JP6180764B2 - Hydraulic circuit for construction machine and control method thereof - Google Patents

Description

  The present invention relates to a hydraulic circuit of a construction machine and a control method thereof.

  Some hydraulic circuits of construction machines use left and right traveling devices (for example, a left traveling hydraulic motor and a right traveling hydraulic motor) using pressure oil discharged from a hydraulic pump, respectively. Some hydraulic circuits of construction machines control the flow rate of hydraulic oil supplied to the left and right traveling devices (hydraulic motors) when the traveling direction (traveling direction) is changed.

  In Patent Document 1, when a turn operation is performed from a high-speed straight traveling, in order to decelerate from a high speed to a low speed at the start of the turn operation, the operation of the left travel lever (travel operation lever) and the right travel lever are detected, A technique for controlling the left traveling motor (hydraulic motor) and the right traveling motor to drive at low speed is disclosed.

JP 2012-57757 A

  However, in the technique disclosed in Patent Document 1, in order to change the traveling direction during traveling, when the traveling lever on the inner ring side is returned and only the traveling device (hydraulic motor) on the inner ring side is decelerated, The travel direction may be difficult to change unless the operating lever for traveling on the inner ring side is largely returned. In construction machinery, especially when operating the operating lever for right traveling and the operating lever for left traveling with one hand, it is necessary to support the operating lever for traveling on the outer ring side, so the operating lever for traveling on the inner ring side May not be greatly restored. That is, when the traveling direction is changed during traveling, the operability of the construction machine may be reduced.

  The present invention has been made under such circumstances, and in a hydraulic circuit of a construction machine that controls the operation of left and right traveling hydraulic motors using pressure oil discharged from a hydraulic pump, The difference (left-right difference) between the operation amounts input to the operation lever and the right-side operation lever is calculated, and the rotational speed of the inner-wheel-side traveling hydraulic motor is decelerated based on the calculated left-right difference. An object of the present invention is to provide a hydraulic circuit of a construction machine that can be used or a control method thereof.

According to one aspect of the present invention, there is provided a hydraulic circuit for a construction machine that controls operation of a left traveling hydraulic motor and a right traveling hydraulic motor using pressure oil discharged from a hydraulic pump, respectively. A left travel operation lever and a right travel operation lever to which an operation amount of the travel hydraulic motor and an operation amount of the right travel hydraulic motor are input, and the left travel operation lever and the right travel operation lever, respectively. Control means for controlling the left traveling hydraulic motor and the right traveling hydraulic motor based on the input operation amount, and the control means includes the left traveling operation lever and the right traveling hydraulic motor. When the operation lever is operated in the same direction, a left-right difference between the operation amounts input to the left travel operation lever and the right travel operation lever is calculated, and based on the calculated left-right difference Change the direction of travel Whether the judged, on the basis of the left travel operation lever and the operation amount input to each of the right travel control lever and the said difference between right and left when a decision is made to change the direction of travel, the left The correction value is calculated so as to decelerate from the rotational speed of the inner-wheel-side traveling hydraulic motor corresponding to the operation amount of the inner-wheel-side lever of the traveling-operation lever and the right-running operation lever, and the calculated correction There is provided a hydraulic circuit for a construction machine, characterized in that the value is used to reduce the rotational speed of a traveling hydraulic motor on the inner ring side. In addition, at least two hydraulic pumps are provided, the left traveling hydraulic motor is driven using the pressure oil discharged from the first hydraulic pump, and the pressure oil discharged from the second hydraulic pump is used to A right traveling hydraulic motor is configured to be driven, and when the control unit determines to change the traveling direction, the control unit determines whether the first hydraulic pump or the second hydraulic pump is based on the left / right difference. Even in a hydraulic circuit of a construction machine, the discharge flow rate of a hydraulic pump corresponding to the inner ring side traveling hydraulic motor is reduced to reduce the rotational speed of the inner ring side traveling hydraulic motor. Good. The control means calculates an average value of the operation amounts input to the left travel operation lever and the right travel operation lever, calculates a correction value using the left-right difference and the average value, and calculates The hydraulic circuit of the construction machine may reduce the discharge flow rate of the hydraulic pump corresponding to the traveling hydraulic motor on the inner ring side by reducing the flow rate command value using the corrected value. . The control means may be a hydraulic circuit for a construction machine, characterized in that the travel direction is determined to be changed when the left-right difference is equal to or greater than a predetermined value.

