JP2010106487A - Work determination system for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a control not intended by the operator from being performed by an erroneous determination by providing a work determination system for determining a work by a construction machine and controlling the construction machine to suit to the work. <P>SOLUTION: This work determination system comprises a work determination part 56 which stores detected data in a buffer 57, always calculates the average value of the detected data within a predetermined time, and determines an excavating operation based on the average value of the detected data. A first determination reference S1 capable of estimating the start of the excavating operation and a second determination reference S2 capable of defining that a specific operation is performed are set as a reference for determining the excavating operation. When the operation conforms to the second determination reference, a control for excavating operation suitable for the excavating operation is performed. When the operation conforms to the first determination reference but does not conform to the second determination reference, a preliminary control for excavating operation which is a control performed preliminarily for the control for excavating operation is performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention belongs to a technical field of a work determination system in a construction machine that is used in a construction machine such as a hydraulic excavator when performing hydraulic control or engine output control suitable for the work based on the determination of the work.

Generally, a construction machine such as a hydraulic excavator includes a plurality of hydraulic actuators for performing various operations such as excavation and loading, and various hydraulic devices such as a hydraulic pump, an oil tank, and a valve in order to operate the hydraulic actuators. And a hydraulic actuator operating tool (operating lever or operating pedal) operated by an operator. In such a construction machine, conventionally, a hydraulic actuator operating tool, a hydraulic pump discharge pressure, or a hydraulic pressure is used. A technique is known in which the pressure of the actuator is detected, the working conditions and operation of the construction machine are determined based on the detection results, and the engine output control and hydraulic control are performed based on the determination ( (For example, see Patent Documents 1 and 2.)
In Patent Document 1, the working conditions are determined based on the operation of various hydraulic actuator operating tools and the discharge pressure of the hydraulic pump, and the output torque of the engine and the absorption torque of the hydraulic pump are switched according to the working conditions. It is configured as follows.
Further, in Patent Document 2, in order to reduce fuel consumption, the discharged oil from the boom cylinder of the hydraulic excavator is accumulated in the accumulator, while the accumulated oil in the accumulator can be reused. The hydraulic excavator is in a lifting operation based on the pressure difference between the head pressure of the boom cylinder and the rod side pressure, and in response to the determination, from the head side oil chamber of the boom cylinder. It is configured to switch whether the discharged oil is accumulated in the accumulator or discharged to the oil tank.
Republished patent WO2005 / 098148 JP 2008-101414 A

  By the way, in the prior art, when judging the working condition and operation of the construction machine, detection of the discharge pressure of the hydraulic pump, the operation amount of the operation tool, the differential pressure between the rod side pressure of the boom cylinder and the head side pressure, etc. Judgment is made based on whether or not the value exceeds a preset threshold value (predetermined pressure or predetermined amount), and engine output control or hydraulic control is switched based on the determination. However, when the determination is made based on whether or not the detected value exceeds the threshold value in this way, when the detected value fluctuates temporarily due to a transient pressure fluctuation of the hydraulic circuit in the transitional period of the work or an operator's camera shake, etc. There is a possibility that a misjudgment occurs and control unintended by the operator is executed. Therefore, it is proposed to make a determination on the condition that the threshold value is continuously exceeded for a predetermined time, but in this case, there is a problem that response delay occurs and the operability is inferior, and the present invention is here. There is a problem to be solved.

The present invention was created in view of the above-described circumstances to solve these problems, and the invention of claim 1 is a hydraulic actuator that operates based on operation tool operation to perform various operations. In a construction machine comprising: a work determination system for determining a specific work performed by the construction machine and performing hydraulic control and engine output control suitable for the specific work, Load detection means for detecting the load of the actuator, operation detection means for detecting the operation state of the operating tool, and the detection data of these load detection means and operation detection means are stored in a buffer and the average of the detection data within a predetermined time A work determination means for constantly calculating a value or an integral value and determining a specific work based on an average value or an integral value of the detected data. The first determination criterion that can estimate the start of the specific operation and the second determination criterion that can be determined that the specific operation is being performed are set as the determination criterion for the specific operation in the operation determination unit, and the second determination criterion If it conforms to, the specific work control suitable for the specific work is performed. On the other hand, if it conforms to the first criterion but does not conform to the second criterion, the specific work is a preliminary control for the specific work control. It is the work determination system in the construction machine characterized by performing preliminary control.
According to a second aspect of the present invention, there is provided an accumulator for accumulating oil energy of oil discharged from any hydraulic actuator provided in the construction machine in a hydraulic circuit of the construction machine, and the accumulated pressure oil of the accumulator as the hydraulic actuator or other hydraulic pressure. The work determination system controls the pressure accumulation in the accumulator or the reuse of the pressure accumulation oil in the accumulator based on the determination of the specific work by the work determination means. This is a work determination system for a construction machine.

According to the first aspect of the present invention, even if there is a transient fluctuation of the hydraulic circuit pressure or a temporary fluctuation of the detection data due to an operator's camera shake or the like, the determination of the specific work is performed on the detection data that is constantly calculated. Since the determination is performed based on the average value or the integral value, the temporary fluctuation of the detection data can be eliminated, and a highly reliable and accurate determination can be performed. Moreover, the control for specific work suitable for the specific work is not executed only by estimating the start of the specific work based on the first determination criterion, but when it can be determined that the specific operation is being performed based on the second determination criterion. Therefore, it is possible to reliably avoid the execution of the specific work control due to the erroneous determination, and when the start of the excavation work is estimated based on the first determination criterion, the specific work control is performed. By executing the excavation work preliminary control, which is the preliminary control of the excavation work, it is possible to smoothly shift to the excavation work control without delay in response, thus greatly contributing to improvement in workability and operability. it can.
According to the invention of claim 2, in the hydraulic circuit that can collect and reuse the oil energy of the oil discharged from the hydraulic actuator in the accumulator, the accumulator pressure accumulation or the accumulator pressure accumulation oil reuse It is possible to appropriately control according to the specific work performed by the construction machine.

