JP3541116B2 - Hydraulic control device for work equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for avoiding contact between a driving unit such as a cabin and a bucket of an excavating work device in a backhoe.
[0002]
[Prior art]
A backhoe employing a structure in which the boom bends sideways or the like is provided with interference prevention control means for avoiding contact between the driving unit and the bucket. That is, a traction surface is provided assuming a predetermined distance forward and laterally away from the driving unit, and the bucket approaches and moves toward the driving unit, and a reference portion of the bucket (usually, When (set) reaches the check surface, the approach movement is stopped, and the check is performed so that interference between the bucket and the operating unit does not occur. For example, the one disclosed in JP-A-6-17452 is known.
[0003]
[Problems to be solved by the invention]
In the above-described conventional configuration, even when the bucket moves so as to approach the driving unit with a component that is separated from the driving unit in the lateral direction (see FIG. 6), the front restraint surface A1 or the lateral restraint surface is used. When the bucket reaches A2, the operation is controlled to be stopped.
[0004]
Then, when moving the bucket from the front of the driving unit to the lateral side of the driving unit to raise the boom to shift from the excavation to the turning posture, as shown by the arrow in FIG. It is preferable that the bucket is moved obliquely as if it grabs a corner where the first horizontal check surface A2 intersects, in that the quick movement can be performed. If the vehicle is moved obliquely in the state of interference, the movement is stopped by the interference prevention control when the vehicle reaches the front restraint surface A1.
[0005]
Therefore, in that case, it is necessary to manually move the reference portion of the bucket to a position away from the front restraint surface A1 and the lateral restraint surface A2 by moving the arm to the earth discharging side, and the operation is troublesome and troublesome. It is difficult to move the excavation work equipment smoothly, and the work efficiency is not good. Therefore, when the bucket reaches the front restraint surface A1 (or when the bucket approaches very close), the arm is moved to the discharging side to automatically operate the bucket so that the bucket does not approach the operation unit side from the restraint surface, thereby raising the boom. It was conceived that the operation and the offset movement to the right side of the boom would be continued to continue without stopping the movement as the excavation work device.
[0006]
For example, as shown in FIG. 13, a pilot-operated circuit in which the arm control valve 22 is operated by the pressure of manually operated pilot valves 32a and 32b, the reference portion of the bucket reaches (or approaches) the check surface. The check surface detecting means 48 for detecting that the operation has been performed and the electromagnetic switching valve 49 for controlling whether or not to supply the pilot pressure to the arm discharging side of the arm control valve 22 are provided to the arm discharging side automatic operation control means 50. Connecting. That is, when the bucket reference portion reaches (or approaches) the check surface, the electromagnetic switching valve 49 is switched to the pressure supply position, and the control for forcibly switching the arm control valve 22 to the earth discharging side is performed.
[0007]
However, since it is necessary to allow the arm to escape to the earth discharging side by manual operation, as shown in FIG. 13, the higher of the pressure of the manual operation system by the pilot valve 32b and the pilot pressure by the automatic control, Are supplied to the arm control valve 22. In this case, two check valves 52, 52 (or a shuttle valve) are provided. That is, two check valves or shuttle valves are required in addition to the electromagnetic proportional changeover valve, so that the cost is high and the circuit becomes complicated, so that there is room for further improvement. I think.
[0008]
Therefore, an object of the present invention is to enable continuous movement of the excavation work device by automatically escaping the arm to the earth discharging side even when the bucket approaches the check surface when the bucket is obliquely moved as described above, An object of the present invention is to economically and rationally realize a device that can smoothly move without troublesome avoiding and moving operation of a bucket and improves operability of an excavating device.
[0009]
[Means for Solving the Problems]
〔Constitution〕
The first invention isA pilot valve that communicates with the tank in a normal state and supplies pilot pressure to the control valve by manual operation, and a switching valve is interposed in a pilot oil passage between the pilot valve and the control valve;With pilot pressure from pilot valveSaidArtificial operation system that can operate control valve and command of control meansSwitch the switching valve from the pilot pumpA control operation system capable of automatically operating the control valve with pilot pressure is provided,
SaidThe switching valve has the aforementionedA control operation position connecting a pump port communicating with a pilot pump and a valve port communicating with the control valve, and an artificial operation position connecting a pilot port communicating with the pilot valve and the valve port.Be preparedA return spring biasing the manual operation position, and an operation oil passage in which pressure generated in the valve port acts in a direction for switching the switching valve to the manual operation position.With,
The switching valve is moved between the manual operation position and the control operation position by a command of the control means.AlternatelyConfiguration for quick switching operationAnd controlling the higher pressure between the pilot pressure on the valve port side of the switching valve generated by operation from the artificial operation system and the pilot pressure on the valve port side of the switching valve generated by control from the control operation system. Features a pilot pressure adjustment mechanism for supplying to the valve.