According to another aspect of the present invention, the construction machine control method controls the operations of the left traveling hydraulic motor and the right traveling hydraulic motor, respectively, using the pressure oil discharged from at least two hydraulic pumps. An operation input step in which operation amounts are respectively input by a left travel operation lever and a right travel operation lever in order to operate the left travel hydraulic motor and the right travel hydraulic motor; When the travel operation lever and the right travel operation lever are operated in the same direction, a left-right difference between the operation amounts input to the left travel operation lever and the right travel operation lever is calculated. left and right difference calculating step, calculated on the basis of the difference between right and left, the traveling direction determination step of determining whether to change the traveling direction of the construction machine, when a decision is made to change the direction of travel, Serial based the operation amount input to each of the left travel control lever and the right travel operation lever and the said left-right difference, the inner side of the left travel control lever and the right travel operation lever The correction value is calculated so as to decelerate from the rotational speed of the inner-wheel traveling hydraulic motor corresponding to the lever operation amount, and the calculated correction value is used to determine the hydraulic pump corresponding to the inner-wheel traveling hydraulic motor. There is provided a construction machine control method including a travel direction changing step of reducing a discharge flow rate and decelerating a rotation speed of the traveling hydraulic motor on the inner ring side. The operation input step may be a hydraulic circuit control method in which the operation amount is input with one hand by an operator using the left travel operation lever and the right travel operation lever. .

  According to the hydraulic circuit of the construction machine or the control method thereof according to the present invention, the left-right difference between the operation amounts input to the left travel operation lever and the right travel operation lever is calculated, and based on the calculated left-right difference. The rotational speed of the traveling hydraulic motor on the inner ring side can be reduced.

1 is a schematic external view showing an example of a construction machine according to an embodiment of the present invention. 1 is a schematic hydraulic circuit diagram illustrating an example of a hydraulic circuit of a construction machine according to an embodiment of the present invention. It is explanatory drawing explaining an example of the cab room of the construction machine which concerns on the Example of this invention.

  Non-limiting exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the description of all attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show the relative ratio between members or parts. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

  Hereinafter, the present invention will be described using the construction machine 100 according to the embodiment. Note that the present invention is not limited to this embodiment, as long as it is a construction machine provided with a hydraulic circuit for controlling left and right traveling devices (for example, crawler hydraulic motors) using the pressure oil discharged from the hydraulic pump. It can also be used for things. Construction machines that can use the present invention include hydraulic excavators, crane trucks, bulldozers, wheel loaders and dump trucks, pile driving machines, pile removers, water jets, mud drainage treatment equipment, grout mixers, deep Includes foundation and drilling machines.

  The present invention will be described in the order shown below.

1. Construction machine construction 2. Hydraulic circuit of construction machinery Hydraulic circuit control method (change direction operation)
4). Example (cab interior operation)
[1. Construction machine construction]
A schematic configuration of the construction machine 100 according to the present embodiment will be described with reference to FIG. In FIG. 1, as viewed from the operator (driver, operator) seated in the driver's seat, the arrow X1 direction is the forward direction, the arrow X2 direction is the backward direction, the arrow Z1 direction is the upward direction, and the arrow Z2 direction is the Indicates downward direction.

  As shown in FIG. 1, the construction machine 100 according to the present embodiment includes an upper swing body 110Up on which a cab (operator's cab) 110Cb is mounted, and a lower traveling body 110Dw that moves the construction machine 100 using wheels and the like. Prepare. Further, the construction machine 100 includes, as work attachments, a boom 111 whose base end is pivotally supported by the upper swing body 110Up, an arm 112 pivotally supported by the distal end of the boom 111, and a pivot supported by the distal end of the arm 112. The bucket 113 is provided. Further, the construction machine 100 uses, as hydraulic actuators, a boom cylinder 111c that drives the boom 111, an arm cylinder 112c that drives the arm 112, a bucket cylinder 113c that drives the bucket 113, and the upper swing body 110Up as the lower traveling body 110Dw. A turning hydraulic motor 114m that rotates counterclockwise or clockwise (turning operation), and a left traveling hydraulic motor and a right traveling hydraulic motor that are crawler hydraulic motors of the lower traveling body 110Dw. Prepare.