  Next, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a hydraulic excavator that is an example of a construction machine. The hydraulic excavator 1 is a crawler-type lower traveling body 2 and an upper revolving body 3 that is rotatably supported above the lower traveling body 2. The working unit 4 is composed of various parts such as a working unit 4 mounted on the front of the upper swing body 3, and the working unit 4 further includes a boom 5 whose base end portion is supported by the upper swing body 3 so as to swing up and down, A stick 6 supported at the front end of the boom 5 so as to freely swing back and forth, a bucket 7 attached to the front end of the stick 6, a boom cylinder 8 for swinging the boom 5, the stick 6 and the bucket 7, and a stick cylinder 9 respectively. And a bucket cylinder 10 and the like.

  FIG. 2 is a diagram showing a hydraulic circuit provided in the hydraulic excavator 1. In FIG. 2, 11 and 12 are variable displacement type first and second main pumps driven by the engine E, and 13 is a pilot. A pilot pump serving as a hydraulic pressure source, 14 is an oil tank, 15 is a left side traveling motor, 16 is a right side traveling motor, 17 is a turning motor, and 8, 9, and 10 are the boom cylinder, stick cylinder, and bucket cylinder.

  Here, the boom cylinder 8 holds the weight of the working unit 4 by the pressure of the head side oil chamber 8a, and extends by supplying pressure oil to the head side oil chamber 8a and discharging oil from the rod side oil chamber 8b. Then, the boom 5 is raised, and the boom 5 is lowered by being contracted by pressure oil supply to the rod side oil chamber 8b and oil discharge from the head side oil chamber 8a. The working unit 4 as a whole moves up and down as the boom 5 moves up and down, and the potential energy of the working unit 4 increases as the boom 5 moves up. The potential energy is collected in the accumulator 18 as will be described later. Has been reused. The boom cylinder 8 corresponds to a hydraulic actuator according to claim 2 of the present invention.

  The stick cylinder 9 is extended by pressure oil supply to the head side oil chamber 9a and oil discharge from the rod side oil chamber 9b to swing the stick 6 inward (in the direction close to the upper swing body 3). In addition, the stick 6 is reduced by the pressure oil supply to the rod-side oil chamber 9b and the oil discharge from the head-side oil chamber 9a to swing the stick 6 outward (in the direction away from the upper swing body 3). ing. The stick cylinder 9 corresponds to a hydraulic actuator according to claim 1 of the present invention.

  Further, in FIG. 2, reference numeral 19 denotes a control valve unit. The control valve unit 19 includes a left traveling motor 15, a right traveling motor 16, a turning motor 17, a boom cylinder 8, a stick cylinder 9, and a bucket cylinder 10. Control valves 20, 21, 22, 23, 24, 25 for left-side traveling, right-side traveling, turning, boom, stick, and bucket for performing oil supply / discharge control, traveling straight-travel valve 26, main relief valve 27 etc. are arranged.

  The boom control valve 23 is a three-position switching valve having ascending and descending pilot ports 23a and 23b. When the pilot pressure is not input to both the pilot ports 23a and 23b, the boom control valve 23 is connected to the boom cylinder 8. Although it is located at the neutral position N where oil supply / discharge is not performed, the discharge pressure of the first main pump 11 is supplied to the head side oil chamber 8a of the boom cylinder 8 when the pilot pressure is input to the ascending pilot port 23a. On the other hand, switching to the ascending position X where the oil discharged from the rod-side oil chamber 8b flows to the oil tank 14 is performed, and the pilot pressure is input to the descending pilot port 23b. The position is switched to the lower position Y where the discharged oil is supplied to the rod side oil chamber 8b of the boom cylinder 8. In this case, the opening area of the boom control valve 23 at the ascending position X and the descending position Y is configured to increase or decrease in accordance with the increase or decrease of the pilot pressure input to each pilot port 23a, 23b. As will be described later, the boom control valve 23 is switched to the ascending position X when pilot pressure is input to the ascending pilot port 23a when the boom operating tool is operated to the ascending boom side. In this case, the pressure-accumulated oil from the accumulator 18 is combined with the oil discharged from the first main pump 11.

  The stick control valve 24 is a three-position switching valve provided with in-side and out-side pilot ports 24a and 24b. When no pilot pressure is input to the pilot ports 24a and 24b, the stick cylinder 9 However, when the pilot pressure is input to the in-side pilot port 24a, the oil discharged from the second main pump 12 is supplied to the head-side oil chamber 9a of the stick cylinder 9. On the other hand, the second main pump 12 is switched to the in-side position X where the oil discharged from the rod-side oil chamber 9b flows into the oil tank 14 and the pilot pressure is input to the out-side pilot port 24b. Is supplied to the rod side oil chamber 9b of the stick cylinder 9, while from the head side oil chamber 9a. Setsu換Ru the out position Y to flow discharge oil to the oil tank 14. In this case, the opening area of the stick control valve 24 at the in-side position X and the out-side position Y is configured to increase / decrease in accordance with the increase / decrease of the pilot pressure input to each pilot port 24a, 24b.

  Further, the control valves 20, 21, 22, 25 for the left side traveling, right side traveling, turning, and bucket are the pilot ports 20 a, 20 b similarly to the boom control valve 23 and the stick control valve 24 described above. , 21a, 21b, 22a, 22b, 25a, 25b, and based on the input of pilot pressure, the left traveling motor 15, the right traveling motor 16, the turning motor 17, and the bucket cylinder 10 The oil supply / discharge control is switched to the operation position X or Y for performing the oil supply / discharge control.

