CN105544630B - Construction machine - Google Patents
Construction machine Download PDFInfo
- Publication number
- CN105544630B CN105544630B CN201510712772.2A CN201510712772A CN105544630B CN 105544630 B CN105544630 B CN 105544630B CN 201510712772 A CN201510712772 A CN 201510712772A CN 105544630 B CN105544630 B CN 105544630B
- Authority
- CN
- China
- Prior art keywords
- pressure
- main pump
- discharge amount
- grapple
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
The invention provides a construction machine, which prevents the action of a movable arm (4) from being passivated when a grab bucket (6) is closed and the movable arm (4) is lifted. A construction machine according to an embodiment of the present invention includes a grab opening/closing cylinder (10) that opens/closes a grab (6), a boom cylinder (7) that drives a boom (4), a main pump (14L) connected to the grab opening/closing cylinder (10), and a main pump (14R) connected to the boom cylinder (7). In the construction machine, when a combined operation of a closing operation of the grab (6) and a lifting operation of the boom (4) is performed, the discharge rate of the main pump (14R) is made larger than the discharge rate of the main pump (14L).
Description
Technical Field
The present application claims priority based on japanese patent application No. 2014-219590, which was applied on day 28/10/2014. The entire contents of this Japanese application are incorporated by reference into this specification.
The present invention relates to a construction machine equipped with a grab bucket.
Background
A hydraulic control circuit of a hydraulic construction machine including a crushing cylinder that drives a crushing device is known (see patent document 1).
When the crushing cylinder and the arm cylinder connected in parallel to the hydraulic pump are combined to perform a combined operation, the hydraulic control circuit decreases the discharge amount corresponding to the crushing operation amount when the discharge pressure of the hydraulic pump becomes equal to or higher than a predetermined value. Further, a sharp increase in the speed of the arm due to the crushing cylinder reaching the stroke end is prevented.
Patent document 1: japanese patent application laid-open No. 2010-31978
However, the above-described hydraulic control circuit does not consider a case where the pressure of the working oil (arm load pressure) required to drive the arm cylinder is greater than the relief pressure of the line relief valve of the associated crushing cylinder (crushing cylinder relief pressure). Therefore, when the crushing cylinder and the arm cylinder are combined, if the arm load pressure is higher than the crushing cylinder safety pressure, a part of the hydraulic oil to be flowed into the arm cylinder flows out of the line safety valve, and the arm cylinder is deactivated.
Disclosure of Invention
In view of the above problems, the present invention is intended to provide a construction machine that prevents the operation body from being inactivated when performing a combined operation of a grapple closing operation and an operation body constituting an attachment.
A construction machine according to an embodiment of the present invention includes a1 st hydraulic actuator that opens and closes a grapple, a2 nd hydraulic actuator that drives an operation body that constitutes an attachment, a1 st pump connected to the 1 st hydraulic actuator, and a2 nd pump connected to the 2 nd hydraulic actuator, wherein when a combined operation of the grapple closing operation and the operation body operation is performed, a discharge rate of the 2 nd pump is made larger than a discharge rate of the 1 st pump.
Effects of the invention
According to the above-described structure, there is provided a construction machine that prevents the operation body from being inactivated when performing a combined operation of a grapple closing operation and an operation body operation constituting an attachment.
Drawings
Fig. 1 is a side view of a construction machine according to an embodiment of the present invention.
Fig. 2 is a block diagram showing a configuration example of a drive system of the construction machine of fig. 1.
Fig. 3 is a schematic diagram showing a configuration example of a hydraulic circuit mounted on the construction machine of fig. 1.
Fig. 4 is a flowchart showing an example of the discharge amount adjustment process.
Fig. 5 is a diagram showing an example of a discharge pressure-discharge amount map.
Fig. 6 is a diagram of a state of the hydraulic circuit of fig. 3 when discharge amount adjustment is started.
Fig. 7 is a diagram of a state of the hydraulic circuit of fig. 3 when discharge amount adjustment is started.
Fig. 8 is a diagram showing a state of the hydraulic circuit of fig. 3 when the discharge amount adjustment is stopped.
Fig. 9 is a diagram showing the time course of various physical quantities when the discharge amount is adjusted.
In the figure: 1-lower traveling body, 1A, 1B-hydraulic motor for traveling, 2-slewing mechanism, 2A-hydraulic motor for slewing, 3-upper slewing body, 4-boom, 5-arm, 6-grab, 7-boom cylinder, 8-arm cylinder, 9-bucket cylinder, 10-grab opening/closing cylinder, 11-engine, 13L, 13R-regulator, 14L, 14R-main pump, 15-pilot pump, 17-control valve, 20L, 20R-negative control throttle valve, 21L, 21R-center bypass oil passage, 22L, 22R-parallel oil passage, 23L, 23R-return oil passage, 26-operation device, 29-pressure sensor, 30-controller, 50-safety valve, 51, 2A-hydraulic motor for slewing, 3-upper slewing body, 14-boom, 5-arm, 6-grab, 14-main pump, 15-pilot pump, 17-control valve, 20L, 20R-negative control throttle, 52-load check valve, 54-combined flow path, 171L-175L and 171R-175R-control valves, S1L, S1R, S2L, S2R, S3, S4 and S5-pressure sensors and T-working oil tank.