  The construction machine 100 according to the present embodiment extends and contracts the boom cylinder 111c in the longitudinal direction by supplying hydraulic oil (pressure oil) to the boom cylinder 111c using a hydraulic circuit 10 (FIG. 2) described later. At this time, the boom 111 is driven in the vertical direction in front of and above the cab 110Cb by expansion and contraction of the boom cylinder 111c. Further, the construction machine 100 controls the boom direction control valve in accordance with the operation amount and operation direction of the operator's operation lever (such as 26-1 in FIG. 2) in the cabin of the cab 110Cb, and is supplied to the boom cylinder 111c. Control hydraulic fluid. As a result, the construction machine 100 performs a desired operation according to the operation amount of the operation lever of the operator.

  As in the case of the boom 111, the construction machine 100 drives the arm 112 and the bucket 113 in front of and / or above the cab 110Cb by expansion and contraction of the arm cylinder 112c and the bucket cylinder 113c. As in the case of the boom cylinder 111c, the construction machine 100 controls the hydraulic oil supplied to the arm cylinder 112c and the bucket cylinder 113c by the arm direction control valve and the bucket direction control valve.

  In addition, the construction machine 100 according to the present embodiment travels (moves back and forth and from side to side) using the traveling hydraulic motors (the left traveling hydraulic motor and the right traveling hydraulic motor) of the lower traveling body 110Dw. I do. For example, when the traveling direction is changed, the construction machine 100 travels while changing the direction of the construction machine 100 by decelerating the inner ring side of the traveling hydraulic motor and / or accelerating the outer ring side. Here, the change of the running direction is a right turn, a left turn, a right turn, a left turn, a turn, and other direction change (steering) operations. The construction machine 100 (hydraulic circuit 10 in FIG. 2 described later) according to the present embodiment changes the traveling direction based on the operation amount and the operation direction of the traveling operation lever (traveling operation lever) input by the operator. Judge whether to do. In addition, when the construction machine 100 (hydraulic circuit 10) determines to change the traveling direction, the rotation speed of the hydraulic motor on the inner ring side is determined according to the operation amount and the operation direction of the operating lever input by the operator. To control. A control method in which the construction machine 100 (hydraulic circuit 10) changes the traveling direction will be described later [3. Control method of hydraulic circuit].

[2. Hydraulic circuit of construction machinery]
The hydraulic circuit 10 of the construction machine 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic hydraulic circuit diagram illustrating an example of the hydraulic circuit 10 according to the present embodiment.

  2 indicates an oil passage (pressure oil passage). A solid line to which // is added indicates an electric control system. The double solid line indicates the mechanical power system.

  FIG. 2 shows a hydraulic circuit in which two hydraulic pumps (first hydraulic pump 14L and second hydraulic pump 14R) are arranged. However, the hydraulic circuit includes at least two hydraulic pumps and is discharged from the first hydraulic pump. Any hydraulic circuit configured to drive the left traveling hydraulic motor using the pressurized oil and to drive the right traveling hydraulic motor using the pressure oil discharged from the second hydraulic pump. The present invention can also be used for these hydraulic circuits.

  As shown in FIG. 2, the hydraulic circuit 10 is supplied with hydraulic pumps 14L and 14R that discharge pressure oil (hydraulic oil) and pressure oil discharged from the hydraulic pumps 14L and 14R via hydraulic lines 16L and 16R. And a control valve unit 17 having a plurality of directional control valves.