  On the other hand, 28 and 29 are boom raising and boom lowering electromagnetic proportional pressure reducing valves. These boom raising and boom lowering electromagnetic proportional pressure reducing valves 28 and 29 are boom operating tools (operation lever, not shown). The pilot pressure is output to the ascending and descending pilot ports 23a and 23b of the boom control valve 23 based on the ascending and descending operations. In this case, the pilot pressure is controlled to increase or decrease in accordance with the operation amount of the boom operation tool.

  30 and 31 are stick-in side and stick-out side electromagnetic proportional pressure reducing valves. These stick-in and stick-out side electromagnetic proportional pressure reducing valves 30 and 31 are stick operating tools (operating lever, not shown). The pilot pressure is output to the in-side and out-side pilot ports 24a and 24b of the stick control valve 24 based on the in-side and out-side operations. In this case, the pilot pressure is controlled to increase or decrease according to the operation amount of the stick operation tool.

  Further, although not shown in FIG. 2, the hydraulic circuit of the excavator 1 includes the left side travel, the right side travel, and the turn based on the operation of a corresponding operation tool (operation lever or operation pedal, not shown). , Control valve 20, 21, 22, 25 for bucket, pilot port 20a, 20b, 21a, 21b, 22a, 22b, 25a, 25b for outputting pilot pressure to left side, right side, turning, bucket An electromagnetic proportional pressure reducing valve is provided. And the electromagnetic proportional pressure reducing valves for left side traveling, right side traveling, turning, and bucket, and the boom raising side, boom lowering side electromagnetic proportional pressure reducing valves 28, 29, stick-in side, stick-out side electromagnetic proportional pressure reducing valves Both 30 and 31 are configured to operate in accordance with a control signal output from a control device 34 described later.

  On the other hand, reference numeral 36 denotes a recovery oil passage from the head side oil chamber 8a of the boom cylinder 8 to the accumulator 18, and a recovery valve 37 is disposed in the recovery oil passage 36.

  The recovery valve 37 is a flow rate control valve in which the spool moves based on the operation of the recovery valve electro-hydraulic conversion valve 38 to which a control signal from the control device 34 described later is input. In a non-actuated state 38, the recovery oil passage 36 is located at the closed position N. However, when the recovery valve electric oil conversion valve 38 is operated, the spool moves to open the recovery oil passage 36. It is configured to switch to position X. Further, the recovery valve 37 incorporates a check valve 39 that allows oil flow from the head-side oil chamber 8a of the boom cylinder 8 to the accumulator 18 but prevents reverse flow. Thus, by switching the recovery valve 37 to the open position X, the oil discharged from the head side oil chamber 8a of the boom cylinder 8 can be accumulated in the accumulator 18 via the recovery oil passage 36. It has become.

  Further, 41 is a regeneration oil passage (corresponding to the regeneration circuit of the present invention) from the accumulator 18 to the discharge line 11a of the first main pump 11, and the regeneration oil passage 41 is provided with a regeneration valve 42. Has been.

  The regeneration valve 42 is a flow rate control valve in which the spool moves based on the operation of the regeneration valve electro-hydraulic conversion valve 43 to which a control signal from the control device 34 is input. In the non-operating state, it is located at the closed position N that closes the regenerative oil passage 41, but the open position X that opens the regenerated oil passage 41 when the regenerative valve electro-hydraulic conversion valve 43 is activated to move the spool. It is comprised so that it may switch to. Further, the regenerated oil passage 41 incorporates a check valve 44 that allows oil flow from the accumulator 18 to the discharge line 11a of the first main pump 11 but prevents reverse flow. Thus, when the regeneration valve 42 is switched to the open position X, the accumulated oil in the accumulator 18 can be merged with the discharge oil of the first main pump 11 via the regeneration oil passage 41. Yes.

  Reference numeral 45 denotes a discharge oil passage from the head side oil chamber 8a of the boom cylinder 8 to the oil tank 14, and a discharge valve 46 is disposed in the discharge oil passage 45.

  The discharge valve 46 is a two-position switching valve provided with a pilot port 46a, and in a state where pilot pressure is not input to the pilot port 46a, the discharge valve 46 is positioned at a closed position N that closes the discharge oil passage 45. When the pilot pressure is input to the pilot port 46a, the spool moves to switch to the open position X where the drain oil passage 45 is opened. Thus, when the discharge valve 46 is switched to the open position X, the discharged oil from the head side oil chamber 8a of the boom cylinder 8 can be flowed to the oil tank 14.

  Further, 47 is an electromagnetic proportional pressure reducing valve for the discharge valve. The electromagnetic proportional pressure reducing valve 47 for the discharge valve is connected to the pilot port 46a of the discharge valve 46 based on the control signal inputted from the control device 34. Is configured to output.

  On the other hand, the control device 34 is configured using a microcomputer or the like, and as shown in the block diagram of FIG. 3, for left side running, for right side running, for turning, for booms, for sticks, for buckets. The operation detection means 48 to 53 for the left traveling, the right traveling, the turning, the boom, the stick, and the bucket operation detecting means 48 to 53 for detecting the operation state (operation presence / absence, operation direction, operation amount) of the operation tool, respectively. Signals from a stick head side pressure sensor 54 for detecting the pressure of the head side oil chamber 9a, an accumulator pressure sensor 55 for detecting the pressure of the accumulator 18, and the like are input, and on the basis of these input signals, the above-described boom raising side, boom Decreasing side electromagnetic proportional pressure reducing valves 28, 29, stick-in side, stick-out side electromagnetic proportional pressure reducing valves 30, 31, for left side travel, right side A control signal is output to the electromagnetic proportional pressure reducing valve for the row, the turning, the bucket, the electro oil conversion valve 38 for the recovery valve, the electro oil conversion valve 43 for the regeneration valve, the electromagnetic proportional pressure reducing valve 47 for the discharge valve, etc. Has been.