Detailed Description
First, a construction machine according to an embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a side view of the construction machine. An upper revolving body 3 is mounted on a lower traveling body 1 of the construction machine shown in fig. 1 via a revolving mechanism 2. An attachment is mounted on the upper slewing body 3. The attachment is composed of a boom 4, an arm 5, and a grab 6 as a construction body. Specifically, the boom 4 is attached to the upper slewing body 3. An arm 5 is attached to the front end of the boom 4, and a grab bucket 6 as a terminal attachment is attached to the front end of the arm 5. The boom 4 is rotated by a boom cylinder 7, and the arm 5 is rotated by an arm cylinder 8. The grapple 6 is rotated by a boom cylinder (grapple tilt cylinder) 9, and the grapple opening/closing cylinder 10 opens and closes the hook 6 a. The bucket cylinder 9 is a general hydraulic cylinder for turning a bucket when the bucket is used in place of the grapple 6, and in the present embodiment, is used for turning (tilting) the grapple 6. The upper slewing body 3 is provided with a cab and an engine 11 and the like are mounted thereon. Fig. 1 also shows a state a1 of the attachment when the construction object is gripped by the grapple 6, and a state a2 of the attachment when the construction object is gripped by the grapple 6 and then suspended.
Fig. 2 is a block diagram showing a configuration example of a drive system of the construction machine of fig. 1, and a mechanical power system, a high-pressure hydraulic line, a pilot line, and an electric control system are shown by a double line, a solid line, a broken line, and a one-dot chain line, respectively.
The drive system of the construction machine mainly includes an engine 11, a regulator 13, a main pump 14, a pilot pump 15, a control valve 17, an operation device 26, a pressure sensor 29, and a controller 30.
The engine 11 is a drive source of the construction machine. In the present embodiment, the engine is a diesel engine as an internal combustion engine that operates to maintain a predetermined number of revolutions. An output shaft of the engine 11 is connected to input shafts of the main pump 14 and the pilot pump 15.
The main pump 14 supplies working oil to the control valve 17 via a high-pressure hydraulic line. In the present embodiment, the main pump 14 is a swash plate type variable displacement hydraulic pump.
The pilot pump 15 supplies the operating device 26 with hydraulic oil via a pilot line. In the present embodiment, the pilot pump 15 is a fixed displacement hydraulic pump.
The control valve 17 is a hydraulic control device that controls a hydraulic system in the construction machine. In the present embodiment, the control valve 17 selectively supplies the hydraulic oil discharged from the main pump 14 to 1 or more of the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the grapple opening/closing cylinder 10, the left traveling hydraulic motor 1A, the right traveling hydraulic motor 1B, and the turning hydraulic motor 2A. Hereinafter, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the bucket opening/closing cylinder 10, the left traveling hydraulic motor 1A, the right traveling hydraulic motor 1B, and the turning hydraulic motor 2A are collectively referred to as "hydraulic actuators".
The operating device 26 is a device for an operator to operate the hydraulic actuator. In the present embodiment, the operation device 26 supplies the hydraulic oil discharged from the pilot pump 15 to the pilot port of the control valve in the control valve 17. Specifically, the operating device 26 supplies the hydraulic oil discharged from the pilot pump 15 to the pilot ports of the control valves corresponding to the respective hydraulic actuators. The pressure (pilot pressure) of the hydraulic oil supplied to each pilot port is based on the operation direction and the operation amount of an operation lever or a pedal (not shown) of the operation device 26 corresponding to each hydraulic actuator.
The pressure sensor 29 is an example of an operation content detecting unit for detecting the operation content of the operation device 26. In the present embodiment, the pressure sensor 29 detects the operation direction and the operation amount of the operation device 26 corresponding to each of the hydraulic actuators in the form of pressure, and outputs the detected values to the controller 30. The operation content of the operation device 26 may be detected by a sensor other than a pressure sensor, such as an inclination sensor that detects the inclination of various operation levers. Specifically, the pressure sensors 29 are attached to the respective operation devices 26 such as a left-side travel operation lever, a right-side travel operation lever, an arm operation lever, a swing operation lever, a boom operation lever, a bucket tilt operation lever, and a bucket opening/closing pedal.
The controller 30 is a control device for controlling the construction machine. In the present embodiment, the controller 30 is constituted by a computer having a CPU, RAM, ROM, and the like. The controller 30 reads programs corresponding to the various functional elements from the ROM, uploads the programs to the RAM, and the CPU executes processes corresponding to the various functional elements.
The controller 30 detects the operation content (for example, the presence or absence of a lever operation, a lever operation direction, a lever operation amount, and the like) of each of the operation devices 26 based on the output of the pressure sensor 29.
Next, a configuration example of a hydraulic circuit mounted on the construction machine of fig. 1 will be described with reference to fig. 3. Fig. 3 is a diagram showing a configuration example of a hydraulic circuit mounted on the construction machine of fig. 1. Fig. 3 is the same as fig. 2, and shows the high-pressure hydraulic line, the pilot line, and the electric control system by solid lines, broken lines, and alternate long and short dash lines, respectively.
The main pumps 14L, 14R are variable displacement hydraulic pumps driven by the engine 11, and correspond to the main pump 14 of fig. 2. In the present embodiment, the main pump 14L circulates the hydraulic oil to the hydraulic oil tank T through the center bypass oil passage 21L passing through each of the control valves 171L to 175L constituting the control valve 17. Main pump 14L can supply hydraulic oil to control valves 172L to 175L through parallel oil passage 22L extending in parallel with center bypass oil passage 21L. Similarly, the main pump 14R circulates the hydraulic oil to the hydraulic oil tank T through the center bypass oil passage 21R passing through each of the control valves 171R to 175R constituting the control valve 17. The main pump 14R can supply the hydraulic oil to the control valves 172R to 175R through a parallel oil passage 22R extending in parallel with the center bypass oil passage 21R. Hereinafter, main pump 14L and main pump 14R may be referred to collectively as "main pump 14". The same applies to other constituent elements including a pair of left and right.