[0010]
According to a second aspect of the present invention, in the first aspect, the arm control valve is operable by a pilot pressure for an arm discharging operation from an artificially operated pilot valve to constitute an artificial operation system,
The operation of the excavating work device is controlled based on the detection information of the position sensor that detects the position of the bucket, so as to prevent interference between the bucket and the operating unit. When the vehicle approaches the check surface set near, the arm control valve is automatically operated so as to drive the arm to the earth discharging side to avoid the bucket from approaching the operating unit from the check surface. A control operation system is configured.
[0011]
[Action]
According to the above characteristic configuration, it will be described in detail in the embodiment section,Occurs on the valve port side of the switching valve in the pilot oil passageSince the pilot pressure adjusting mechanism that supplies the higher pressure of the pilot pressure of the artificial operation system and the pilot pressure of the control operation system to the arm control valve can be constituted by only one switching valve, As compared with the comparative example shown in FIG. 13, the number of parts is small, the structure is simple, and it is possible to configure the device at low cost.
[0012]
In other words, in a boom offset type backhoe, in the work of turning the scooped earth and sand and then loading it on a distant truck bed, as described above, in order to scoop up the earth and sand by operating the arm and set it in the turning posture, as described above Then, the bucket is steered to move obliquely as if the corner portion where the front restraint surface A1 and the first lateral restraint surface A2 intersect was grabbed. Therefore, in the configuration of claim 2, the switching valve forcibly switches the arm control valve to the earth discharging side in response to a detection signal indicating that the reference portion of the bucket has reached (or approached) the front restraint surface A1, and the bucket is switched. Since the control is performed so as to keep the front restraint surface A1 away from the front, the boom can be continued to be raised, and the bucket can be quickly shifted to the turning posture in which the bucket is stored on the right side of the operating unit.
[0013]
The configuration of claim 1 is applied as a hydraulic control device of a working machine having a control operation system and an artificial operation system, such as a hydraulic circuit for elevating and lowering a dozer of a dozer working machine and a hydraulic circuit for elevating a combine harvester. Is possible.
[0014]
〔effect〕
As a result, in the hydraulic control circuit according to the first or second aspect, a pilot pressure adjusting mechanism that supplies a higher one of the pilot pressure of the manual operation system and the pilot pressure of the control operation system to the control valve is more structured than the conventional one. It was simple, cost-effective, economical and rational.
[0015]
In the hydraulic control circuit according to the second aspect, even if the bucket is obliquely moved laterally from the front of the operation unit so as to interfere with the tread surface, the excavation work device can be continuously driven without stopping halfway, and more quickly. There is an advantage that it becomes suitable for a pilot operation system of a backhoe that can be moved to a bucket and has excellent operability.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows the entire side surface of the backhoe, in which a swivel 2 is supported by a rubber crawler type traveling device 1, and an excavation work device 3 is provided in front of the swivel 2. The excavating work device 3 includes a boom 4 that is vertically oscillated by a hydraulic cylinder 11, an arm 5 that is oscillated back and forth by a hydraulic cylinder 12, and a bucket 6 that is oscillated by a hydraulic cylinder 13. Have been.
[0017]
The boom 4 of the excavating work device 3 includes a first boom portion 4a that is vertically operated to swing, a second boom portion 4b that is swingably connected around an axis P1 at a front end of the first boom portion 4a, and a second boom portion. A support bracket 4c is swingably connected around the axis P2 at the front end of the boom portion 4b, and the arm 5 is connected to the support bracket 4c. An interlocking link 8 is laid across the first boom portion 4a and the support bracket 4c to form a parallel quadruple link, and the hydraulic cylinder 7 swings the second boom portion 4b to move the arm 5 and the A so-called offset operation is performed in which the bucket 6 is moved left and right in parallel.
[0018]
As shown in FIGS. 1 and 5, in the swivel 2, an excavation work device 3 is disposed on the right side, and a driver's seat 14 and an operation unit 15 including right and left operation levers 9 and 10 are disposed on the left side. I have. At the left and right center of the swivel 2, there is provided a vertical partition 16 with a window separating the excavating work device 3 and the operating unit 15, and an upper partition along the outside of the swivel 2 at the upper end of the vertical partition 16. 17 is fixed.
[0019]
Next, an operation structure of the hydraulic circuit structure, the excavating work device 3, the swivel 2 and the like will be described.
As shown in FIG. 2, the control valve 21 of the hydraulic cylinder 11 of the first boom portion 4a (boom 4), the control valve 22 of the hydraulic cylinder 12 of the arm 5, the control valve 23 of the hydraulic cylinder 13 of the bucket 6, and the swivel 2 , The control valve 24 of the hydraulic motor 7 of the second boom portion 4b, the control valve 26 of the right traveling device 1, the control valve 27 of the left traveling device 1, and a service port (not shown). , And a control valve 29 of a hydraulic cylinder 51 for raising and lowering the dozer 19 shown in FIG. 1, and hydraulic oil from a pump 20 is supplied to the control valves 21 to 29.