  Furthermore, 56 is a work determination unit (corresponding to a work determination unit of the present invention) provided in the control device 34, and it is determined whether or not a specific work is being performed in the work determination unit 56. In this embodiment, the excavation work is set as the specific work, and it is configured to determine whether or not the excavation work is performed.

  In determining the excavation work, the work determination unit 56 first determines the work load of the stick cylinder 9 based on the detection values input from the stick head side pressure sensor 54 and the stick operation detection means 52 (the first to be described later). One work load Pw1 and a second work load Pw2) are obtained. The excavation work is normally performed by operating the boom 5, the stick 6, and the bucket 7 in an interlocked manner, but the work load of the stick cylinder 9 is significantly different between when the excavation work is performed and when it is not performed. Therefore, in the present embodiment, the excavation work is determined based on the work load of the stick cylinder 9. In the present embodiment, the stick head side pressure sensor 54 and the stick operation detecting means 52 correspond to the load detecting means and the operation detecting means of the present invention.

  The control procedure for obtaining the work load of the stick cylinder 9 will be described based on the control block diagram shown in FIG. 4. The work determination unit 56 first detects the head side of the stick cylinder 9 detected by the stick head side pressure sensor 54. The pressure Ps of the oil chamber 9a (hereinafter referred to as the stick head side pressure Ps) and the operation amount L of the stick operating tool detected by the stick operation detecting means 52 (hereinafter referred to as the stick operation amount L). The operation amount L is expressed as a percentage in which 0% is set when the stick operating tool is in the neutral position (when it is not operated) and 100% when the stick operating tool is fully operated. ) And (+) when operated to the out side) is input to the buffer 57. The buffer 57 stores the detection data in a time-series manner for a preset first predetermined time T1 (which can be arbitrarily set, for example, 500 to 1000 msec), and data after the first predetermined time T1 has elapsed. It is set to be erased sequentially.

  The detection data stored in the buffer 57 is input to the average / integral value calculator 58. The average value / integral value calculation unit 58 always calculates an average value or an integral value within a predetermined time of the detection data stored in the buffer 57, but in this embodiment, a second predetermined time before the present time. Average value APs2 of stick head side pressure Ps within T2 and average value AL2 of stick operation amount L, and average value APs3 of stick head side pressure Ps and stick operation amount L within a third predetermined time T3 before the present. A value AL3 (the average values APs2, AL2, APs3, and AL3 all do not include the current value) is calculated. The average values APs2, AL2, APs3, and AL3 calculated by the average / integral value calculation unit 58 are output to first and second workload calculation units 59 and 60, which will be described later, for calculating the workload. Used. The second and third predetermined times T2 and T3 are arbitrarily set to be shorter than the first predetermined time T1, but are suitable for obtaining first and second work loads Pw1 and Pw2 to be described later. Set to be time.

The first work load calculation unit 59 includes the average value APs2 of the stick head side pressure Ps and the average value AL2 of the stick operation amount L within the second predetermined time T2 output from the average value / integration value calculation unit 58, the stick The current stick head pressure Ps detected by the head-side pressure sensor 54 is input, and the current work with respect to the average value of the operating load within the second predetermined time T2 before the present is calculated using the following equation (1). A load fluctuation amount Pw1 is obtained.
Pw1 = (| AL2 | / 100) × (Ps−APs2) (1)
When the average value AL2 of the stick operation amount L within the second predetermined time T2 is “0” or more (AL2 ≧ 0, that is, when the stick operation tool is in the neutral position, or is operated to the out side. ), The fluctuation amount Pw1 of the operating load is set to “0” (Pw1 = 0).
Then, based on the fluctuation amount Pw1 of the operating load obtained by the equation (1), it is estimated whether or not excavation work has been started, as will be described later. That is, when the excavation work is started, the work load on the in-side of the stick cylinder 9 is greatly increased. Therefore, it is possible to estimate whether or not the excavation work has been started by obtaining the operating load fluctuation amount Pw1. Hereinafter, the fluctuation amount Pw1 of the operating load obtained by the equation (1) will be referred to as a first work load Pw1.

On the other hand, the second workload calculation unit 60 calculates the average value APs3 of the stick head side pressure Ps and the average value AL3 of the stick operation amount L within the third predetermined time T3 output from the average value / integration value calculation unit 58. The average value Pw2 of the work load within the third predetermined time T3 before the present is obtained using the following equation (2).
Pw2 = (| AL3 | / 100) × APs3) (2)
When the average value AL3 of the stick operation amount L within the third predetermined time T3 is “0” or more (AL3 ≧ 0, that is, when the stick operation tool is in the neutral position, or is operated to the out side. ), The average value Pw2 of the operating load is set to “0” (Pw2 = 0).
Then, based on the average value Pw2 of the operating load obtained by the equation (2), it is determined whether or not the excavation work is performed, as will be described later. That is, when the excavation work is being performed, the work load on the in-side of the stick cylinder 9 is increased. Therefore, the determination of the excavation work can be made reliably by obtaining the average value Pw2 of the operating load. In addition, the average value Pw2 of the working load calculated | required by the said Formula (2) is hereafter called 2nd work load Pw2.

Next, the control procedure for determining the excavation work in the work determination unit 56 will be described with reference to the flowchart shown in FIG.
First, when the system is started, as described above, detection data of the stick head side pressure Ps and the stick operation amount L are input to the buffer 57 (step S1).

  As described above, the average value APs2, AL2, APs3, AL3 is calculated from the detection data input to the buffer 57 by the average value / integration value calculator 58, and these average values APs2, AL2, APs3, AL3 are calculated. Are used to calculate the first and second workloads Pw1 and Pw2 in the first and second workload calculation units 59 and 60 (step S2).

  Next, the work determination unit 56 determines the operation of the stick operation tool (step S3).

  If it is determined in step S3 that the stick operating tool is operated inward or is in the neutral position, it is determined whether or not the excavation flag F is set. (Step S4). Here, the excavation flag F is a flag that is set during execution of “excavation work control” to be described later, and whether or not the “excavation work control” is being executed based on the determination of the excavation flag F. Is judged.

  If it is determined in step S4 that “NO”, that is, “excavation work control” is not being executed (the excavation flag F is not set), the first work load Pw1 is set in advance. It is determined whether or not the set first determination criterion S1 or more (Pw1 ≧ S1?) (Step S5). Here, the first determination criterion S1 is a threshold value of the first work load Pw1 set to estimate the start of excavation work (which can be arbitrarily set, for example, 10000 to 15000 kPa), and the first work When the load Pw1 is equal to or higher than the first determination criterion S1 (Pw1 ≧ S1), it is estimated that the excavation work is started.

  If the determination in step S5 is “YES”, that is, if it is determined that the first work load Pw1 is greater than or equal to the first determination criterion S1 (Pw1 ≧ S1), then the second work load Pw2 is determined in advance. It is determined whether or not (Pw2 ≧ S2?) Whether or not the second determination criterion S2 is set (step S6). Here, the second determination criterion S2 is a threshold value of the second work load Pw2 that is set in order to reliably determine that excavation work is being performed (although it can be arbitrarily set, for example, 5000 to 10000 kPa). If the second work load Pw2 is equal to or greater than the second determination criterion S2, it is determined that the excavation work is being performed.

  If “NO” in the determination of step S6, that is, if the second work load Pw2 is less than the second determination criterion S2 (Pw2 <S2), “excavation work control” is a preliminary control for “excavation work control”. "Preliminary control" is executed (step S7). That is, the start of the excavation work is estimated based on the value of the first work load Pw1, but if it cannot be determined that the excavation work is being performed based on the value of the second work load Pw2, it is a preliminary stage of the excavation work. As a result of the determination, “preliminary control for excavation work” by the control device 34 is executed. The “excavation work preliminary control” will be described later, but after the “excavation work preliminary control” is executed, the process returns to step S1.

  On the other hand, if “YES” is determined in step S6, that is, if the second work load Pw2 is equal to or greater than the second determination criterion S2 (Pw2 ≧ S2), the excavation flag F is set (step S8) and “ "Excavation control" is executed (step S9). That is, when the start of the excavation work is estimated based on the value of the first work load Pw1 and it is determined that the excavation work is being performed based on the value of the second work load Pw2, ”Is determined based on the value of the second work load Pw2, it is determined that the excavation work is being performed, and“ control for excavation work ”is executed by the control device 34. It has become so. The “digging work control” will be described later, but after the “digging work control” is executed, the process returns to step S1.

  If it is determined in step S4 that "YES", that is, "excavation control" is being executed (excavation flag F is set), the second work load is continued. It is determined whether or not Pw2 is greater than or equal to the second determination criterion S2 (Pw2 ≧ S2?) (Step S10).

  If “YES” in the determination in step S10, that is, if the second work load Pw2 is equal to or greater than the second determination criterion S2 (Pw2 ≧ S2), the process proceeds to step S8 and the excavation flag F is set. Along with (Step S8), “control for excavation work” is executed (Step S9). That is, during the execution of “excavation work control”, the “excavation work control” is continued by determining the excavation work based on the value of the second work load Pw.

  On the other hand, if the determination in step S10 is “NO”, that is, if the second work load Pw2 is less than the second determination criterion S2 (Pw2 <S2), the excavation flag F is reset (step S11) and “non- "Excavation control" is executed (step S12). That is, when the excavation work is not determined by the value of the second work load Pw2 during the execution of the “excavation work control”, it is determined that the excavation work has ended, and the process proceeds to the “non-excavation work control”. It has become. The “non-digging work control” will be described later, but after the “non-digging work control” is executed, the process returns to step S1.

  If it is determined in step S3 that the stick operation tool is operated to the out side, or if the determination in step S5 is “NO”, that is, the first work load Pw1 is the first determination. If it is determined that it is less than the reference S1 (Pw1 <S1), the process proceeds to step S11, the excavation flag F is reset (step S11), and “non-excavation work control” is executed ( Step S12). That is, even when the stick operation tool is operated to the out side, or even if it is operated to the in side, “digging work control” is not being executed and excavation is performed according to the value of the first work load Pw1. When the start of work cannot be estimated, it is determined that excavation work is not being performed, and “control for non-digging work” by 34 is executed in the control device.

Thus, when the stick operating tool is operated inward, the start of the excavation work is estimated based on the value of the first work load Pw1, but the excavation work is performed based on the value of the second work load Pw2. If it cannot be determined that the excavation work is in progress, it is determined that the excavation work is in a preliminary stage, and “excavation work preliminary control” is executed. On the other hand, when the start of the excavation work is estimated and the excavation work can be confirmed, or when the excavation work is confirmed during the “preliminary control for excavation work”, the excavation work is performed. Is determined, and “control for excavation work” is executed. Further, while the “excavation work control” is being executed, the “excavation work control” is continued by confirming the excavation work by the value of the second work load Pw2, while if the excavation work is no longer confirmed, “Non-digging work control” is executed.
In the present embodiment, when the “control for excavation work” is shifted from the “control for non-excavation work” to the “control for excavation work” without going through the “preliminary control for excavation work”, the excavation by the value of the first work load Pw1 is performed. The estimation of the start of the work and the confirmation of the excavation work by the value of the second work load Pw2 are the conditions, but depending on the operation speed of the stick operation tool and the values of the first and second determination criteria S1 and S2. It is also conceivable that the excavation work is confirmed before the start of the excavation work is estimated. In such a case, only the confirmation of the excavation work based on the value of the second work load Pw2 is used. It is also possible to shift to “excavation work control” without going through “excavation work preliminary control”.