The control valve 171L is a Spool valve (Spool valve) that switches the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14L to the left travel hydraulic motor 1A when a left travel operation lever (not shown) is operated.
The control valve 171R is a spool valve as a traveling straight-ahead valve. In the present embodiment, the travel linear valve 171R is a four-way two-position linear axis valve having the 1 st valve position and the 2 nd valve position. Specifically, the 1 st valve position includes a flow path that connects main pump 14L and parallel oil path 22L, and a flow path that connects main pump 14R and control valve 172R. The 2 nd valve position includes a flow path that connects main pump 14R and parallel oil path 22L, and a flow path that connects main pump 14L and control valve 172R.
The control valve 172L is a spool valve that switches the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14L to the grapple open/close cylinder 10 when a grapple open/close pedal (not shown) is operated.
The control valve 172R is a spool valve that switches the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14 to the right travel hydraulic motor 1B when a right travel operation lever (not shown) is operated.
The control valve 173L is a spool valve that switches the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14 to the hydraulic motor for turning 2A when a turning operation lever (not shown) is operated.
The control valve 173R is a spool valve that switches the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14R to the bucket cylinder 9 when a bucket tilt lever (not shown) is operated.
The control valves 174L and 174R are spool valves that switch the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14 to the boom cylinder 7 when a boom operation lever (not shown) is operated. When the boom operation lever is operated in the boom raising direction by a predetermined lever operation amount or more, the control valve 174L additionally supplies the hydraulic oil to the boom cylinder 7.
The control valves 175L and 175R are spool valves that switch the flow of hydraulic oil in order to supply the hydraulic oil discharged from the main pump 14 to the arm cylinder 8 when an arm control lever (not shown) is operated. When the arm operation lever is operated by the predetermined lever operation amount or more, the control valve 175R additionally supplies the hydraulic oil to the arm cylinder 8.
The hydraulic oil that has flowed out of each of the left travel hydraulic motor 1A, the grapple opening/closing cylinder 10, the swing hydraulic motor 2A, and the arm cylinder 8 is discharged to the hydraulic oil tank T through the return oil passage 23L. Similarly, the hydraulic oil that has flowed out of each of the right traveling hydraulic motor 1B, the bucket cylinder 9, and the boom cylinder 7 is discharged to the hydraulic oil tank T through the return oil passage 23R. Part of the hydraulic oil flowing out of the arm cylinder 8 may be discharged to the hydraulic oil tank T through the return oil passage 23R.
The center bypass oil passages 21L, 21R include negative control throttles 20L, 20R between the control valves 175L, 175R located at the most downstream positions and the hydraulic oil tank T, respectively. In addition, the negative control is hereinafter simply referred to as "negative control". The negative control throttle valves 20L, 20R restrict the flow of the hydraulic oil discharged from the main pumps 14L, 14R, and a negative control pressure is generated upstream of the negative control throttle valves 20L, 20R. The controller 30 performs negative control using the negative control pressure. Specifically, the discharge rates of the main pumps 14L, 14R are increased as the negative control pressure generated by the negative control throttle valves 20L, 20R is lower. When the negative control pressure generated by the negative control throttle valves 20L and 20R exceeds a predetermined pressure, the discharge rates of the main pumps 14L and 14R are reduced to a predetermined lower limit value.
The relief valve 50 is a valve that controls the pressure of the bottom oil chamber of the grapple opening/closing cylinder 10 to a predetermined closing relief pressure or less.
The load check valve 51 is a valve that prevents the hydraulic oil in the grapple opening/closing cylinder 10 from flowing backward to the parallel oil passage 22L.
The pressure sensors S1L, S1R detect the negative control pressure generated upstream of the negative control throttle valves 20L, 20R, and output the detected value to the controller 30 as an electric negative control pressure signal.
The pressure sensors S2L, S2R detect the discharge pressures of the main pumps 14L, 14R, and output the detected values to the controller 30 as electric discharge pressure signals.
The pressure sensor S3 detects the pressure of the bottom oil chamber of the grapple opening/closing cylinder 10 (hereinafter referred to as "grapple bottom pressure"), and outputs the detected value to the controller 30 as an electric grapple bottom pressure signal.
The pressure sensor S4 is one of the pressure sensors 29, detects a pilot pressure (hereinafter referred to as a "grapple close pilot pressure") acting on a right-side (grapple close side) pilot port of the control valve 172L, and outputs the detected value to the controller 30 as an electric grapple close pilot pressure signal.
The pressure sensor S5 is one of the pressure sensors 29, detects a pilot pressure (hereinafter referred to as a "boom-up pilot pressure") acting on a left-side (boom-up side) pilot port of the control valve 174L and a right-side (boom-up side) pilot port of the control valve 174R, and outputs the detected value to the controller 30 as an electric boom-up pilot pressure signal.
The controller 30 receives outputs from the pressure sensors 29, S1L, S1R, S2L, S2R, S3, S4, S5, and the like, and causes the CPU to execute a program for adjusting the discharge rates of the main pumps 14L, 14R, respectively.
When the hydraulic actuator related to the main pump 14L (e.g., the grapple open/close cylinder 10) and the hydraulic actuator related to the main pump 14R (e.g., the boom cylinder 7) are continuously operated by the full (full) operation lever/full (full) pedal (e.g., an operation amount of 80% or more when the neutral state of the operation lever/pedal is 0% and the maximum operation state is 100%), the controller 30 makes the discharge amount L1 of the main pump 14L and the discharge amount L2 of the main pump 14R the same. Hereinafter, this method will be referred to as "discharge rate synchronization method".
