination of the upper swing body 2 of the construction machine 100 .

In the above embodiment, the construction machine 100 includes the tilt detector and the tilt determiner, but these can be omitted.

E) Regarding Differential Pressure Detector and Torque Calculator In the above embodiment, the construction machine 100 was provided with a differential pressure detector and a torque calculator, but these can be omitted.

F) Common Hydraulic Pump The first hydraulic pump 21 according to the above embodiment is also used to drive the swing 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 swing motor 30 and, for example, the boom cylinder 7, and also for driving the tip attachment cylinder 9. may be

G) Substrate In the above-described embodiment, the lower traveling structure 1 is used as the substrate, but the substrate is not limited to a structure that can travel like the lower traveling structure 1. 2 may be a base for supporting the device.

H) Tip Attachment In the above embodiment, a grapple, a crusher, a breaker and a fork were exemplified as replaceable tip attachments, but they are not limited to these.

I) Flowchart In the flow chart showing the arithmetic control operation of the control device 70 shown in FIG. 8, various signals are read (step S1), whether or not there is a swing operation (step S3), and whether or not arm operation and optional operation are performed (step S8). , changing the capacity of the swing motor 30 to the second capacity (step S9), and maintaining the capacity of the swing motor 30 at the first capacity (step S10) are essential, but steps other than the above must necessarily be included. no. Steps other than those described above can be incorporated into the arithmetic control operation as required.

1 Undercarriage (an example of a substrate)
2 Upper slewing body 3 Attachment 4 Boom 5 Arm 6 Bucket (an example of tip attachment)
6A grapple (example of tip attachment)
6B crusher (example of tip attachment)
6C breaker (example of tip attachment)
6D fork (example of tip attachment)
8 Arm Cylinder 10 Option Cylinder 21 First Hydraulic Pump 22 Second Hydraulic Pump 23 Pilot Pump 30 Turning Motor 70 Control Device 71 Displacement Control Section 72 Torque Calculation Section 81a Turning Operation Lever (an example of turning operation member)
82a Arm operating lever (an example of an attachment operating member)
83a Option operation lever (an example of an attachment operation member)
90 Turning speed detection unit 91 Discharge pressure detection unit 92 Inclination detection unit 93 Differential pressure detection unit 94 Turning operation direction detection unit 95 Arm operation direction detection unit 96 Option operation direction detection unit 100 Construction machine L41 First port line (hydraulic oil supply oil or hydraulic oil return oil passage)
L42 Second port line (hydraulic oil supply passage or hydraulic oil return passage)

Claims (7)