[0020]
The control valve 21 of the first boom portion 4a, the control valve 22 of the arm 5, the control valve 23 of the bucket 6, the control valve 24 of the swivel 2 and the control valve 25 of the second boom portion 4b are pilot operated by pilot pressure. Neutral return type. The control valves 26 and 27 of the right and left traveling devices 1, the control valve 28 of the service port, and the control valve 29 of the dozer 19 are mechanically operated and neutral return type operated by operation levers (not shown).
[0021]
As shown in FIG. 3, the right operating lever 9 is configured to be operable forward, backward, left and right, and a pilot valve 31 a that generates a pilot pressure by a rear operation of the right operating lever 9, and a pilot pressure by a front operation of the right operating lever 9. , A pilot valve 33a that generates pilot pressure by operating the right operating lever 9 to the right, and a pilot valve 33b that generates pilot pressure by operating the right operating lever 9 to the left.
[0022]
Similarly, the left operation lever 10 is also configured to be operable in the front, rear, left and right directions. A pilot valve 32a that generates a pilot pressure by a rear operation of the left operation lever 10 and a pilot valve that generates a pilot pressure by a front operation of the left operation lever 10. A valve 32b, a pilot valve 34a that generates pilot pressure by operating the left operating lever 10 to the right, and a pilot valve 34b that generates pilot pressure by operating the left operating lever 10 to the left are provided.
[0023]
As shown in FIG. 3, an operation pedal 39 is provided which can be freely depressed left and right. A pilot valve 35 a that generates a pilot pressure when the operation pedal 39 is depressed left, and a pilot pressure that is generated when the operation pedal 39 is depressed right. A pilot valve 35b for generating is provided. A pilot pump 30 that supplies pilot pressure to the pilot valves 31a to 35b is provided.
[0024]
As shown in FIGS. 2 and 3, the pilot valves 31a and 31b of the right operating lever 9 and the control valve 21 of the first boom portion 4a, the pilot valves 33a and 33b of the right operating lever 9 and the control valve 23 of the bucket 6 are connected to each other. The pilot valves 32a and 32b of the left operating lever 10 and the control valve 22 of the arm 5, the pilot valves 34a and 34b of the left operating lever 10 and the control valve 24 of the swivel 2 are connected to each other. , Are connected via a pilot oil passage. The pilot valves 35a and 35b of the operation pedal 39 and the control valve 25 of the second boom portion 4b are connected via a pilot oil passage.
[0025]
When the right operation lever 9 is operated backward by the above-described structure, the control valve 21 is operated toward the rising side of the first boom portion 4a (extension side of the hydraulic cylinder 11) by the pilot pressure from the pilot valve 31a, and the right operation lever 9 is operated. When the pre-operation is performed, the control valve 21 is operated on the lowering side of the first boom portion 4a (the contracting side of the hydraulic cylinder 11) by the pilot pressure from the pilot valve 31b. When the right operation lever 9 is operated to the right, the control valve 23 is operated to the discharging side of the bucket 6 (the contraction side of the hydraulic cylinder 13) by the pilot pressure from the pilot valve 33a, and when the right operation lever 9 is operated to the left, the pilot valve 33b is operated. , The control valve 23 is operated to the side where the bucket 6 is squeezed (the side where the hydraulic cylinder 13 is extended).
[0026]
When the left operating lever 10 is operated backward, the control valve 22 is operated to the squeezing side of the arm 5 (extended side of the hydraulic cylinder 12) by the pilot pressure from the pilot valve 32a, and when the left operating lever 10 is operated forward, the pilot valve 32b is operated. The control valve 22 is operated to the earth discharging side of the arm 5 (the contracting side of the hydraulic cylinder 12) by the pilot pressure from. When the left operating lever 10 is operated to the right, the control valve 24 is operated to the right turning side of the swivel 2 by the pilot pressure from the pilot valve 34a, and when the left operating lever 10 is operated to the left, the pilot pressure from the pilot valve 34b is used. , The control valve 24 is operated to the left turning side of the swivel 2.
[0027]
When the operation pedal 39 is depressed to the left, the control valve 25 of the second boom portion 4b is operated to the left swing side (extension side of the hydraulic cylinder 7) by the pilot pressure from the pilot valve 35a, and the operation pedal 39 is depressed to the right. Then, the control valve 25 of the second boom portion 4b is operated to the right swing side (the contraction side of the hydraulic cylinder 7) by the pilot pressure from the pilot valve 35b.