  Next, the control of the control device 34 based on the operation tool operation will be described. The “non-excavation work control”, “excavation work control”, and “excavation work preliminary control” are described as follows. First, when the boom operation tool is operated to the lowering side of the boom, the control is executed when the boom operation tool is operated (including when the boom operation tool is linked to another hydraulic actuator operation tool). explain.

  When the control device 34 is operated to the boom lowering side, that is, when a boom lowering detection signal is input from the boom operation detecting means 51, the boom control valve is controlled with respect to the boom lowering electromagnetic proportional pressure reducing valve 29. A control signal is output so as to output a pilot pressure to the descending pilot port 23b of the engine 23. As a result, the boom control valve 23 is switched to the lower side position Y, so that the oil discharged from the first main pump 11 is supplied to the rod side oil chamber 8b of the boom cylinder 8 via the boom control valve 23. Is done. The oil supply control to the rod side oil chamber 8b of the boom cylinder 8 is performed in the same manner regardless of the “non-excavation work control”, the “excavation operation preliminary control”, and the “excavation operation control”.

  Further, when the control device 34 is operated to the boom lowering side, the control device 34 performs control to discharge the oil in the head side oil chamber 8a of the boom cylinder 8, and the above-mentioned “non-excavation work control”, “ “Excavation control” and “Excavation preliminary control” are executed. First, “non-excavation work control” will be described. The control device 34 outputs an operation signal to the recovery valve electro-hydraulic conversion valve 38 so as to switch the recovery valve 37 to the open position X. As a result, the recovery valve 37 opens the recovery oil passage 36 from the head side oil chamber 8 a of the boom cylinder 8 to the accumulator 18, and thus the discharged oil from the head side oil chamber 8 a of the boom cylinder 8 accumulates pressure in the accumulator 18. Is done. That is, in the case of “non-excavation work control”, the oil discharged from the head side oil chamber 8a of the boom cylinder 8 is accumulated in the accumulator 18, but in this case, the head side oil chamber of the boom cylinder 8 is stored. The oil discharged from 8a has a high pressure due to the potential energy of the working unit 4, so that the high-pressure oil energy of the discharged oil can be recovered without being wasted. In this case, the lowering speed of the boom 5 is controlled by the opening area of the recovery valve 37. Further, at the time of “control for non-excavation work”, a control signal for pilot pressure output is not output to the electromagnetic proportional pressure reducing valve 47 for the discharge valve, whereby the discharge valve 46 is positioned at the closed position N where the discharge oil passage 45 is closed. Thus, the oil discharged from the head side oil chamber 8 a of the boom cylinder 8 does not flow into the oil tank 14.

  On the other hand, in the case of "control for excavation work", the control device 34 outputs a control signal to the pilot valve 46a of the discharge valve 46 so as to output the pilot pressure to the electromagnetic proportional pressure reducing valve 47 for the discharge valve. As a result, the discharge valve 46 opens the discharge oil passage 45 from the head side oil chamber 8 a of the boom cylinder 8 to the oil tank 14, so that the discharge oil from the head side oil chamber 8 a of the boom cylinder 8 is transferred to the oil tank 14. To be discharged. In other words, in the case of “control for excavation work”, the oil discharged from the head side oil chamber 8a of the boom cylinder 8 is discharged to the oil tank 14, thereby reducing the pressure in the head side oil chamber 8a of the boom cylinder 8. Thus, the lowering operation of the boom 5 during excavation work in which a force that resists the lowering of the boom 5 can be performed smoothly. At the time of “control for excavation work”, an operation signal is not output to the electro-hydraulic conversion valve 38 for the recovery valve, whereby the recovery valve 37 is located at the closed position N for closing the recovery oil passage 36 and the boom The head side oil chamber 8a of the cylinder 8 and the accumulator 18 are in a state of being shut off.

  On the other hand, in the case of “preliminary control for excavation work”, the control device 34 moves the spool of the recovery valve 37 to the position immediately before the open position X with respect to the recovery valve electro-oil conversion valve 38. An operation signal is output. Further, the control device 34 outputs a control signal to the discharge valve electromagnetic proportional pressure reducing valve 47 so as to output a pilot pressure for moving the spool of the discharge valve 46 to a position immediately before the open position X. In this state, the recovery oil passage 36 from the head side oil chamber 8a of the boom cylinder 8 to the accumulator 18 and the discharge oil passage 45 from the head side oil chamber 8a to the oil tank 14 are both closed, and the head side oil chamber 8a. However, the recovery valve 37 or the discharge valve 46 can be immediately positioned at the open position X. That is, in the case of “preliminary control for excavation work”, the oil discharge from the head side oil chamber 8a of the boom cylinder 8 is temporarily stopped and the “preliminary control for excavation work” is changed to “control for non-excavation work”. Alternatively, the recovery valve 37 or the discharge valve 46 can be immediately set to the open position X when shifting to “excavation control”.

  Thus, when the boom 5 is lowered, the oil discharged from the head-side hydraulic pressure 8a of the boom cylinder 8 is determined by the work determination unit 56 as not being excavated, and "non-excavation control" is executed. In the case where the pressure is accumulated in the accumulator 18, it is determined that excavation work is being performed, and when “control for excavation work” is executed, the pressure is discharged to the oil tank 14. Further, when it is determined that the preliminary stage of the excavation work is performed and the “preliminary control for excavation work” is executed, the oil discharge from the head-side oil chamber 8a is temporarily stopped, and immediately the “control for non-excavation work” is performed. Or “excavation control”.

  Next, the control of the control device 34 based on the operation of the operation tool other than the operation of lowering the boom will be described. These controls are the “control for non-excavation work”, “preliminary control for excavation work”, and “for excavation work”. Regardless of “control”, the same operation is performed. First, the case where the boom operation tool is operated to the boom raising side will be described. The control device 34 outputs an operation signal to the regeneration valve electro-hydraulic conversion valve 43 so as to switch the regeneration valve 42 to the open position X. To do. As a result, the regeneration valve 42 opens the regeneration oil passage 41 from the accumulator 18 to the discharge line 11a of the first main pump 11, and the accumulated oil in the accumulator 18 is merged with the discharge oil of the first main pump 11. . In this case, the combined flow rate is controlled by the opening area of the regeneration valve 42.