  The hydraulic circuit 10 according to the present embodiment inputs the regulators 13R and 13L according to the operation amount and operation direction of the operation levers 26-1 to 26- (n-1) and 26- (n) input by the operator. To control the electrical signal (flow rate indication value). Thereby, the hydraulic circuit 10 can control (change) the discharge flow rates of the hydraulic pumps 14L and 14R. Further, the hydraulic circuit 10 supplies (inputs) the pressure oil discharged from the hydraulic pumps 14L and 14R to the control valve unit 17 by controlling the operations of the hydraulic pumps 14L and 14R. As a result, the hydraulic circuit 10 starts from each direction control valve of the control valve unit 17 to a hydraulic cylinder (111c, 112c and 113c in FIG. 1) or a traveling hydraulic motor (left traveling hydraulic motor 110SL, right traveling hydraulic pressure). The flow rate and the flow direction of hydraulic oil (pressure oil) supplied (inflow) to the motor 110SR) or the turning hydraulic motor (114m in FIG. 1) can be controlled. That is, the hydraulic circuit 10 can control the driving speed and driving direction of the hydraulic cylinder 111c or the like, or the left traveling hydraulic motor 110SL, the right traveling hydraulic motor 110SR, or the turning hydraulic motor 114m.

  The hydraulic pumps 14L and 14R discharge pressure oil (operating oil) supplied to the hydraulic cylinder (111c or the like). In the present embodiment, the hydraulic pumps 14L and 14R are mechanically connected to the output shaft of the engine 11 serving as the power source, and discharge the pressure oil using the power from the power source.

  Each direction control valve of the control valve unit 17 is a hydraulic oil (hydraulic oil) supplied to the boom cylinder 111c, the arm cylinder 112c, the bucket cylinder 113c, the traveling hydraulic motors 110SL, 110SR, and the turning hydraulic motor 114m. It controls the flow rate and flow direction. In FIG. 2, the spool shape of each direction control valve of the control valve unit 17 is omitted.

  Each direction control valve of the control valve unit 17 controls the flow rate and flow direction of the pressure oil supplied to the hydraulic cylinder (or hydraulic motor) based on the pilot pressure (remote control pressure) input to the control port. Specifically, the spool shape of each directional control valve of the control valve unit 17 includes an internal passage for supplying pressure oil (hydraulic oil) to the hydraulic cylinder, and return oil from the hydraulic cylinder (or hydraulic motor). An internal passage for discharging into the tank is provided. Each directional control valve of the control valve unit 17 receives the pressure of the hydraulic oil discharged from the pilot pump 15 (pilot pressure), switches the spool position according to the input pilot pressure, and changes the path of the internal passage. Change. Each direction control valve of the control valve unit 17 corresponds to the operation amount (and operation direction) of the operation lever (26-1 to 26-n in the figure) operated by the operator by the control means 30 (excavator controller) described later. The pilot pressure is input and the flow rate (operation amount) and flow direction (operation direction) of the pressure oil supplied to the hydraulic cylinder (or hydraulic motor) are changed.

  The hydraulic cylinder (such as 111c in FIG. 1) drives the attachment (such as 111 in FIG. 1) by its expansion and contraction operation. As shown in FIG. 1, in the construction machine 100 of this embodiment, the hydraulic cylinder includes a boom cylinder 111 c that drives the boom 111, an arm cylinder 112 c that drives the arm 112, and a bucket cylinder 113 c that drives the bucket 113. Prepare. The hydraulic cylinder expands and contracts in the longitudinal direction using pressure oil (operating oil) supplied from each direction control valve of the control valve unit 17. Thereby, the hydraulic cylinder drives the attachment. The return oil (hydraulic oil) from the hydraulic cylinder is discharged to a tank or the like via each direction control valve of the control valve unit 17. The hydraulic cylinder can be composed of a cylinder container and a piston.

  The travel hydraulic motor (left travel hydraulic motor 110SL, right travel hydraulic motor 110SR) drives (moves, rotates) a travel device (for example, a crawler) by rotation of its output shaft. The turning hydraulic motor (114m in FIG. 1) drives the upper turning body (110Up in FIG. 1) by the rotation of its output shaft (turns relative to the lower traveling body 110Dw). The hydraulic circuit 10 of the construction machine 100 according to the present embodiment controls hydraulic oil (pressure oil) supplied to the left traveling hydraulic motor 110SL and the right traveling hydraulic motor 110SR by controlling the discharge flow rates of the hydraulic pumps 14L and 14R, respectively. ) Respectively. Thus, the hydraulic circuit 10 can control the operations (rotational speed and direction) of the left traveling hydraulic motor 110SL and the right traveling hydraulic motor 110SR. The hydraulic circuit 10 may control the discharge flow rates of the hydraulic pumps 14L and 14R by controlling regulators 13L and 13R (tilt angles), which will be described later.