[0028]
The pilot pressure of the pilot valves 31a to 35b increases as the right and left operation levers 9, 10 and the operation pedal 39 are operated from the neutral position. Thus, as the right and left operating levers 9, 10 and the operating pedal 39 are operated from the neutral position, the pilot pressures of the pilot valves 31a to 35b are increased, and the control valves 21 to 25 are operated to the larger flow rate side. That is, as the right and left operation levers 9 and 10 and the operation pedal 39 are operated larger, the hydraulic cylinders 7, 11, 12, 13 and the turning motor 18 operate at a higher speed.
[0029]
Next, the front restraint surface A1, the first lateral restraint surface A2, the second transverse restraint surface A3, and the like set for the swivel 2 will be described.
As shown in FIGS. 4 and 5, the front restraint surface A <b> 1 separated by a predetermined distance ahead of the front edge of the vertical partition 16 and the front edge of the upper partition 17, and the horizontal side of the vertical partition 16. A lateral first restraint surface A2 separated by a predetermined distance to the right and a lateral second restraint surface A3 further outward are assumed, and are set in the control device 40 (see FIG. 3) as control means. Here, the vertical partition plate 16 and the upper partition plate 17 are referred to as an external frame.
[0030]
In this case, even when the bucket pin 6a connecting the bucket 6 to the tip of the arm 5 is located on the front restraint surface A1, even if the bucket 6 is swung so as to be closest to the driving unit 15 side, the vertical The front restraint surface A1 is set such that the tip of the bucket 6 is located on a trajectory C1 separated from the front edge of the partition plate 16 and the front edge of the upper partition plate 17 by a predetermined distance. In a state where the bucket pin 6a is located on the first horizontal braking surface A2, the first horizontal braking surface A2 is set such that the left lateral surface of the bucket 6 is located on the locus C2 separated from the vertical partition plate 16 by a predetermined distance. ing.
[0031]
A surface separated from the front and first lateral restraint surfaces A1 and A2 by a predetermined distance to the front or right is set, and a space between the space and the front and first lateral restraint surfaces A1 and A2 is a front restraint region B1. And in the control device 40 as the first lateral restraint area B2. The outer side surface of the lateral restraint region B2 is referred to as a second lateral restraint surface A3. Further, a third lateral restraint surface is provided outside the second lateral restraint surface A3, and a second lateral restraint region B3 is provided between the second lateral restraint surface A3 and the third lateral restraint surface.
The front and side first and second restraint surfaces A1, A2, A3 and the front and side restraint areas B1, B2, B3 as described above are set with respect to the turntable 2, and the turntable 2 turns. With this, it moves together with the swivel 2.
[0032]
As shown in FIGS. 1 and 4, an angle sensor 36 for detecting the vertical angle of the first boom portion 4a with respect to the swivel 2 is provided at a connection between the swivel 2 and the first boom portion 4a. An angle sensor 37 for detecting a left-right angle of the second boom portion 4b with respect to the first boom portion 4a is provided at a connecting portion between the second boom portions 4a and 4b. An angle sensor 38 for detecting a front-rear angle of the arm 5 with respect to the second boom portion 4b is provided at a connection between the support bracket 4c and the arm 5. Here, the angle sensors 36, 37, 38 are referred to as position sensors.
[0033]
The detection values of the angle sensors 36, 37, and 38 as described above are input to the control device 40, and based on the detection values of the angle sensors 36, 37, and 38, as described later, the front and the horizontal first and second The control device 40 detects the positions of the bucket pins 6a with respect to the check surfaces A1, A2, A3, the front and side check regions B1, B2.
As shown in FIG. 3, a pilot oil passage connecting the pilot valve 31a of the right operation lever 9 and the control valve 21 of the first boom portion 4a (the pilot oil passage for operating the control valve 21 of the first boom portion 4a upward). Path), a pilot oil path that connects the pilot valve 32a of the left operating lever 10 and the control valve 22 of the arm 5 (a pilot oil path that operates the control valve 22 of the arm 5 to the rake side), and a pilot oil path of the operation pedal 39. Each of the pilot oil passages connecting the valve 35a and the control valve 25 of the second boom portion 4b (the pilot oil passage for operating the control valve 25 of the second boom portion 4b to the left swing side) has an electromagnetically operated pressure. Control valves 41, 42, 43 are provided.
[0034]
Therefore, the pilot pressure is reduced by the pressure control valves 41, 42, 43 (the maximum pressure is the value set by the right and left operation levers 9, 10 and the operation pedal 39), and the right and left operation levers 9, 10 Irrespective of the operating position of the operating pedal 39, the opening of the control valve 21 of the first boom portion 4a on the rising side, the opening of the control valve 22 of the arm 5 on the scraping side, and the control valve 25 of the second boom portion 4b. Can be changed arbitrarily. By setting the pilot pressure to zero by the pressure control valves 41, 42, 43, the hydraulic cylinder 11 of the first boom portion 4 a, the arm 5, regardless of the operating positions of the right and left operating levers 9, 10 and the operating pedal 39. The hydraulic cylinder 12 of the second boom portion 4b can be stopped.
[0035]
Next, the relationship between the excavation work device 3 and the restraint areas B1, B2, and B3 will be described. In this case, it is necessary to define the position of the bucket 6. Therefore, here, the control is performed using the bucket pin 6 a as the reference position of the bucket 6. As shown in FIG. 8, the controller 40 detects the vertical angle of the first boom part 4 a, the horizontal angle of the second boom part 4 b, the front-rear angle of the arm 5 based on the detection values of the angle sensors 36, 37, and 38, and the first boom. The position of the bucket pin 6a is always detected based on the length of the portion 4a, the second boom portion 4b, and the length of the arm 5.
[0036]
Therefore, based on the detection result, it is determined in which area the position of the bucket pin 6a is located, and the case where the bucket pin 6a is in the front restraint area B1, the case where the bucket pin 6a is in the lateral restraint area B2, B3, and the two restraint areas B1, B2 , B3, the control corresponding to the case where the vehicle is in the other region located outside the vehicle, ie, the front restraint control when the vehicle is in the front restraint region B1, and the lateral restraint when the vehicle is in the lateral restraint regions B2 and B3. The control and the normal control when it is in another area are performed (S100 to S103).
[0037]
FIG.As shown in the figure, in the normal control, when there is a command to move the first boom portion 4a up and down, the boom is moved up and down based on the operation of the left and right operation levers 10 and 9 and the operation pedal 39. 5, when there is an operation command to the earth discharging side and the scraping side, the arm 5 is caused to perform the forward and backward movement, and when there is an operation command to swing the second boom part 4b left and right, the second boom part 4b and the arm Then, a so-called offset operation is performed in which the first and the fifth are integrally swung left and right (S201 to S206).
[0038]
In this control, the moving speed of the first boom portion 4a and the like is set so as not to be reduced. When the position of the bucket pin 6a reaches the second lateral restraint surface A3 of the lateral restraint area B2 in the state where the above-described normal control is being performed, a left swing command is issued to the boom, that is, the second boom portion 4b. In this case, the swing operation to the left is stopped (S207 to S209). In other words, the presence of the left swing command means that the bucket 6 at least enters the driving unit 15. In this case, the outer second lateral restraint surface is considered in consideration of the inertia of the bucket 6. A stop operation is performed at A3. Therefore, when moving in a direction away from the driving unit 15 by a swing command to the right, normal control is performed.
[0039]
Shown in FIG.The front restraint control will be described. First, an operation when an operation command is issued to the excavation work device 3 will be described. That is, when a vertical movement command is issued to the boom 4, the following control is performed.4 and 5 show the bucket pin 6a.When entering the front restraint area B1 shown inAnd, Right operating lever 9 is later operated to raise first boom portion 4aWhenThe handling before the bucket pin 6a reaches the front restraint surface A1 is performed as follows.
[0040]
In this case, a specific operation mode is such that the pilot pressure of the pilot valve 31a is reduced by the pressure control valve 41 shown in FIG. The ascending speed (extension speed of the hydraulic cylinder 11) is decelerated, and as the bucket pin 6a approaches the front restraint surface A1, the ascent speed of the first boom portion 4a (extension speed of the hydraulic cylinder 11) is greatly reduced. The operation is performed (S301, 302, 305). The case where the bucket pin 6a has reached the front restraint surface A1 (S303, 304) will be described later.
[0041]
Conversely, when the right operation lever 9 is operated forward to lower the first boom portion 4a, the bucket pin 6a is separated from the front restraint surface A1, so that the bucket pin 6a is moved to the front restraint surface A1 and the front restraint area B1. , Regardless of this, the first boom portion 4a is lowered at a speed corresponding to the operation position of the previous operation of the right operation lever 9 (S306) (the right operation lever as shown in FIG. 3). 9 because the pressure control valve 41 is not provided in the pilot oil passage of the pilot valve 31b).
[0042]
When a vertical movement command is issued to the boom 4 in the front restraint area B1, the following control is performed. In a state where the bucket pin 6a has entered the front restraint area B1 (S307), when the left operating lever 10 is operated backward to squeeze the arm 5, the bucket pin 6a is brought into a state of approaching the front restraint surface A1 (S308). ).
[0043]
In this state, the pilot pressure of the pilot valve 32 a is reduced by the pressure control valve 42 shown in FIG. 3, and regardless of the operation position of the rear operation of the left operation lever 10, the scraping speed of the arm 5 (the extension speed of the hydraulic cylinder 12). ), The more the bucket pin 6a approaches the front restraint surface A1, the greater the speed at which the arm 5 is squeezed (the extension speed of the hydraulic cylinder 12) is reduced (S308, 310). When the bucket pin 6a reaches the front restraint surface A1 (S308), the pilot pressure of the pilot valve 32a is set to zero by the pressure control valve 42 shown in FIG. 3, regardless of the operation position of the rear operation of the left operation lever 10. The control valve 22 is operated to the neutral position, and the arm 5 (the hydraulic cylinder 12) stops (S309).
[0044]
Conversely, when the left operation lever 10 is operated forward and the arm 5 is operated to the earth discharging side (S307), the bucket pin 6a is separated from the front restraint surface A1, so that the bucket pin 6a is moved to the front restraint surface A1 and the front restraint surface A1. Even if it is located in the front restraint area B1, the arm 5 is operated to the earth discharging side at a speed corresponding to the operation position of the front operation of the left operation lever 10 regardless of this (S311) (as shown in FIG. 3). (This is because the pressure control valve 42 is not provided in the pilot oil passage of the pilot valve 32b of the left operation lever 10).
[0045]
When the bucket pin 6a has entered the front restraint area B1, the operation pedal 39 is depressed to swing the second boom portion 4b, and the bucket pin 6a approaches the front restraint surface A1 (S315). ).
In this state, the pilot pressure of the pilot valve 35a is reduced by the pressure control valve 43 shown in FIG. 3, and the left swing speed of the second boom portion 4a (regardless of the operation position of the left pedal operation of the operation pedal 39) ( As the bucket pin 6a approaches the front restraint surface A1, the left swing speed (extension speed of the hydraulic cylinder 7) of the second boom portion 4a increases as the bucket pin 6a approaches the front restraint surface A1. Is performed (S317). When the bucket pin 6a reaches the front restraint surface A1 (S313), the pilot pressure of the pilot valve 35a is set to zero by the pressure control valve 43 shown in FIG. 3, regardless of the operation position of the left pedal operation of the operation pedal 39. The control valve 25 is operated to the neutral position, and the second boom portion 4b (the hydraulic cylinder 7) stops (S314).
[0046]
Conversely, when the operation pedal 39 is depressed to swing the second boom portion 4b toward the opposite side (S315), the bucket pin 6a is separated from the front restraint surface A1, and the bucket pin 6a is moved forward. The second boom portion 4b is rocked at a speed corresponding to the operation position of the depressing operation of the operation pedal 39 regardless of the position even in the braking surface A1 and the front braking region B1 (S316) (FIG. As shown in FIG. 3, the pressure control valve 43 is not provided in the pilot oil passage of the pilot valve 35b of the operation pedal 39).
[0047]
Next, a description will be given of a case where the bucket pin 6a reaches the front restraint surface A1 by the raising operation of the first boom portion 4a (S302) and a case where the bucket pin 6a reaches the front restraint surface A1 by the scraping operation of the arm 5. I do.
As shown in FIG. 3, an electromagnetically operated switching valve (an example of a pilot pressure adjusting mechanism E) is provided in a pilot oil passage 45 between the arm discharging pilot valve 32b of the left operating lever 10 and the arm control valve 22. 44 is interposed.
[0048]
The switching valve 44pilotA control operation position 44a connecting a pump port p communicating with the pump 30 and a valve port v communicating with the arm control valve 22, and a pilot port r communicating with the arm discharging pilot valve 32b and a valve port v are connected. And a two-position switching type high-speed electromagnetic response valve having a manually operated position 44b. Then, a return spring 46 which normally urges the switching valve 44 to maintain the manual operation position 44b, and an operation oil passage 47 in which the pressure generated in the valve port v acts in the direction of switching the switching valve 44 to the manual operation position 44b. And a command from a control device (an example of control means) 40When receiving the electromagnetic force generated by the control signal (pulse signal)The switching valve 44 is moved between the manual operation position 44b and the control operation position 44a.Switch quickly to each otherIt is configured as follows.
[0049]
For example, the right operating lever 9By post operationRaising the first boom part 4aWhen the bucket pin 6a reaches the front restraint surface A1 due to the control signal (pulse signal) by the control device 40,At the same time that the pressure control valve 41 is switched to the open side,In normal position (normal)The switching valve 44 at the manual operation position 44b continuously reciprocates in an oscillatory manner between the manual operation position 44b and the control operation position 44a,Pilot pump 3 Pressure oil from 0 passes through the pump port p and the valve port v at the control operation position 44a of the switching valve 44, and is located on the lower side of the flow path from the switching valve 44 on the arm discharge side.The pilot pressure rises at the control valve 22 side portion of the pilot oil passage 45.
[0050]
As a result, the pilot pressure from the pilot pump 30 is supplied to both the first boom portion control valve 21 (upward side) and the arm control valve 22 (discharge side), and the first boom portion 4a is turned off. Simultaneously with the raising operation (extension of the hydraulic cylinder 11) at the minimum speed (S303), the arm 5 is operated to the earth discharging side (the hydraulic cylinder 12 contracts) (S304). In this case, the moving speed of the arm 5 to the earth discharging side may be made sufficiently high so that the rising speed of the first boom portion 4a is not reduced.
[0051]
When the above operation is performed, the first boom portion 4a is raised and the angle D between the second boom portion 4a and the arm 5 is gradually increased as shown in FIG. As a result, the bucket pin 6a rises along the front restraint surface A1 (the position of the bucket pin 6a is detected while detecting the position of the bucket pin 6a based on the detection values of the angle sensors 36, 37, and 38). The switching speed of the switching valve 44 is set by the control device 40 so that is always located on the front restraint surface A1, and thereby the pilot pressure to the arm control valve 22 (discharge side) is controlled). Simultaneously, when the right operation lever 9 is operated to the left to rake the bucket 6, the bucket 6 can be maintained horizontal.
[0052]
As described above, during the operation of the arm discharge side automatic operation control for operating the switching valve 44 by the operation of the control device 40 and automatically moving the arm to the discharge side (or starting the control thereof). Simultaneously), when the arm discharging pilot valve 32b is manually operated to move the arm 5 to the discharging side, the resulting artificial pilot pressure acts on the pilot port r of the switching valve 44. Then, since the switching valve 44 reciprocates between the two positions during the control, the artificial pilot pressure is also supplied to the operating oil passage 47 to act to urge the switching valve 44 to the artificial operating position 44b.
[0053]
Therefore,An operation oil path in which an artificial oil pressure in a pilot oil path 45 on the valve port v side of the switching valve 44 in which an operation oil path 47 generated by manually operating the arm discharging pilot valve 32b exists is provided by a command from the control device 40. Pilot pressure (control pilot pressure) in the pilot oil passage 45 on the valve port v side of the switching valve 44 in which 47 exists.When it is higher than the above, the sum of the force of the return spring 46 and the force of the artificial pilot pressure acting on the operation oil passage 47 becomes larger than the electromagnetic force for operating the switching valve 44 to the control operation position 44a. Therefore, the switching valve 44 is kept biased to the manual operation position 44b,Higher pilot pressure due to manual operation (artificial pilot pressure)Is for the armControl valve22, the arm 5 is quickly moved to the earth discharging side, and the bucket 6 can be moved forward from the front restraint surface A1.
[0054]
In addition, even if the arm discharging pilot valve 32b is manually operated, the operation amount is reduced.LessWhen the artificial pilot pressure is lower than the control pilot pressure, the electromagnetic force for operating the switching valve 44 to the control operation position 44a is smaller than the sum of the force of the return spring 46 and the force of the artificial pilot pressure acting on the operation oil passage 47. Higher, because the switching valve 44 reciprocates between the two positions.IsThe control pilot pressure is supplied to the arm control valve 22, and the state in which the pilot pressure to the arm control valve 22 (discharge side) is controlled such that the bucket pin 6a is always located on the front restraint surface A1 is continued. You.
[0055]
In the present hydraulic circuit, the artificial operation system JS is provided by the arm discharging pilot valve 32b and the pilot oil passage 45 thereof, and the control operation system SS is provided by the control device 40 for performing the arm discharging side automatic operation control. Each is configured.
[0056]
Next, the lateral restraint control will be described. In this lateral restraint control, since the control mode when the bucket pin 6a is located in the first lateral restraint area B2 and the second lateral restraint area B3 is almost the same, the bucket pin 6a is located in the first lateral restraint area B2. Will be mainly described, and only the different point will be described when it is located in the second lateral restraint area B3.
[0057]
Control from a state where the position of the bucket pin 6a is located in the first lateral restraint region B2 will be described. First, there is a problem whether an offset operation command is issued and whether the command indicates leftward swing (S401). When the operation pedal 39 is depressed to the left and the second boom portion 4b is pivoted to the left, the bucket pin 6a is brought into a state of approaching the first lateral braking surface A2 (S404).
[0058]
In this state, the pilot pressure of the pilot valve 35a is reduced by the pressure control valve 43 shown in FIG. 3, and the left swing speed of the second boom portion 4b (regardless of the operation position of the left pedal operation of the operation pedal 39) ( The extension speed of the hydraulic cylinder 7) is decelerated (S404), and as the bucket pin 6a approaches the lateral restraint surface A2, the left swing speed (extension speed of the hydraulic cylinder 7) of the second boom portion 4b increases. It is greatly decelerated. When the bucket pin 6a reaches the first lateral restraint surface A2, the pilot pressure of the pilot valve 35a is set to zero by the pressure control valve 43 shown in FIG. The valve 25 is operated to the neutral position, and the second boom portion 4b (the hydraulic cylinder 7) stops (S403).
[0059]
Conversely, when the operation pedal 39 is depressed to the right and the second boom portion 4b is pivoted to the right, the bucket pin 6a is separated from the first lateral restraint surface A2, and the bucket pin 6a is moved to the first lateral restraint. Even if it is located on the surface A2 and the first lateral restraint area B2, the second boom portion 4b is operated to swing right at a speed corresponding to the operation position of the right depression operation of the operation pedal 39 regardless of this (FIG. As shown in FIG. 3, the pressure control valve 43 is not provided in the pilot oil passage of the pilot valve 35b of the operation pedal 39) (S405).
[0060]
In a state where the bucket pin 6a has entered the first lateral restraint area B2, even if the first boom portion 4a is raised and lowered, or the arm 5 is operated on the scraping side and the earth discharging side, the bucket pin 6a is Since the bucket pin 6a does not enter the lateral first restraining area B2 because the bucket pin 6a does not approach the lateral first restraining surface A2, the raising and lowering operations of the first boom portion 4a, the scraping side of the arm 5, and the discharge The operation on the soil side can be freely performed (S406 to S409).
[0061]
When the bucket pin 6a is located in the second lateral restraint area B3, the control shown in other steps is simply performed by switching the first lateral restraint plane A2 to be determined in step S402 to the second lateral restraint plane A3. Can be used as is.
[Brief description of the drawings]
FIG. 1 is an overall side view of a backhoe.
FIG. 2 is a hydraulic circuit diagram showing a hydraulic cylinder, a control valve, and the like of the excavating work device.
FIG. 3 is a hydraulic circuit diagram showing a pilot operation system.
FIG. 4 is a side view showing a front restraint surface and a front restraint area.
FIG. 5 is a plan view showing front and side restraint surfaces and front and side restraint areas.
FIG. 6 is a plan view showing a state where the bucket enters the lateral restraint region from the front.
FIG. 7 is a plan view showing a state where the bucket enters the lateral restraint region from the side.
FIG. 8 is an overall control flowchart.
FIG. 9 is a normal control flowchart.
FIG. 10 is a flowchart showing the first half of the control flow in the front restraint surface and the front restraint area.
FIG. 11 is a flowchart showing the latter half of the control flow in the front restraint surface and the front restraint area.
FIG. 12 is a flowchart showing lateral restraint control.
FIG. 13 is a hydraulic circuit diagram showing a comparative example of a pilot operation system.
[Explanation of symbols]
3 Excavation work equipment
4 Boom
5 arm
6 buckets
15 Driving unit
22 Control valve
30 Pilot pump
32b pilot valve
36,37,38 Position sensor
40 control means
44 Switching valve
44a Control operation position
44b Artificial operation position
46 Return spring
47 Operation oil passage
A1, A2 check surface
JS artificial operation system
SS control operation system
E Pilot pressure adjustment mechanism
p pump port
r Pilot port
v Valve port

Claims (2)

A pilot valve (32b) which is normally in communication with the tank and supplies pilot pressure to the control valve (22) by manual operation, and a pilot oil between the pilot valve (32b) and the control valve (22); road interposed a switching valve (44) to (45), a manually operated system operable said control valve a pilot pressure (22) from the pilot valve (32 b), more command from the control means (40) A control operation system that can automatically operate the control valve (22) with the pilot pressure from the pilot pump (30) by switching the switching valve (44) ;
A control operation position (44a) for connecting a pump port (p) communicating with the pilot pump (30) and a valve port (v) communicating with the control valve (22) to the switching valve (44) ; together and a manual operation position (44b) for connecting the valve port and the pilot port (r) in communication with the pilot valve (32b) (v), the return spring biasing said to manual operation position (44b) ( and 46), and an operating oil passage acting in a direction to switch to manual operation position (44b) (47) of the valve port (v) the resulting pressure the switching valve (44),
The switching valve (44) is configured to be alternately and quickly switched between the manual operation position (44b) and the control operation position (44a) by a command from the control means (40), and the manual operation is performed. A pilot pressure on the valve port (v) side of the switching valve (44) generated by operation from the system and a pilot pressure on the valve port (v) side of the switching valve (44) generated by control from the control operation system. A hydraulic control device for a working machine, comprising a pilot pressure adjusting mechanism (E) for supplying a higher pressure to the control valve (22) . The artificial control system is constituted by a device capable of operating the arm control valve (22) with a pilot pressure for the arm discharging operation from the pilot valve (32b) that is manually operated,
The operation of the excavating work device (3) is controlled based on the detection information of the position sensor for detecting the position of the bucket (6), so as to prevent interference between the bucket (6) and the operating unit (15). Then, when the bucket (6) approaches the restraint surface (A1) set near the operating portion with the upward movement of the boom (4), the bucket (6) is moved from the restraint surface (A1) to the operating portion (15). The control operation system is constituted by automatically operating the arm control valve (22) so as to drive the arm (5) to the earth discharging side so as to avoid the approach of (6). 2. The hydraulic control device for a working machine according to claim 1.

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