Next, an example of a process (hereinafter referred to as "discharge amount adjustment process") in which the controller 30 adjusts the discharge amount of the main pump 14 when a combined operation of the grapple 6 closing operation and the operating body operation is performed will be described with reference to fig. 4. Fig. 4 is a flowchart showing an example of the flow of the discharge amount adjustment process, and the controller 30 repeatedly executes the discharge amount adjustment process at a predetermined control cycle.
First, the controller 30 determines whether or not the discharge amount is being adjusted (step ST 1). In the present embodiment, the controller 30 refers to the flag value during adjustment stored in the RAM or the like, and determines whether or not the discharge amount of the main pump 14 is being adjusted. The adjustment flag has an initial value "0" indicating "not being adjusted", and can be switched to a value "1" indicating "being adjusted".
If it is determined that the discharge amount adjustment is not being performed (NO at step ST1), the controller 30 determines whether or not a discharge amount adjustment start condition is satisfied (step ST 2). In this embodiment, the controller 30 sets the starting condition that the grapple cylinder bottom pressure is higher than the predetermined pressure TH1 and the grapple closing pilot pressure is higher than the predetermined pressure TH 2. The controller 30 may set the start condition to a state in which a pilot pressure (hereinafter, referred to as a "swing pilot pressure") acting on a pilot port of the control valve 173L is lower than a predetermined pressure TH3, that is, a state in which no swing operation is performed. Further, the controller 30 may set the start condition to a state in which a pilot pressure (hereinafter, referred to as "arm closing pilot pressure") acting on a left-side (arm closing-side) pilot port of the control valve 175L is lower than the predetermined pressure TH4, that is, an arm closing operation is not performed. The predetermined pressures TH1 to TH4 are stored in advance in ROM or the like. The predetermined pressure TH1 is set to a pressure slightly lower than the closing relief pressure.
When it is determined that the start condition is not satisfied (NO at step ST2), the controller 30 ends the present discharge rate adjustment process without starting the discharge rate adjustment.
When it is determined that the start condition is satisfied (YES at step ST2), the controller 30 starts the discharge amount adjustment (step ST 3). In this embodiment, the controller 30 switches the adjustment flag to a value of "1". In addition, the controller 30 adjusts the discharge amount L1 of the main pump 14L in accordance with the discharge pressure P2 of the main pump 14R. Specifically, the controller 30 refers to a discharge pressure-discharge amount map stored in advance in a ROM or the like, and derives a discharge amount L1 corresponding to the discharge pressure P2.
Fig. 5 is a diagram showing an example of a discharge pressure-discharge amount map, in which the horizontal axis corresponds to the discharge pressure P2 of the main pump 14R and the vertical axis corresponds to the discharge amount L1 of the main pump 14L. Also, fig. 5 shows the following relationship: when the discharge pressure P2 is equal to or less than the value P2L, the allowable maximum value of the discharge amount L1 becomes the upper limit value Lmax, and when the discharge pressure P2 is greater than the value P2L and smaller than the value P2H, the allowable maximum value of the discharge amount L1 decreases as the discharge pressure P2 increases, and when the discharge pressure P2 is equal to or greater than the value P2H, the allowable maximum value of the discharge amount L1 becomes the lower limit value Lmin.
Also, the controller 30 avoids the total absorption horsepower (or the total absorption torque) of the main pump 14 from exceeding the output horsepower of the engine 11 by the total horsepower control. The total absorption horsepower of the main pump 14 is the sum of the absorption horsepower (or absorption torque) of the main pump 14L expressed by the product of the discharge pressure P1 and the discharge amount L1 of the main pump 14L and the absorption horsepower (or absorption torque) of the main pump 14R expressed by the product of the discharge pressure P2 and the discharge amount L2 of the main pump 14R. Therefore, as long as the discharge amount L1 of the main pump 14L is determined, the controller 30 can uniquely determine the allowable maximum value of the discharge amount L2 of the main pump 14R. Specifically, the smaller the allowable maximum value of the discharge amount L1 is, the larger the allowable maximum value of the discharge amount L2 can be.
Fig. 6 and 7 are diagrams showing a state of the hydraulic circuit of fig. 3 when discharge amount adjustment is started, in which arrows of thick solid lines indicate a flow direction of the hydraulic oil, and the thicker the thick solid lines, the larger the flow rate of the hydraulic oil.