  The regulators 13L and 13R are mechanisms for controlling the discharge flow rate per rotation of the hydraulic pumps 14L and 14R. The regulators 13L and 13R include, for example, a tilt actuator, a spool valve mechanism, a horsepower control proportional valve, and a feedback lever.

  The tilt actuator is a functional element that tilts and drives a swash plate (yoke) for changing the pump capacity of the hydraulic pumps 14L and 14R. The tilting actuator includes an operating piston having a large diameter pressure receiving portion at one end and a small diameter pressure receiving portion at the other end, a pressure receiving chamber corresponding to the large diameter pressure receiving portion, and a pressure receiving chamber corresponding to the small diameter pressure receiving portion. The spool valve mechanism is a functional element for supplying and discharging hydraulic oil to and from the pressure receiving chamber of the tilt actuator. The spool valve mechanism includes, for example, a spool valve and a spring. The horsepower control proportional valve is a functional element for displacing the spool valve. The horsepower control proportional valve uses the pressure oil discharged from the pilot pump 15 to generate a secondary side pressure corresponding to the command current (flow command value) from the control means 30. The horsepower control proportional valve operates so that, for example, the secondary side pressure increases as the command current increases. The feedback lever is a link mechanism for feeding back the displacement of the tilting actuator to the spool valve. For example, when the operating piston moves, the feedback lever physically feeds back the movement amount to the spool valve, and controls the spool valve to return to the neutral position.

  The control means 30 is a means for controlling the overall operation of the hydraulic circuit 10. The control unit 30 controls the hydraulic pumps 14L and 14R, the regulators 13L and 13RL, and the like according to information input to the hydraulic circuit 10. The control means 30 determines an electrical signal (flow command value) to be input to the hydraulic pumps 14L, 14R (regulators 13L, 13R) based on, for example, pressures (negative control pressures) detected by the negative control pressure sensors 29L, 29R. Further, the control means 30 controls the tilt angles of the regulators 13L and 13R by inputting the determined electrical signals (flow rate instruction values) to the regulators 13L and 13R. Thereby, the control means 30 controls the discharge flow rates of the hydraulic pumps 14L and 14R according to the tilt angles of the regulators 13L and 13R (negative control).

  Further, when changing the traveling direction, the control means 30 decelerates the hydraulic motor on the inner ring side in the left traveling hydraulic motor 110SL and the right traveling hydraulic motor 110SR, and changes the direction of the construction machine 100. Further, when changing the traveling direction, the control means 30 further accelerates the hydraulic motor on the outer ring side in the left traveling hydraulic motor 110SL and the right traveling hydraulic motor 110SR to change the direction of the construction machine 100. Good. A control method in which the control means 30 of the hydraulic circuit 10 changes the traveling direction will be described later [3. Control method of hydraulic circuit].

  The control means 30 may use, for example, an excavator controller provided in advance for controlling the operation of the construction machine 100. Here, the shovel controller can be configured by an arithmetic processing device including a CPU (Central Processing Unit) and a memory (ROM, RAM, etc.).

[3. Control method of hydraulic circuit]
A travel direction changing method (control method) performed by the control means 30 in the hydraulic circuit 10 of the construction machine 100 according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 2, the control means 30 of the hydraulic circuit 10 according to the present embodiment is first operated by an operator with an operation lever 26-(n) for left travel and an operation lever 26-(n−1) for right travel. ) And the operation amount (and operation direction) are respectively input (operation input step). At this time, the control means 30 determines the difference between the input operation amount of the left travel operation lever 26- (n) and the operation amount of the right travel operation lever 26- (n-1) (hereinafter, “left and right”). (Referred to as “difference”) (left-right difference calculation step).