construction machinery,
a substrate;
an upper rotating body rotatably mounted on the base;
an attachment mounted on the upper revolving body;
a hydraulic pump that discharges hydraulic oil;
a variable displacement swing motor that receives supply of the hydraulic oil discharged from the hydraulic pump and operates to swing the upper swing structure;
an actuator that operates to operate at least a portion of the attachment by receiving the supply of the hydraulic oil discharged from the hydraulic pump;
a turning operation member that receives a turning operation for turning the upper turning body;
an attachment operation member that receives an attachment operation for operating at least part of the attachment;
When the turning operation is performed but the attachment operation is not performed, control is performed to adjust the capacity of the turning motor to a preset first capacity, and the turning operation is performed. a displacement control unit configured to perform control for adjusting the displacement of the swing motor to a second displacement larger than the first displacement during a combined operation in which the and the attachment operation are simultaneously performed;
a discharge pressure detection unit for detecting the discharge pressure of the hydraulic pump ,
When the discharge pressure detected by the discharge pressure detection unit is less than a preset discharge pressure threshold value, the displacement control unit sets the displacement of the turning motor at the time of the combined operation to the second displacement. On the other hand, when the discharge pressure detected by the discharge pressure detection unit is equal to or higher than the discharge pressure threshold value, the displacement of the swing motor during the combined operation is set to the second displacement. A construction machine configured to have a control to adjust to a capacity less than construction machinery,
a substrate;
an upper rotating body rotatably mounted on the base;
an attachment mounted on the upper revolving body;
a hydraulic pump that discharges hydraulic oil;
a variable displacement swing motor that receives supply of the hydraulic oil discharged from the hydraulic pump and operates to swing the upper swing structure;
an actuator that operates to operate at least a portion of the attachment by receiving the supply of the hydraulic oil discharged from the hydraulic pump;
a turning operation member that receives a turning operation for turning the upper turning body;
an attachment operation member that receives an attachment operation for operating at least part of the attachment;
When the turning operation is performed but the attachment operation is not performed, control is performed to adjust the capacity of the turning motor to a preset first capacity, and the turning operation is performed. a displacement control unit configured to perform control for adjusting the displacement of the swing motor to a second displacement larger than the first displacement during a combined operation in which the and the attachment operation are simultaneously performed;
a tilt detection unit for detecting the tilt of the construction machine ,
The displacement control unit sets the displacement of the swing motor to the second displacement during the combined operation when the inclination of the construction machine detected by the inclination detection unit is less than a preset inclination threshold value. On the other hand, when the tilt of the construction machine detected by the tilt detector is equal to or greater than the tilt threshold value, the displacement of the swing motor during the combined operation is set to the second displacement. A construction machine configured to have a control to adjust to a capacity less than construction machinery,
a substrate;
an upper rotating body rotatably mounted on the base;
an attachment mounted on the upper revolving body;
a hydraulic pump that discharges hydraulic oil;
a variable displacement swing motor that receives supply of the hydraulic oil discharged from the hydraulic pump and operates to swing the upper swing structure;
an actuator that operates to operate at least a portion of the attachment by receiving the supply of the hydraulic oil discharged from the hydraulic pump;
a turning operation member that receives a turning operation for turning the upper turning body;
an attachment operation member that receives an attachment operation for operating at least part of the attachment;
When the turning operation is performed but the attachment operation is not performed, control is performed to adjust the capacity of the turning motor to a preset first capacity, and the turning operation is performed. a displacement control unit configured to perform control for adjusting the displacement of the swing motor to a second displacement larger than the first displacement during a combined operation in which the and the attachment operation are simultaneously performed;
an inclination detector for detecting an inclination of the construction machine;
a turning operation direction detection unit for detecting an operation direction of the turning operation received by the turning operation member ;
The capacity control unit
When the tilt of the construction machine detected by the tilt detection unit is less than a preset tilt threshold, or when the tilt of the construction machine detected by the tilt detection unit and the tilt of the construction machine detected by the turning operation direction detection unit If the turning direction of the upper turning body obtained based on the operation direction of the turning operation is not the turning and dropping direction that is the direction including the component of the direction of gravity, the capacity of the turning motor at the time of the combined operation is set to while controlling to adjust to a capacity of 2,
The tilt of the construction machine detected by the tilt detector is equal to or greater than the tilt threshold, and the tilt of the construction machine detected by the tilt detector and the turning operation detected by the turning operation direction detector. When the turning direction of the upper turning body obtained based on the operation direction of is the turning drop direction, the capacity of the turning motor during the combined operation is adjusted to be smaller than the second capacity. construction equipment configured to control the construction machinery,
a substrate;
an upper rotating body rotatably mounted on the base;
an attachment mounted on the upper revolving body;
a hydraulic pump that discharges hydraulic oil;
a variable displacement swing motor that receives supply of the hydraulic oil discharged from the hydraulic pump and operates to swing the upper swing structure;
an actuator that operates to operate at least a portion of the attachment by receiving the supply of the hydraulic oil discharged from the hydraulic pump;
a turning operation member that receives a turning operation for turning the upper turning body;
an attachment operation member that receives an attachment operation for operating at least part of the attachment;
When the turning operation is performed but the attachment operation is not performed, control is performed to adjust the capacity of the turning motor to a preset first capacity, and the turning operation is performed. a displacement control unit configured to perform control for adjusting the displacement of the swing motor to a second displacement larger than the first displacement during a combined operation in which the and the attachment operation are simultaneously performed;
a differential pressure detection unit for detecting a differential pressure between a hydraulic oil supply passage and a hydraulic oil return passage connected to the swing motor;
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 capacity,
The capacity control section adjusts the capacity of the swing motor during the combined operation to the second capacity when the provisional swing torque calculated by the torque calculation section is less than a preset torque threshold. On the other hand, when the provisional turning torque calculated by the torque calculation unit is equal to or greater than the torque threshold, the capacity of the turning motor during the combined operation is set higher than the second capacity. A construction machine configured with a control for adjusting to a smaller capacity. The construction machine according to any one of claims 1 to 4 ,
further comprising a turning speed detection unit for detecting a turning speed of the upper turning body;
The displacement control unit adjusts the displacement of the swing motor during the combined operation to the second displacement when the swing speed detected by the swing speed detection unit is less than a preset speed threshold. On the other hand, if 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 during the combined operation is set higher than the second capacity. A construction machine configured with a control for adjusting to a smaller capacity. The construction machine according to any one of claims 1 to 5 ,
The attachment includes a boom that is supported on the upper rotating body so as to be able to rise and fall, an arm that is rotatably connected to the tip of the boom, and a tip attachment that is linked to the tip of the arm,
the actuator is an actuator that operates to move the arm;
The construction machine, wherein the attachment operation is an operation for operating the arm. The construction machine according to any one of claims 1 to 5 ,
The attachment includes a boom that is supported on the upper rotating body so as to be able to rise and fall, an arm that is rotatably connected to the tip of the boom, and a tip attachment that is linked to the tip of the arm,
the actuator is an actuator that operates to move the tip attachment;
The construction machine, wherein the attachment operation is an operation for operating the tip attachment.

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