Specifically, fig. 6 shows a state in which the attachment is in a state a1 of fig. 1, the closing operation of the grapple 6 is performed alone, and the grapple 6 grips the construction object (after the movement of the hook 6a in the closing direction is stopped). At this time, since the hydraulic oil discharged from the main pump 14R is discharged to the hydraulic oil tank T through the center bypass oil passage 21R, the discharge pressure P2 of the main pump 14R is in a state smaller than the value P2L (see fig. 5). Therefore, the controller 30 refers to the discharge pressure-discharge amount map of fig. 5, and sets the allowable maximum value of the discharge amount L1 of the main pump 14L to the upper limit value Lmax. As a result, the hydraulic oil discharged from the main pump 14L is discharged to the hydraulic oil tank T through the relief valve 50 while the pressure of the hydraulic oil (see the thick broken line portion in fig. 6) in the oil passage connected to the cylinder bottom side of the grapple open/close cylinder 10 and in the parallel oil passage 22L is set to be equal to or higher than the closing relief pressure. Further, until the grapple 6 grips the construction object, that is, until the movement of the hook 6a in the closing direction is stopped, the grapple cylinder bottom pressure does not reach the predetermined pressure TH 1. This is because the oil chamber at the bottom of the bucket opening/closing cylinder 10 becomes large when the hook 6a moves in the closing direction, and receives the hydraulic oil discharged from the main pump 14L. The grapple cylinder bottom pressure increases as the grapple 6 compresses the construction target, that is, as the movement of the hook 6a in the closing direction becomes slower. When the grapple bottom pressure reaches the predetermined closing pressure TH1, the inflow of the hydraulic oil into the bottom oil chamber is stopped, and the movement of the hook 6a in the closing direction is stopped. Therefore, the state in which the grapple cylinder bottom pressure is greater than the predetermined pressure TH1 indicates the state after the grapple 6 finishes gripping the construction object.
Fig. 7 shows a state of the hydraulic circuit when a combined operation of the closing operation of the grapple 6 and the lifting operation of the boom 4 is performed. Specifically, the state of the hydraulic circuit when the attachment is at state a2 in fig. 1 is shown. At this time, since the hydraulic oil discharged from the main pump 14R flows into the cylinder bottom oil chamber of the boom cylinder 7, the discharge pressure P2 of the main pump 14R is greater than the value P2L (see fig. 5). Therefore, the controller 30 refers to the discharge pressure-discharge amount map of fig. 5 to set the allowable maximum value of the discharge amount L1 of the main pump 14L to be smaller than the upper limit value Lmax. At this time, although the discharge amount L1 is lower than when the grapple 6 is closed alone, the hydraulic oil discharged from the main pump 14L is discharged to the hydraulic oil tank T through the relief valve 50 while the pressure of the hydraulic oil (see the broken line portion in fig. 7) in the oil passage connected to the cylinder bottom side of the grapple opening/closing cylinder 10 and in the parallel oil passage 22L is equal to or higher than the closing relief pressure, as in the case when the grapple 6 is closed alone. Further, the discharge pressure P2 of the main pump 14R is greater than the discharge pressure P1 of the main pump 14L, but the hydraulic oil discharged by the main pump 14R does not flow into the parallel oil passage 22L. This is because the flow toward the parallel oil passage 22L is blocked by the load check valve 52.
In this way, even when the closing operation of the grapple 6 and the raising operation of the boom 4 are continued with the full lever/full pedal, the controller 30 controls the discharge amount L1 of the main pump 14L and the discharge amount L2 of the main pump 14R, respectively. Specifically, the total suction horsepower of the main pump 14 is made smaller than the output horsepower of the engine 11, and the discharge amount L1 of the main pump 14L is made smaller as the discharge pressure P2 of the main pump 14R is higher. As a result, the controller 30 can increase the discharge amount L2 and increase the raising speed of the boom 4, as compared to when the discharge amount L1 and the discharge amount L2 are the same. Further, the controller 30 can reduce the amount of hydraulic oil discharged from the relief valve 50 because the discharge amount L1 of the main pump 14L is reduced.
On the other hand, if it is determined in step ST1 that the discharge amount adjustment is being performed (YES in step ST1), the controller 30 determines whether or not a stop condition for the discharge amount adjustment is satisfied (step ST 4). In the present embodiment, the controller 30 sets the discharge pressure P1, the grapple cylinder bottom pressure, or the grapple closing pilot pressure to be lower than the predetermined pressure TH5 (< TH1), or the grapple closing pilot pressure to be lower than the predetermined pressure TH6 (< TH2) as the stop condition. The controller 30 may set the stop condition to a slewing operation in which the slewing pilot pressure is higher than the predetermined pressure TH7 (> TH 3). Further, the controller 30 may set the arm closing operation to the stop condition such that the arm closing pilot pressure is higher than the predetermined pressure TH8 (> TH 4). The predetermined pressures TH5 to TH8 are stored in advance in ROM or the like. The predetermined pressures TH5 and TH6 are set to values smaller than the predetermined pressures TH1 and TH2, respectively, and the predetermined pressures TH7 and TH8 are set to values larger than the predetermined pressures TH3 and TH4, respectively. This is to prevent the start and stop of discharge amount adjustment from being frequently repeated because the start condition and the stop condition are alternately satisfied.
When it is determined that the stop condition is satisfied (YES at step ST4), the controller 30 stops the discharge amount adjustment (step ST 5). In this embodiment, the controller 30 switches the adjustment middle flag to "0". On the basis of this, the controller 30 controls the discharge amounts of the main pumps 14L, 14R in accordance with the existing negative control and total horsepower control.