  Next, the control means 30 controls the left travel operation lever 26- (n) and the right travel operation lever 26- (n) with the intention of the operator to change the travel direction based on the calculated left / right difference in the operation amount. -1) is judged (operation direction judgment step). The control means 30 can determine that the traveling direction is changed when the left-right difference in the calculated operation amount is equal to or greater than a predetermined value.

  Here, the predetermined value is a value corresponding to the specifications of the traveling hydraulic motors 110SL and 110SR, the hydraulic pumps 14L and 14R, and other construction machines 100. In addition, the predetermined value is used when calculating the average value of the operation amounts respectively input to the left travel operation lever 26- (n) and the right travel operation lever 26- (n-1). It can be a value corresponding to the calculated average value. Furthermore, the predetermined value can be a value determined in advance by experiment or calculation.

  Next, when it is determined that the travel direction is to be changed, the control means 30 controls the rotational speed of the hydraulic motor on the inner ring side according to the operation amount and the operation direction of the travel operation lever input by the operator (travel). Direction change step). Specifically, the control means 30 first specifies the traveling hydraulic motor on the inner ring side based on the calculated left-right difference. Next, the control means 30 decreases the discharge flow rate of the hydraulic pump corresponding to the identified traveling hydraulic motor on the inner ring side. Thereby, the control means 30 can decelerate the rotational speed of the hydraulic motor for traveling on the inner ring side.

  Further, the control means 30 calculates a correction value (a value for correcting the flow rate command value) using the calculated left-right difference and average value. Specifically, the control means 30 determines a basic correction value based on the calculated left-right difference, and calculates the left travel operation lever 26- (n) and the right travel operation lever 26- (n-1). ) And the basic correction value are corrected by a coefficient corresponding to the average value of the manipulated variables respectively input to the correction values. This coefficient has such a characteristic that it increases as the average value of the manipulated variables increases. Next, the control means 30 uses the calculated correction value to reduce the flow rate command value input to the regulator corresponding to the traveling hydraulic motor for the inner ring side. As a result, the control means 30 may reduce the discharge flow rate of the hydraulic pump corresponding to the traveling hydraulic motor on the inner ring side and decelerate the rotational speed of the traveling hydraulic motor on the inner ring side.

  As described above, according to the hydraulic circuit 10 (control unit 30) of the construction machine 100 or the control method thereof according to the embodiment of the present invention, the traveling direction of the construction machine 100 can be changed. Further, according to the hydraulic circuit 10 or the control method thereof according to the present embodiment, the difference (left-right difference) between the operation amounts input to the left travel operation lever and the right travel operation lever is calculated. Whether or not to change the traveling direction can be determined based on the left-right difference. Furthermore, according to the hydraulic circuit 10 or the control method thereof according to the present embodiment, when it is determined that the traveling direction is to be changed, the operation amount (the average value of the operation amount) of the left traveling operation lever and the right traveling operation lever. ) And the calculated left-right difference, the rotational speed of the hydraulic motor for traveling on the inner ring side can be reduced. That is, according to the hydraulic circuit 10 or the control method thereof according to the present embodiment, the rotation speed of the traveling hydraulic motor on the inner ring side can be reduced, so that the operation lever corresponding to the traveling hydraulic motor on the inner ring side Even when the operation amount is small, the traveling direction of the construction machine 100 can be easily changed.

  This invention is demonstrated using the construction machine which concerns on Example 1 of FIG. Here, FIG. 3 is an explanatory diagram illustrating an example of the cab room 122 of the construction machine according to the present embodiment. In FIG. 3, as viewed from the operator seated on the driver's seat 120S, the arrow X1 direction is the forward direction, the arrow X2 direction is the backward direction, the arrow Y1 direction is the left direction, the arrow Y2 direction is the right direction, and the arrow Z1 direction Indicates the upward direction, and the arrow Z2 direction indicates the downward direction. In addition, operation levers 123L, 123R and the like for receiving a driving operation are provided in front of the driver seat 120S.

  Since the construction of the construction machine and the hydraulic circuit according to the present embodiment are the same as the construction of the construction machine 100 according to the embodiment, the description thereof is omitted.

  As shown in FIG. 3, the construction machine according to the present embodiment includes a pair of left and right traveling operation levers 123L and 123R, a pair of left and right foot pedals 124L and 124R, and other operation devices 125L and 125R. Here, the left travel operation lever 123L corresponds to the left travel operation lever 26- (n) shown in FIG. The right travel operation lever 123R corresponds to the right travel operation lever 26- (n-1) shown in FIG.

  The operator tilts the pair of left and right traveling operation levers 123L and 123R forward when the construction machine travels (for example, goes straight). At this time, the construction machine inputs the operation amounts (and operation directions) corresponding to the operations to the left and right traveling hydraulic motors 110SL and 110SR (FIG. 2), respectively. The operator can tilt the left and right traveling operation levers 123L and 123R forward with one hand, for example.

  Next, when the traveling direction of the construction machine is changed, the operator tilts (returns) the traveling operation lever 123L or the operation lever 123R corresponding to the inner ring side backward (operator side). For example, the operator can return one of the pair of left and right operation levers 123L and 123R to the operator side with one hand.

  At this time, the construction machine according to the present embodiment uses the hydraulic circuit 10 (control means 30) to control the rotation speed of the hydraulic motor on the inner ring side according to the operation amount and the operation direction input by the operator ( Driving direction change step). That is, the construction machine according to the present embodiment, like the construction machine according to the embodiment, identifies the inner-wheel-side traveling hydraulic motor based on the calculated left-right difference, and controls the left-side traveling lever and the right-side traveling lever. Based on the operation amount of the control lever (average value of the operation amount) and the calculated left-right difference, the discharge flow rate of the hydraulic pump corresponding to the hydraulic motor for traveling on the inner ring side is reduced, and the hydraulic motor for traveling on the inner ring side Reduce the rotation speed. Thereby, the operator can change the traveling direction of the construction machine 100.

  For example, when the operator returns one of the pair of left and right operation levers 123L and 123R to the operator side with one hand, the inner wheel side operation lever is supported while supporting the outer wheel side operation lever. Can be returned. At this time, since the construction machine according to the present embodiment can decelerate the rotational speed of the traveling hydraulic motor on the inner ring side, the operating lever for traveling on the inner ring side is largely returned (so that the operation amount increases). The same effect as in the case of (input) can be obtained. That is, when the operator changes the direction during traveling, the traveling direction can be easily changed by inputting a small amount of operation, and the operability of the construction machine can be improved. In addition, when the operator operates the left and right traveling operation levers 123L and 123R with one hand, the amount of operation that can be input with one hand is limited. Therefore, the operability can be further improved by using the present invention. .

  In the construction machine according to the present embodiment, when the traveling direction is changed and the operation other than traveling (for example, the operation of the attachment) is performed at the same time, the rotational speed of the traveling hydraulic motor for traveling on the inner ring side is set. Control that does not decelerate may be used.

  As described above, according to the hydraulic circuit of the construction machine according to the first embodiment or the control method thereof, the same effects as those of the hydraulic circuit 10 of the construction machine 100 according to the embodiment or the control method thereof can be obtained.

  As mentioned above, although embodiment and the Example of the hydraulic circuit of the construction machine which concern on this invention, and its control method were described, this invention is not restrict | limited to the embodiment or Example mentioned above. The present invention can be variously modified or changed in light of the appended claims.

  For example, a hydraulic pump may be provided in addition to the hydraulic pumps 14L and 14R to drive a specific hydraulic actuator (for example, a turning hydraulic motor 114m).

  Further, each of the hydraulic pumps 14L and 14R may be constituted by a plurality (for example, two) of hydraulic pumps. In this case, the discharge flow rates of the plurality of hydraulic pumps corresponding to the inner ring side traveling hydraulic motors may all be reduced at the same time, or among the plurality of hydraulic pumps corresponding to the inner ring side traveling hydraulic motors. An arbitrary number (for example, one) of discharge flow rates may be reduced.

100: Construction machine 110Cb: Cab (cab)
110Up: Upper turning body 110Dw: Lower traveling body 110SL, 110SR: Traveling hydraulic motor (traveling hydraulic motor)
111: Boom 111c: Boom cylinder 112: Arm 112c: Arm cylinder 113: Bucket 113c: Bucket cylinder 114m: Hydraulic motor for turning 10: Hydraulic circuit 11: Engine (diesel engine, etc.)
13R, 13L: Regulator 14L, 14R: Hydraulic pump 16L, 16R: Hydraulic line 17: Control valve unit (directional control valve)
26- (n-1), 26- (n), 123R, 123L: Traveling lever (traveling lever)
30: Control means (excavator controller, etc.)

Claims (6)

A hydraulic circuit for a construction machine that controls the operation of a left traveling hydraulic motor and a right traveling hydraulic motor using pressure oil discharged from a hydraulic pump,
A left travel operation lever and a right travel operation lever to which an operation amount of the left travel hydraulic motor and an operation amount of the right travel hydraulic motor are input;
Control means for controlling the left traveling hydraulic motor and the right traveling hydraulic motor based on the operation amounts respectively input to the left traveling operation lever and the right traveling operation lever;
The control means is configured to input the operations input to the left travel operation lever and the right travel operation lever, respectively, when the left travel operation lever and the right travel operation lever are operated in the same direction. A left-right difference between the left and right travel levers and a right-running operation lever when it is determined whether to change the travel direction based on the calculated left-right difference. Based on the operation amount input to each of the levers and the difference between the left and right sides, the inner wheel side travel corresponding to the operation amount of the inner wheel side lever among the left travel operation lever and the right travel operation lever. Calculating a correction value so as to decelerate from the rotational speed of the hydraulic motor, and decelerating the rotational speed of the traveling hydraulic motor on the inner ring side using the calculated correction value ;
A hydraulic circuit of a construction machine characterized by the above. At least two hydraulic pumps are provided, the left traveling hydraulic motor is driven using the pressure oil discharged from the first hydraulic pump, and the right traveling is performed using the pressure oil discharged from the second hydraulic pump. Configured to drive a hydraulic motor,
When the control means determines to change the travel direction, the hydraulic pressure corresponding to the travel hydraulic motor on the inner ring side of the first hydraulic pump and the second hydraulic pump based on the left-right difference. Decreasing the pump discharge flow rate to reduce the rotational speed of the inner ring side traveling hydraulic motor,
The hydraulic circuit for a construction machine according to claim 1, wherein The control means calculates an average value of the operation amounts input to the left travel operation lever and the right travel operation lever, calculates a correction value using the left-right difference and the average value, and calculates The discharge flow rate of the hydraulic pump corresponding to the traveling hydraulic motor on the inner ring side is reduced by reducing the flow rate command value using the corrected value.
The hydraulic circuit for a construction machine according to claim 2, wherein:   4. The construction machine according to claim 1, wherein the control unit determines that the traveling direction is changed when the left-right difference is equal to or greater than a predetermined value. 5. Hydraulic circuit. A construction machine control method for controlling operations of a left traveling hydraulic motor and a right traveling hydraulic motor, respectively, using pressure oil discharged from at least two hydraulic pumps,
In order to operate the left traveling hydraulic motor and the right traveling hydraulic motor, respectively, operation input steps in which operation amounts are respectively input by the left traveling operation lever and the right traveling operation lever;
When the left travel control lever and the right travel operation lever are operated in the same direction, the left-right difference between the operation amounts input to the left travel operation lever and the right travel operation lever is calculated. A left-right difference calculating step to calculate;
A traveling direction determination step for determining whether to change the traveling direction of the construction machine based on the calculated left-right difference; and
Wherein when the running is determined to change the direction, on the basis of the left travel operation lever and the operation amount input to each of the right travel control lever and the said difference between right and left, the left travel control lever and the The correction value is calculated so as to decelerate from the rotation speed of the inner-wheel-side traveling hydraulic motor corresponding to the operation amount of the inner-wheel-side lever of the right-side driving lever, and the inner-wheel side is calculated using the calculated correction value. And a travel direction changing step of reducing a rotational speed of the travel hydraulic motor on the inner ring side by decreasing a discharge flow rate of a hydraulic pump corresponding to the travel hydraulic motor.   6. The construction machine according to claim 5, wherein in the operation input step, the operation amount is input with one hand by an operator using the left traveling operation lever and the right traveling operation lever. Control method.

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