  Further, when operated to the boom raising side, the control device 34 outputs a control signal to the boom raising side electromagnetic proportional pressure reducing valve 28 so as to output a pilot pressure to the raising side pilot port 23a of the boom control valve 23. . As a result, the boom control valve 23 is switched to the ascending position X, and thus the discharge oil from the first main pump 11 is supplied to the head side oil chamber 8a of the boom cylinder 8 while the rod side oil chamber 8b. The oil is discharged into the oil tank 14 and the boom 5 is raised. In this case, as described above, the accumulated oil of the accumulator 18 is merged with the discharged oil of the first main pump 11, and thus the oil energy recovered in the accumulator 18 when the boom 5 is lowered, It can be reused when the boom rises and can greatly contribute to energy saving. In this case, the discharge flow rate of the first main pump 11 is controlled so as to decrease according to the amount of merging from the accumulator 18 by a variable capacity unit (not shown). Further, since the accumulated oil in the accumulator 18 is merged with the discharge oil of the first main pump 11, for example, when the boom raising side operation and the bucket operation are performed simultaneously, not only the boom cylinder 8 but also the bucket cylinder 10. Is also being supplied.

  Further, when the stick operation tool is operated to the in side, the control device 34 controls the stick-in side electromagnetic proportional pressure reducing valve 30 to output a pilot pressure to the in-side pilot port 24a of the stick control valve 24. Output a signal. As a result, the stick control valve 24 is switched to the in-side position X. Thus, the discharge oil from the second main pump 12 is supplied to the head-side oil chamber 9a of the stick cylinder 9, while the rod-side oil chamber 9b. The oil is discharged into the oil tank 14 and the stick 6 swings inward.

  On the other hand, when the stick operation tool is operated to the out side, the control device 34 controls the stick-out side electromagnetic proportional pressure reducing valve 31 to output a pilot pressure to the out-side pilot port 24b of the stick control valve 24. Output a signal. As a result, the stick control valve 24 is switched to the out-side position Y, so that the oil discharged from the second main pump 12 is supplied to the rod-side oil chamber 9b of the stick cylinder 9, while the head-side oil chamber 9a. The oil is discharged into the oil tank 14 and the stick 6 swings outward.

  Further, when the left side running, right side running, turning, or bucket operation tool is operated, the control device 34 is arranged on the left side with respect to the left side running, right side running, turning, and bucket electromagnetic proportional pressure reducing valves. Control signal is output so that pilot pressure is output to the pilot ports 20a, 20b, 21a, 21b, 22a, 22b, 25a, 25b of the control valves 20, 21, 22, 25 for traveling, right side traveling, turning, and bucket To do. As a result, the left-side travel, right-side travel, turning, and bucket control valves 20, 21, 22, and 25 are switched to the operating position X or Y, and the left-side traveling motor 15, right-side traveling motor 16, and turning motor 17. Pressure oil is supplied to the bucket cylinder 10 so that the lower traveling body 2 moves forward and backward, turns, the upper revolving body 3 turns left and right, or the bucket 10 swings.

  In the present embodiment configured as described, the control device 34 determines the excavation work in the work determination unit 56, and performs hydraulic control suitable for the excavation work based on the determination of the excavation work. In this case, the work determination unit 56 buffers the detection data of the stick head side pressure Ps input from the stick head side pressure sensor 54 and the detection data of the stick operation amount L input from the stick operation detection means 52. And the average value / integral value calculation unit 58 always calculates the average value within the predetermined time (second predetermined time T2, third predetermined time T3) of the latest detection data stored in the buffer 57, Based on the average value, the first work load (the amount of change in the current work load with respect to the average value of the working load within the second predetermined time T2 before the present time) Pw1 and First determination that can estimate the start of excavation work as a reference for determination of excavation work in the work determination unit 56 while obtaining two work loads (average value of the work load within the third predetermined time T3 before this) Pw2 A reference S1 and a second determination criterion S2 that can be determined that excavation work is being performed are set, and if the second determination criterion S2 is satisfied, the “control for excavation operation” is suitable. ”(Control to stop accumulator 18 accumulation and flow the oil in the head side oil chamber 8a of the boom cylinder 8 to the oil tank 14) is executed, while the second determination criterion is met. If it is not suitable, the “excavation work preliminary control” which is the preliminary control of the “excavation work control” (the oil discharge from the head side oil chamber 8a of the boom cylinder 8 is temporarily stopped and the “excavation work control” Control ”or Immediate transition to "non-drilling operation control" executed in the case of non-excavation work control) is to be executed.

  As a result, even if there is a transient pressure fluctuation in the hydraulic circuit or a temporary fluctuation of the detected data due to an operator shake or the like, the excavation work is determined based on the average value of the detected data that is always calculated. Therefore, the fluctuation of the temporary detection data can be eliminated, and a reliable and accurate determination can be performed. Moreover, “control for excavation work” suitable for excavation work is not executed only by estimating the start of the excavation work by the first determination criterion S1, and it is determined that the excavation operation is being performed by the second determination criterion S2. Since it will be executed if it can be done, it is possible to reliably avoid the execution of “excavation control” due to erroneous determination, and when the start of excavation work is estimated by the first determination criterion S1 In addition, by executing “excavation work preliminary control” which is a preliminary control of “excavation work control”, it is possible to smoothly shift to “excavation work control” without delay in response, It can greatly contribute to the improvement of workability and operability.

  Furthermore, in the present embodiment, the accumulator 18 that accumulates the oil energy of the oil discharged from the boom cylinder 8 when the boom 5 is lowered and the accumulated oil of the accumulator 18 when the boom 5 is raised are stored in the hydraulic circuit of the excavator 1. A reclaimed oil passage 41 that is joined to the oil discharged from the main pump 11 and supplied to the boom cylinder 8 is provided, and the work determination unit 56 determines that the work is excavation work and executes “control for excavation work”. In this case, the pressure accumulation in the accumulator 18 is stopped and the oil discharged from the head side oil chamber 8a of the boom cylinder 8 is caused to flow to the oil tank 14. As a result, in cases other than excavation work, the high pressure oil energy of the oil discharged from the head oil chamber 8a of the boom cylinder 8 can be recovered in the accumulator 18 without being wasted, and the boom 5 is lowered. At the time of excavation work in which a resisting force acts, the boom 5 can be smoothly lowered by flowing the pressure of the head side oil chamber 8a of the boom cylinder 8 to the oil tank 14 to make the pressure low. Thus, the presence or absence of pressure accumulation in the accumulator 18 can be appropriately performed based on the determination of the excavation work.

Of course, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the presence or absence of pressure accumulation in the accumulator is controlled based on the determination of the excavation work. Further, it can be configured to control whether or not the accumulated oil in the accumulator is reused based on the determination of various specific operations. Further, the regeneration circuit for reusing the accumulator pressure oil is not limited to the regeneration oil path from the accumulator to the discharge line of the first main pump as in the above embodiment, for example, from the accumulator Various regeneration circuits such as a regeneration circuit formed directly to the hydraulic actuator or a regeneration circuit formed to supply the hydraulic actuator via the pressure increasing means for increasing the pressure accumulation oil of the accumulator are appropriately adopted. can do.
Furthermore, in the above-described embodiment, the excavation work is set as the specific work, and it is determined whether or not the excavation work is performed. As work, loading work, leveling work, crane work, or boom lowering or airframe lifting operation (lifting the front of the airframe by lowering the boom relative to the airframe while the bucket is grounded) Operation), or various operations performed by the construction machine, such as operations using a breaker or a lifting magnet device, can be appropriately set. Also, the specific work can be classified and set according to the load, such as a heavy load work or a light load work.
Further, in determining the specific work, in the present embodiment, the average value / integral value calculation unit 58 calculates the average value of the detection data, and the average value is used to obtain the work load. The average value / integrated value calculation unit 58 may calculate the integrated value of the detected data and use the integrated value to calculate the work load.
Furthermore, as a first and second determination criteria for determining a specific task, it is needless to say that determination criteria suitable for each specific task can be set as appropriate.
In the above embodiment, the first workload determined by the first determination criterion and the second workload determined by the second determination criterion are different workloads (in the above embodiment, the first workload). Pw1 is the fluctuation amount of the current work load with respect to the average value of the working load within the second predetermined time T2, and the second work load Pw2 is the average value of the work load within the third predetermined time T3). Depending on the work, the same work load or a predetermined time used for calculating the average value or the integral value may be different.
Furthermore, in the above embodiment, it is configured to control the presence or absence of pressure accumulation in the accumulator based on the determination of the excavation work, but the present invention is of course not limited to such control, Hydraulic control and engine output control based on specific work determination include engine speed control, engine-to-hydraulic pump supply torque control, hydraulic pump discharge control, and oil path switching control by opening and closing various valves. Various controls such as opening control of a control valve that performs oil supply / discharge control to the hydraulic actuator can be executed.
Further, in the above embodiment, a pressure sensor (stick head side pressure sensor) for detecting the pressure of the oil chamber of the hydraulic actuator is used as the load detecting means for detecting the load of the hydraulic actuator. However, the present invention is not limited to this. Without limitation, for example, a load detection unit can be used as appropriate according to the determined specific work, such as a sensor for detecting the discharge pressure of the hydraulic pump or a sensor for detecting the cylinder length of the hydraulic cylinder.

It is a side view of a hydraulic excavator. It is a hydraulic circuit diagram of a hydraulic excavator. It is a block diagram which shows the input / output of a control apparatus. It is a control block diagram which shows the control procedure of a work determination part. It is a flowchart figure which shows the control procedure of a work determination part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 8 Boom cylinder 9 Stick cylinder 18 Accumulator 34 Control apparatus 41 Reproduction | regeneration oil path 52 Operation detection means for sticks 54 Stick head side pressure sensor 56 Work determination part 57 Buffer 58 Average value / integral value calculation part

Claims (2)

  In a construction machine including a hydraulic actuator that operates based on operation of an operation tool to perform various works, a specific work performed by the construction machine is determined, and hydraulic control and engine output control suitable for the specific work are performed. In this work determination system, the work determination system includes a load detection unit that detects a load of the hydraulic actuator, an operation detection unit that detects an operation state of the operation tool, and detection data of the load detection unit and the operation detection unit. Is stored in a buffer, the average value or the integral value within a predetermined time of the detection data is always calculated, and the operation determination means for determining a specific operation based on the average value or the integral value of the detection data, As a criterion for determining the specific work in the work determination means, a first determination standard that can estimate the start of the specific work and the specific work are performed. Set the second criterion that can be determined to be determined, and if it meets the second criterion, it performs control for the specific task suitable for the specific task, while it conforms to the first criterion but the second criterion A work determination system in a construction machine that performs specific work preliminary control that is preliminary control of specific work control when the standard is not met.   An accumulator for accumulating the oil energy of the oil discharged from any hydraulic actuator provided in the construction machine in the hydraulic circuit of the construction machine, and the accumulated oil of the accumulator is supplied to the hydraulic actuator or another hydraulic actuator for reuse. And the work determination system controls pressure accumulation in the accumulator or reuse of pressure accumulation oil in the accumulator based on determination of specific work by the work determination means. Work determination system in Japan.

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