Fig. 8 is a diagram showing an example of a state of the hydraulic circuit of fig. 3 when the discharge amount adjustment is stopped, and in the diagram, thick solid arrows indicate a flow direction of the hydraulic oil. Fig. 8 shows a state of the hydraulic circuit when a combined operation of the closing operation of the grapple 6 and the raising operation of the boom 4 is performed. Specifically, the hydraulic circuit state of the attachment at state a2 in fig. 1 is shown. At this time, since the hydraulic oil discharged from the main pump 14R flows into the cylinder bottom oil chamber of the boom cylinder 7, the discharge pressure P2 of the main pump 14R is greater than the value P2L (see fig. 5). On the other hand, when the turning radius of the attachment is smaller than the state a1 (see fig. 1), the discharge pressure P2 is also smaller than the state a1 (see fig. 1), that is, is smaller than in the hydraulic circuit state shown in fig. 7, and is in a state of being smaller than the discharge pressure P1 and the closed relief pressure. Therefore, the hydraulic oil discharged from the main pump 14L merges with the hydraulic oil discharged from the main pump 14R through the parallel oil passage 22L and the control valve 174L, and flows into the bottom oil chamber of the boom cylinder 7. As a result, the discharge pressure P1 becomes equal to the discharge pressure P2. Since the grapple opening/closing cylinder 10 and the boom cylinder 7 are continuously operated by the full-operation lever and the full-pedal, the discharge amount L1 of the main pump 14L and the discharge amount L2 of the main pump 14R are controlled to be the same value. In this case, the pressure of the hydraulic oil (see the broken line portion in fig. 8) in the oil passage connected to the cylinder bottom side of the grapple opening/closing cylinder 10 is also maintained in the vicinity of the closing relief pressure. This is because the flow to the parallel oil passage 22L is blocked by the load check valve 51.
In this way, when the discharge amount adjustment is performed, the controller 30 stops the discharge amount adjustment when the stop condition is satisfied. For example, when the discharge pressure P2 of the main pump 14R is lower than the predetermined pressure TH5, and as a result, the discharge amount adjustment is stopped when the discharge pressure P1 of the main pump 14L is lower than the predetermined pressure TH 5. Therefore, when the hydraulic oil from the main pump 14L and the hydraulic oil from the main pump 14R merge and flow into the boom cylinder 7, it is possible to prevent the discharge amount L1 from being excessively restricted and the raising speed of the boom 4 from becoming sluggish. That is, when the pressure of the bottom oil chamber of the boom cylinder 7 is lower than the closing relief pressure, the discharge amount L1 of the main pump 14L is increased, and the hydraulic oil from the main pump 14L and the hydraulic oil from the main pump 14R can be merged and flow into the boom cylinder 7.
The controller 30 stops the discharge amount adjustment when the grapple cylinder bottom pressure is less than the predetermined pressure TH 5. Therefore, even when the construction object gripped by the grapple 6 is scattered, sufficient hydraulic oil is quickly supplied to the cylinder bottom oil chamber of the grapple opening/closing cylinder 10, whereby further gripping of the grapple 6 can be quickly achieved.
Next, the time transition of various physical quantities when the discharge amount is adjusted will be described with reference to fig. 9. Fig. 9 is a diagram showing a time course of various physical quantities when the discharge amount is adjusted. Specifically, fig. 9 shows the ON/OFF state of the grapple closing operation, the ON/OFF state of the boom raising operation, the discharge amount L1 of the main pump 14L, the discharge amount L2 of the main pump 14R, and the time passage of the boom flow rate. The ON state of the grapple closing operation is a state in which the grapple opening/closing cylinder 10 is operated with the full pedal, and the ON state of the boom raising operation is a state in which the boom cylinder 7 is operated with the full lever. The boom flow rate is a flow rate of the hydraulic oil flowing into the bottom oil chamber of the boom cylinder 7. Note that, in fig. 9, a solid line indicates a time passage when the discharge amount adjustment is performed, and a broken line indicates a time passage when the discharge amount adjustment is not performed as a comparison target.
As shown in fig. 9, when the gripper closing operation is turned ON at time t1, the controller 30 starts the discharge rate adjustment. Specifically, when the controller 30 detects that the grapple bottom pressure, which is the output of the pressure sensor S3, is greater than the predetermined pressure TH1 and the grapple closing pilot pressure, which is the output of the pressure sensor S4, is greater than the predetermined pressure TH2, it is determined that the start condition is satisfied and the discharge amount adjustment is started.
As a result, the discharge amount L1 of the main pump 14L increases from the lower limit value Lmin to the upper limit value Lmax, which is used when none of the hydraulic actuators is operated. Specifically, the controller 30 refers to a discharge pressure-discharge amount map as shown in fig. 5, derives the upper limit value Lmax from the discharge pressure P2 of the main pump 14R, and increases the discharge amount L1 to the upper limit value Lmax. At this time, the discharge pressure P2 of the main pump 14R is smaller than the value P2L.
Thereafter, at time t2, when the boom raising operation is turned ON, the discharge amount L1 of the main pump 14L is decreased to the lower limit value Lmin. Specifically, the controller 30 refers to a discharge pressure/discharge amount map as shown in fig. 5, derives the lower limit value Lmin from the discharge pressure P2 of the main pump 14R, and lowers the discharge amount L1 to the lower limit value Lmin. At this time, the discharge pressure P2 of the main pump 14R is equal to or greater than the value P2H.
On the other hand, the discharge amount L2 of the main pump 14R increases from the lower limit value Lmin employed when none of the associated hydraulic actuators is operating to the flow amount Lm. Specifically, the controller 30 derives the discharge amount Lm so that the total suction horsepower of the main pump 14 does not exceed the output horsepower of the engine 11 under the total horsepower control, and increases the discharge amount L2 to the flow amount Lm. As a result, the boom flow rate increases to the flow rate Lm. The total suction horsepower T is represented by T ═ k (coefficient) x (P1 × L1+ P2 × L2). When the total absorption horsepower T is kept constant, the discharge amount L2 (the flow rate Lm) increases as the discharge amount L1 decreases.
In this way, when the combined operation of the closing operation of the grapple 6 and the raising operation of the boom 4 is performed, the controller 30 makes the discharge amount L2 of the main pump 14R larger than the discharge amount L1 of the main pump 14L. Therefore, the operation of raising the boom 4 can be prevented from becoming dull.
At time t2, when discharge rate adjustment is not performed, the discharge rates L1 and L2 of the main pumps 14L and 14R are both set to the flow rate Lp under the total horsepower control. Specifically, the discharge amount L1 of the main pump 14L is decreased to a flow rate Lp larger than the lower limit value Lmin, and the discharge amount L2 of the main pump 14R is increased to a flow rate Lp smaller than the flow rate Lm. Therefore, the boom flow rate is limited to a flow rate Lp smaller than the flow rate Lm at the time of performing discharge rate adjustment. As a result, the raising speed of the boom 4 becomes slower than when the discharge amount adjustment is performed.
Specifically, in the discharge rate synchronization method, that is, in the method in which the discharge rate L1 and the discharge rate L2 cannot be controlled separately when the full-operation lever/full-pedal closing operation of the grapple 6 and the boom 4 raising operation are continued, when the cylinder bottom oil chamber pressure of the boom cylinder 7 is higher than the closing relief pressure, the hydraulic oil discharged from the main pump 14L cannot be caused to flow into the cylinder bottom oil chamber of the boom cylinder 7 via the control valve 174L. This is because most of the working oil is discharged to the working oil tank T through the relief valve 50. At this time, increasing the discharge amount L2 means increasing the discharge amount L1, that is, increasing the flow rate of the working oil wastefully discharged by the relief valve 50. Further, since the suction horsepower of the main pump 14L is also unnecessarily increased by increasing the discharge amount L1, the increase width of the suction horsepower of the main pump 14R under the total horsepower control, that is, the increase width of the discharge amount L2 is also limited.
On the other hand, when the pressure of the bottom oil chamber of the boom cylinder 7 is higher than the closing relief pressure, the controller 30 that performs discharge amount adjustment drives the boom cylinder 7 only by the hydraulic oil discharged from the main pump 14R. That is, the discharge amount L1 of the main pump 14L is reduced by not unnecessarily merging the hydraulic oil discharged from the main pump 14L, and the discharge amount L2 of the main pump 14R can be greatly increased under the total horsepower control. As a result, the boom 4 can be prevented from being lifted up.
Further, when a combined operation of a closing operation of the grapple 6 and a raising operation of the boom 4 is performed, the controller 30 lowers the discharge rate of the main pump 14L as compared with a case where the closing operation of the grapple 6 is performed alone. Therefore, the suction horsepower that can be consumed by the main pump 14R can be increased by an amount corresponding to a reduction in the suction horsepower of the main pump 14L, and the discharge amount L2 of the main pump 14R can be further increased.
Further, the controller 30 changes the discharge rate of the main pump 14L in accordance with the difference between the closing relief pressure and the grapple bottom pressure when performing the combined operation of the closing operation of the grapple 6 and the lifting operation of the boom 4. Specifically, when the difference becomes large during the discharge rate adjustment, that is, when the grapple bottom pressure becomes lower than the predetermined pressure TH5, the discharge rate adjustment is stopped, and the discharge rates of the main pumps 14L and 14R are controlled by the conventional negative control and total horsepower control. Therefore, even when the construction object gripped by the grapple 6 is scattered, the grapple 6 can be gripped more quickly by quickly supplying sufficient hydraulic oil to the cylinder bottom oil chamber of the grapple opening/closing cylinder 10.
When a combined operation of the closing operation of the grapple 6 and the raising operation of the boom 4 is performed, the controller 30 changes the discharge amount L1 of the main pump 14L in accordance with the discharge pressure P2 of the main pump 14R. For example, the discharge amount L1 of the main pump 14L is reduced as the discharge pressure P2 of the main pump 14R is higher. As a result, when the pressure of the bottom oil chamber of the boom cylinder 7 is higher than the closing relief pressure, the discharge amount L1 of the main pump 14L is decreased, whereby the discharge amount L2 of the main pump 14R can be increased under the total horsepower control.
The hydraulic circuit of fig. 3 includes a merging passage 54 through which the hydraulic oil discharged from the main pump 14L and the hydraulic oil discharged from the main pump 14R merge when the boom 4 is lifted. A load check valve 52 that blocks the flow from the main pump 14R to the main pump 14L is disposed in the combined flow path 54. Therefore, when the pressure of the bottom oil chamber of the boom cylinder 7 is higher than the closing relief pressure, the boom cylinder 7 can be driven only by the hydraulic oil discharged from the main pump 14R, and the closing operation of the grapple 6 can be continued in a state where the discharge amount L1 of the main pump 14L is reduced.
While the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various modifications and substitutions can be made to the above embodiments without departing from the scope of the present invention.
For example, in the above-described embodiment, the discharge amount adjustment is performed when a combined operation of the closing operation of the grapple 6 and the lifting operation of the boom 4 is performed. However, the present invention is not limited to this configuration. For example, the discharge amount adjustment may be performed when performing a composite operation of the closing operation of the grapple 6 and the opening operation of the arm 5, or the like, other composite operations including the closing operation of the grapple 6.
In the above-described embodiment, the discharge amount adjustment is performed by the construction machine having the grapple opening/closing cylinder 10. However, the present invention is not limited to this configuration. For example, the discharge amount adjustment may be performed in a construction machine having another hydraulic actuator that drives the hydraulic oil while releasing the pressure of the hydraulic oil.
Claims (5)
1. A construction machine has:
a1 st hydraulic actuator for opening and closing the grab bucket;
a2 nd hydraulic actuator for driving a boom or an arm constituting an attachment having the grapple at a tip end thereof;
the 1 st pump is connected with the 1 st hydraulic driver; and
a2 nd pump connected to the 2 nd hydraulic driver,
wherein, when a combined operation of the closing operation of the grapple and the operation in the boom raising direction or the arm opening direction is performed, the discharge amount of the 2 nd pump is made larger than the discharge amount of the 1 st pump.
2. The construction machine according to claim 1,
when a combined operation of the closing operation of the grapple and the operation of the operation body is performed, the discharge amount of the 1 st pump is reduced as compared with when the closing operation of the grapple alone is performed.
3. The construction machine according to claim 1 or 2,
the construction machine has a relief valve that, when the closing operation of the grab is performed, causes at least a part of the working oil directed toward the 1 st hydraulic actuator to flow out,
when a combined operation of the closing operation of the grapple and the operation of the operation body is performed, the discharge amount of the 1 st pump is changed in accordance with a difference between a relief pressure of the relief valve and a pressure of the hydraulic oil flowing into the 1 st hydraulic actuator which is equal to or lower than the relief pressure.
4. The construction machine according to claim 1 or 2,
when a combined operation of the closing operation of the grab and the operation of the operation body is performed, the discharge amount of the 1 st pump is changed according to the discharge pressure of the 2 nd pump.
5. The construction machine according to claim 1 or 2,
the construction machine has a merging passage that merges the 1 st hydraulic oil discharged from the 1 st pump and the 2 nd hydraulic oil discharged from the 2 nd pump when the operation body is operated,
a check valve for blocking the flow from the 2 nd pump to the 1 st pump is disposed in the merging line.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014219590A JP6305902B2 (en) | 2014-10-28 | 2014-10-28 | Work machine |
| JP2014-219590 | 2014-10-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105544630A CN105544630A (en) | 2016-05-04 |
| CN105544630B true CN105544630B (en) | 2020-12-15 |
Family
ID=55824150
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510712772.2A Active CN105544630B (en) | 2014-10-28 | 2015-10-28 | Construction machine |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP6305902B2 (en) |
| CN (1) | CN105544630B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102461096B1 (en) * | 2017-07-20 | 2022-10-31 | 현대두산인프라코어 주식회사 | Method and apparatus for controlling travelling speed of construction machinery |
| JP7131138B2 (en) * | 2018-07-04 | 2022-09-06 | コベルコ建機株式会社 | Working machine hydraulic drive |
| KR102086144B1 (en) * | 2018-10-16 | 2020-03-06 | 현대건설기계 주식회사 | Hydraulic Control System for Construction Equipment |
| CN115404938B (en) * | 2022-10-08 | 2023-10-03 | 三一海洋重工有限公司 | Control method and device for grabbing hopper and grabbing machine |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5686205A (en) * | 1979-12-17 | 1981-07-13 | Hitachi Constr Mach Co Ltd | Oil pressure circuit for composite accutuation |
| JP4700077B2 (en) * | 2008-03-26 | 2011-06-15 | 株式会社クボタ | Display device for work equipment |
| CN201211860Y (en) * | 2008-04-15 | 2009-03-25 | 海南金鹿农机发展股份有限公司 | Palm fruit grab-bucket tractor |
| JP2011247282A (en) * | 2010-05-21 | 2011-12-08 | Hitachi Constr Mach Co Ltd | Hydraulic driving device for wheel type working machine |
| JP2012021311A (en) * | 2010-07-14 | 2012-02-02 | Hitachi Constr Mach Co Ltd | Hydraulic driving device for construction machine |
| JP2012132180A (en) * | 2010-12-21 | 2012-07-12 | Hitachi Constr Mach Co Ltd | Working machine |
| CN102259793A (en) * | 2011-05-16 | 2011-11-30 | 杭州电子科技大学 | Electric six-blade hydraulic grab bucket |
| JP5356477B2 (en) * | 2011-09-06 | 2013-12-04 | 住友建機株式会社 | Construction machinery |
-
2014
- 2014-10-28 JP JP2014219590A patent/JP6305902B2/en active Active
-
2015
- 2015-10-28 CN CN201510712772.2A patent/CN105544630B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP6305902B2 (en) | 2018-04-04 |
| CN105544630A (en) | 2016-05-04 |
| JP2016084910A (en) | 2016-05-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107075838B (en) | Machine tool | |
| CN107614896B (en) | Shovel and method for driving shovel | |
| CN105544630B (en) | Construction machine | |
| US10995475B2 (en) | Construction machine | |
| US9903393B2 (en) | Construction machine | |
| KR102460499B1 (en) | shovel | |
| EP2568181A1 (en) | Hydraulic control device for work vehicle | |
| KR20200022400A (en) | Shovel and shovel control method | |
| JP6231917B2 (en) | Hydraulic excavator drive system | |
| KR101747519B1 (en) | Hybrid construction machine | |
| CN106460877B (en) | Excavator and its control method | |
| CN107882789B (en) | Electro-hydraulic system with negative flow control | |
| CN110291254B (en) | Excavator | |
| CN107217694B (en) | Excavator | |
| US11434937B2 (en) | Excavator and control valve for excavator | |
| CN111344459B (en) | Drive system for construction machine | |
| US11454002B2 (en) | Hydraulic drive system for work machine | |
| EP3995632A1 (en) | Construction machinery | |
| CN111465737A (en) | Excavator | |
| JP6640039B2 (en) | Excavator | |
| JP6488990B2 (en) | Hydraulic drive device for cargo handling vehicle | |
| WO2020071044A1 (en) | Hydraulic shovel drive system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |