JP2950816B1 - Hydraulic control circuit of work machine - Google Patents

Abstract

Abstract: [PROBLEMS] When a working unit approaches a cab during work,
Work can be continued while avoiding the working unit from interfering with the cab. SOLUTION: Boom reduction side, boom extension side, offset reduction side pilot valve 21A, 21B, 22
A so that the pilot pressure oil output from A can also be supplied to the stick-side reduction-side oil passage via the switching valve 33, and when the working unit reaches the interference prevention area, the stick 8
By automatically turning off, the boom raising, boom lowering, and left offset operations can be continued while avoiding the interference prevention area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a hydraulic control circuit for a working machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art In general, some working machines such as hydraulic shovels are provided with an offset-type working unit that swings left and right. In such a case, when the working unit is moved, the working unit is moved. There is a risk of contact (interference) with the driver's seat. In such a case, care must be taken to avoid contact between the working unit and the driver's seat. Therefore, conventionally, a posture detecting means for detecting the posture of the working unit, and a control unit for determining whether the working unit is approaching within a predetermined range of the driver's seat part based on a detection signal from the posture detecting means, If it is determined that the working unit is approaching a predetermined range of the driver's seat, a control command is output from the control unit to the hydraulic circuit of the working unit hydraulic actuator, and the working unit is There is something to stop. As such a device, for example, a device as shown in FIG. 8 is known, which includes a pilot-type control valve 46 for controlling the supply of pressurized oil to a hydraulic actuator 45 such as a boom cylinder. , Pilot valve 4 that outputs pilot pressure oil based on operation of operation tool 47
Between 8A and 48B, there are provided electromagnetic proportional pressure reducing valves 49A and 49B that operate based on a command from the control unit. When the working unit is separated from the driver's seat, the solenoid proportional pressure reducing valves 49A and 49B are opened to allow the supply of pilot pressure oil to the control valve 46, while the working unit approaches the driver's seat. In this case, the electromagnetic proportional pressure reducing valves 49A and 49B are closed and the control valve 46 is closed.
The supply of pilot pressure oil to the engine is cut off, thereby stopping the working unit.

[0003]

However, as described above, when the working unit approaches the driver's seat, the conventional proportional pressure reducing valve is closed to stop the working unit. There is a problem that the working unit is stopped in the middle of the work and the working efficiency is reduced, and there is a problem to be solved by the present invention.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention has been made with the object of solving these problems. A hydraulic actuator for a working machine, comprising: a hydraulic actuator; and first and second pilot-type control valves for controlling supply of pressurized oil to the respective hydraulic actuators. Anti-interference control means for preventing the intrusion of the work unit into an interference prevention area set in advance to prevent interference between the control unit and the work unit, and at least the second hydraulic actuator is operated in the interference prevention control means. When it is determined that the working unit has reached the interference prevention area in a state in which the interference prevention area is in operation, the first hydraulic actuator is operated in a direction away from the interference prevention area to thereby prevent the interference prevention area. In order to provide a mechanism for continuing the operation of the second hydraulic actuator while avoiding the intrusion of the working unit into the inside, a pilot pressure oil for operating the second hydraulic actuator is supplied to the first hydraulic actuator by an interference prevention area. This is a hydraulic control circuit of a working machine provided with a valve means for switching so as to be able to supply also to a pilot oil passage for operating in a direction away from the working machine. By doing so, when the working unit reaches the interference prevention area during the operation of the second hydraulic actuator, the pilot pressure oil for operating the second hydraulic actuator prevents the first hydraulic actuator from interfering. Since the oil is supplied to the pilot oil passage in a direction away from the region, the operation of the second hydraulic actuator can be continued while avoiding the interference prevention region. In this, the hydraulic control circuit includes first and second near-side pilot oil passages for supplying pilot pressure oil in a direction in which the working unit approaches the interference prevention area to the first and second control valves, respectively. The first and second spaced-apart pilot oil passages for supplying pilot pressure oil in a direction away from the interference prevention area to the first and second control valves, respectively, A first and a second near side, a separation side pilot valve that respectively output pilot pressure oil to the second near side, separation side pilot oil passage, and at least a first near side pilot oil passage A hydraulic control circuit for a working machine having a control valve for opening and closing a pilot oil passage based on a command from the interference prevention control means can be provided. Further, in this device, when there are a plurality of second hydraulic actuators, the second control valve, the second near side, the separation side pilot oil passage, the second near side, the separation side pilot valve correspond to each hydraulic actuator, respectively. And a pilot pressure oil output from each of the second proximity pilot valves is combined and supplied to the valve means via a shuttle valve for selecting the high-pressure pilot pressure oil. Hydraulic control circuit of the application machine. Also in these things,
The valve means supplies the pilot pressure oil to the first separation side pilot oil passage when the pilot pressure oil is being output from the first separation side pilot valve, and the pilot pressure oil is output from the first separation side pilot valve. In a state in which the pilot pressure oil output from the second proximity side pilot valve is not supplied to the first separation side pilot oil passage, a switching valve that switches to supply the pilot pressure oil to the first separation side pilot oil passage, and a first separation side based on a command from the interference prevention control means. A hydraulic control circuit for a working machine including a control valve for opening and closing the pilot oil passage can be provided. Further, the valve means includes a control valve that outputs pilot pressure oil from the second proximity side pilot valve based on a command from the interference prevention control means, a pilot pressure oil output from the control valve, and a first separation side. A hydraulic control circuit for a working machine including a shuttle valve configured to select a high-pressure-side pressure oil from the pilot pressure oil output from the pilot valve and supply the selected high-pressure oil to the first separation-side pilot oil passage can be provided. Further, in these, the working machine includes, as a second hydraulic actuator, a boom vertical cylinder for vertically oscillating an offset type boom capable of vertically and horizontally oscillating, and an offset cylinder for horizontally oscillating. The present invention can be applied to a hydraulic shovel or the like having a stick cylinder for swinging a stick, which is swingably moved forward and backward, at a tip end of a boom as a first hydraulic actuator.

[0005]

Next, a first embodiment of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes an offset type hydraulic excavator, and the hydraulic excavator 1 is composed of components such as a lower traveling unit 2, an upper revolving unit 3, a cab 4, a working unit 5, and the like. The working part 5 includes a rear boom 6 whose base end is supported by the upper swing body 3 so as to be able to swing up and down, a front boom 7 that is supported by the tip of the rear boom 6 so as to be able to swing left and right, and a front boom 7. A stick 8 supported at the tip of the stick 8 so as to be able to swing left and right, back and forth, a bucket 9 supported at a tip of the stick 8 so as to be swingable back and forth, and a boom cylinder for swinging them (the boom of the present invention). It is composed of an up / down cylinder 10, an offset cylinder (equivalent to the boom left / right cylinder of the present invention) 11, a stick cylinder 12, a bucket cylinder 13, and the like. The basic structure of such that there is conventional, in the present embodiment, the cab 4 is provided on the left side of the upper revolving structure 3. Further, the rear boom 6 descends as the boom cylinder 10 contracts, and the boom cylinder 1
It is configured to rise as 0 expands. The front boom 7 is configured to move leftward, that is, in a direction approaching the cab 4 when the offset cylinder 11 is contracted, and move rightward when the offset cylinder 11 is extended. Furthermore, the stick 8 swings (stick-in) to the rear side of the fuselage when the stick cylinder 12 extends, and swings (stick-out) to the front side of the fuselage when the stick cylinder 12 contracts. ing.

The control of the supply of pressure oil to each of the cylinders 10 to 13 will be described with reference to a hydraulic control circuit diagram shown in FIG. 3. In FIG. 3, 14 is a main pump, 15 is a pilot pump, 16 is an oil tank, Reference numerals 17 to 20 denote control valves for boom, offset, stick, and bucket. These control valves 17 to 20 correspond to reduction-side pilot ports 17a to 20a.
And a pilot-operated three-position switching valve having extension-side pilot ports 17b to 20b.
When the pilot pressure oil is not supplied to the pilot ports 17a to 20b and 17b to 20b, the control valves 17 to 20 are in neutral positions for stopping the supply of the hydraulic oil to the corresponding cylinders 10 to 13. N, but the reduction-side pilot ports 17a-20
a is supplied with the pilot pressure oil, the cylinder 10
13 is switched to the reduced position X where the pressure oil from the main pump 14 is supplied to the reduced oil chambers of the cylinders 10 to 13 and the pilot pressure oil is supplied to the expansion side pilot ports 17b to 20b. Main pump 1 in oil chamber on extension side
4 is switched to the extension side position Y for supplying the pressure oil from.

[0007] Reference numerals 21 to 24 denote booms for supplying pilot pressure oil to pilot ports 17a to 20a and 17b to 20b of the control valves 17 to 20 based on the operation of an operating tool (not shown). These are pilot valves for offset, stick, and bucket, and each of these pilot valves 21 to 24 is composed of a reduction-side pilot valve 21A to 24A and an extension-side pilot valve 21B to 24B, respectively. When the corresponding operating tool is in a neutral state (when not operated), these pilot valves 21 to 24
Pump port 21a connected to pilot pump 15
To 24a are closed and the tank ports 21b to 24b connected to the oil tank 16 and the output ports 21c to 24c are in communication with each other. Side pilot valve 21
A to 24A or output ports 21c to 21B to 24B
24c communicates with the pump ports 21a to 24a, so that pilot pressure oil having a pressure corresponding to the operation amount of the operating tool is output from the output ports 21c to 24c. In FIG. 3, reference numerals 25, 26, and 27 denote a turning motor, a turning control valve, and a turning pilot valve for turning the upper turning body 3, respectively.

Further, a boom reduction side pilot oil passage connecting the boom reduction side pilot valve 21A and the boom control valve reduction side pilot port 17a, a boom extension side pilot valve 21B and a boom control valve extension side pilot. Port 17b
, A boom extension side pilot oil path, an offset reduction side pilot oil path connecting the offset reduction pilot valve 22A and the offset control valve reduction side pilot port 18a, a stick extension side pilot valve 23B and a stick. Each of the pilot oil passages of the stick extension pilot oil passage connecting the control valve extension side pilot port 19b has a boom reduction side, a boom extension side, an offset reduction side, and a stick extension side. Although the proportional pressure reducing valves 28, 29, 30, 31 are provided, these electromagnetic proportional pressure reducing valves 28, 29, 30, 31 are the same, and therefore, the electromagnetic proportional pressure reducing valve 28 on the boom reduction side is taken as an example. To explain, the electromagnetic proportional pressure reducing valve 28 includes first to third ports 28a, 8b, 28c, and the solenoid 2
8d, but the first port 28a is
The second port 28b is connected to the output port 21c of the boom reduction-side pilot valve 21A, and the third port 28c is connected to the reduction-side pilot port 17a of the boom control valve 17. When the solenoid 28d is not excited, the electromagnetic proportional pressure reducing valve 28 opens a valve path connecting the first port 28a and the third port 28c, and closes the second port 28b.
The oil from the contraction-side pilot port 17a is supplied to the oil tank 16
When the solenoid 28d is excited based on an operation command from the control unit 32, which will be described later, the output valve path connecting the second port 28b and the third port 28c is opened. Is configured. When the output valve path is opened, the pilot pressure oil from the pilot valve output port 21c is output to the control valve reduction-side pilot port 17a. It increases or decreases in response to a control command output to the excitation circuit of 28d.

On the other hand, the switching valve 33 and the stick-side reducing solenoid proportional pressure reducing valve are provided in the stick-side reducing pilot oil passage connecting the stick-side reducing pilot valve 23A and the stick control valve-side reducing pilot port 19a. 34 are provided. The switching valve 33 is a five-port two-position switching valve. The first port 33a is connected to the oil tank 16, and the second port 33b is connected to the output port 23 of the stick-side reduction pilot valve 23A.
c, a third port 33c is connected to the pilot oil passage 50 for avoidance, which will be described later, a fourth port 33d is connected to the first port 34a of the stick-side reduction proportional solenoid valve 34, and a fifth port 33
“e” is connected to the second port 34 b of the stick-side reduction valve 34. Further, the switching valve 33 is provided with a pilot port 33f,
The pilot port 33f is connected to the stick-side reduction pilot valve output port 23c and the switching valve second port 33.
The pilot pressure oil is supplied to the pilot port 33f in accordance with the output of the pilot pressure oil from the stick reducing pilot valve 23A for the stick. When the pilot pressure oil is not supplied to the pilot port 33f, the switching valve 33 closes the first port 33a by the urging force of the armature 33g, and closes the third port 33a.
The pilot pressure oil from the avoiding pilot oil passage 50 is located at the first position X where the valve passage from c to the fifth port 33e is open and the valve passage from the fourth port 33d to the second port 33b is open. Can be supplied to the electromagnetic proportional pressure reducing valve second port 34b, and oil from the electromagnetic proportional pressure reducing valve first port 34a is supplied to the oil tank 16 via the pilot valve 23A.
Can be discharged to On the other hand, when the pilot pressure oil is supplied to the pilot port 33f, the third port 33c is closed, the valve path from the second port 33b to the fifth port 33e is opened, and the fourth port 33d is connected to the first port 33a. The pilot pressure oil from the pilot valve output port 23c can be supplied to the electromagnetic proportional pressure reducing valve second port 34b and the oil from the electromagnetic proportional pressure reducing valve first port 34a Can be discharged to the oil tank 16.

The electromagnetic proportional pressure reducing valve 34 on the stick reducing side is provided with the aforementioned electromagnetic proportional pressure reducing valves 28, 29, 3.
0 and 31, the output pressure of which is increased or decreased in response to a control command from the control unit 32. The first port 34a of the valve has a fourth port 33d of the switching valve 33. The second port 34b is connected to the fifth switching port 33e, and the third port 34c is connected to the reduction-side pilot port 19a of the stick control valve 19. When the solenoid 34d is not energized, the stick-side reduction-side electromagnetic proportional pressure reducing valve 34 opens a valve path connecting the first port 34a and the third port 34c and closes the second port 34b. Thus, the oil from the reduction side pilot port 19a flows into the oil tank 16, but the second port 34b and the third port 34c are excited by energizing the solenoid 34d based on an operation command from the control unit 32. Is opened so as to open an output valve path communicating with. When the output valve path is opened, the switching valve 33 at the first position X is opened.
The pilot pressure oil from the avoidance pilot oil passage 50 via the bypass valve or the pilot pressure oil from the pilot valve 23A via the switching valve 33 at the second position Y is output to the control valve reduction side pilot port 19a. ing.

Here, the avoiding pilot oil passage 50 is used.
Are the pilot valves 21 for the boom reduction side and the boom extension side.
A, 21B and the pilot pressure oil output from the offset reducing pilot valve 22A are supplied to the switching valve 33 via the first and second shuttle valves 51, 52. That is, the boom reduction side pilot valve 21A and the boom reduction side electromagnetic proportional pressure reducing valve 2
8, a boom reduction side pilot branch oil passage 53 is branched from an intermediate portion of the oil passage connecting the boom 8 and an oil passage connecting the boom extension side pilot valve 21B and the boom extension side electromagnetic proportional pressure reducing valve 29. A boom extension-side pilot branch oil passage 54 is formed to branch off from a middle portion of the boom, and an offset passage from the middle of the oil passage connecting the offset reduction-side pilot valve 22A and the offset reduction-side electromagnetic proportional pressure reducing valve 30. The reduction-side pilot branch oil passage 55 is branched. The boom reduction side and extension side pilot branch oil passages 53 and 54 are connected to the first and second ports 51a and 51b on the inlet side of the first shuttle valve 51, respectively. The outlet port 51 c of the valve 51 is connected to the inlet first port 52 a of the second shuttle valve 52. The offset reducing pilot branch oil passage 55 is connected to the inlet second port 52b of the second shuttle valve 52, and the outlet port 52c of the second shuttle valve 52 is connected to the bypass pilot oil passage. 50. Thus, when pilot pressure oil is output from the boom reduction side or extension side pilot valve 21A or 21B, the boom reduction side or extension side pilot branch oil passage 53 or 54,
Pilot pressure oil is supplied to the avoidance pilot oil passage 50 via the first shuttle valve 51 and the second shuttle valve 52,
When the pilot pressure oil is output from the offset reduction pilot valve 22A, the pilot pressure oil flows into the avoidance pilot oil passage 50 via the offset reduction pilot branch oil passage 55 and the second shuttle valve 52. It is being supplied. When the pilot pressure oil is output from both the boom reduction side or extension side pilot valve 21A or 21B and the offset reduction side pilot valve 22A, the high pressure side pilot pressure oil is used as the avoidance pilot oil. It is supplied to the road 50.

Reference numeral 35 denotes a lock solenoid valve.
This is disposed on the primary side (upstream side) of the pilot valves 21 to 24, 27. The lock solenoid valve 35 is operated by an operator operating a lock operation tool (not shown).
Pilot pressure oil from the pilot valves 21 to 24,
It is configured to switch between a non-locking position X for outputting to the lock position 27 and a locking position Y for not outputting the pilot pressure oil.

On the other hand, the control section 32 is constituted by using a microcomputer or the like, and includes a boom angle sensor 36 for detecting a relative angle of the rear boom 6 with respect to the upper swing body 3, a front boom. 7, an offset angle sensor 37 for detecting the relative angle of the rear boom 6 with respect to the rear boom 6, a stick angle sensor 38 for detecting the relative angle of the stick 8 with respect to the front boom 7, and detection of pilot pressure oil output from the boom reduction side pilot valve 21A. Boom reduction side pressure sensor 39
A, for a boom that similarly detects that pilot pressure oil is output from each of the pilot valves 21B, 22A, 23A, and 23B for the boom extension side, offset reduction side, stick reduction side, and stick extension side. Each of the pressure sensors 39B and 40 on the extension side, the offset reduction side, the stick reduction side, and the stick extension side.
A, 41A, 41B and the like are inputted, and based on these input signals, the boom reduction side, the boom extension side, the offset reduction side, the stick reduction side, the stick extension side Each electromagnetic proportional pressure reducing valve 2
It is configured to output control commands to 8, 29, 30, 34, 31, and the like.

The offset expansion pilot oil passage connecting the offset expansion pilot valve 22B and the offset control valve expansion pilot port 18b and the bucket reduction pilot valve 24A are connected.
And a bucket reducing pilot oil passage connecting the bucket control valve reducing pilot port 20a and a bucket extending pilot oil connecting the bucket expanding pilot valve 24B and the bucket control valve extending pilot port 20b. Each pilot oil passage of the road is not provided with an electromagnetic proportional pressure reducing valve that is operated by a command from the control unit 32, and each of the pilot valves 22B, 24A, 24
The pilot pressure oil output from B is directly supplied to pilot ports 18b, 20a, and 20b. In other words, the right offset and the operation of the bucket 9 are configured to always be performed in response to the operation of the operating tool without involving the interference prevention control of the control unit 32 described later.

Next, the interference prevention control by the control unit 32 will be described with reference to a block diagram shown in FIG. 4. First, the control unit 32 controls the boom angle sensor 36, the offset angle sensor 37, and the stick angle sensor 38. Based on the detection signal, the posture calculator 42 calculates the posture (position) of the working unit 5. On the other hand, the memory 3 of the control unit 32
2a, an interference prevention area (for example, the cab 4) is set so that the working unit 5 must not approach the cab 4 any more.
(Range within 300 mm from) is stored. The control unit 32 compares the posture of the working unit 5 calculated by the posture calculator 42 with the interference prevention area H stored in the memory 32a by a comparison calculator 43, and calculates the output signal by the comparison calculator 43. Output to the device 44. Further, the output signal calculator 44 includes pressure sensors 39A, 39B, 4B, 4B for the boom reduction side, boom extension side, offset reduction side, stick reduction side, and stick extension side.
Signals from 0A, 41A and 41B are input.

The output signal calculator 44 comprises a comparison calculator 43 and pressure sensors 39A, 39B, 40A, 4A.
Electromagnetic proportional pressure reducing valves 2 for boom reduction side, boom extension side, offset reduction side, stick reduction side, stick extension side based on input signals from 1A and 41B.
The control command is output to the solenoid excitation circuits of 8, 29, 30, 34, and 31. That is, the output signal calculator 44
The pressure sensors 39A, 39B, and 40 are calculated when the operation unit 5 is calculated to be separated from the interference prevention area H by a predetermined range or more by the comparison calculator 43.
A, 41A, and 41B detect the output of the pilot pressure oil.
A solenoid excitation command is output to 0, 34 and 31 so that the output valve path is fully opened. Accordingly, when pilot pressure oil is output from each of the pilot valves 21A, 21B, 22A, and 23B on the boom reduction side, the boom extension side, the offset reduction side, and the stick extension side based on the operation of the operating tool, The pilot pressure oil is supplied to the control valve pilot ports 17a, 17b, 18 via the fully opened electromagnetic proportional pressure reducing valves 28, 29, 30, 31 as they are.
a, 19b. Further, a switching valve 33 is provided in the stick-side reduction-side pilot oil passage, and the switching valve 33 is, as described above,
In a state where the pilot pressure oil is output from the stick-side reduction pilot valve 23A based on the operation of the operating tool, the position is switched to the second position Y and the pilot valve 23A is switched.
Is supplied to the electromagnetic proportional pressure reducing valve 34. When the pilot pressure oil is output from the stick reducing pilot valve 23A based on the operation of the operating tool, the pilot pressure oil is The pressure oil is supplied to the control valve pilot port 19a via the switching valve 33 at the second position Y and the fully opened electromagnetic proportional pressure reducing valve 34. That is, when the working unit 5 is separated from the interference prevention area H by a predetermined distance or more, the working unit 5
Operates in response to the operation of the operating tool.

On the other hand, if the operation of the working unit 5 is within a predetermined range set in advance with respect to the interference prevention area H by the comparison arithmetic unit 43, the output signal arithmetic unit 4
4 is the pressure sensor 39A, 39B, 40A, 41
A, 41B, the electromagnetic proportional pressure reducing valves 28, 29, 30, 3 of the pilot oil passage in which the output of the pilot pressure oil is detected.
A solenoid excitation command is output to 4, 4 so that the output valve path is opened with the opening amount adjusted. In this case, the degree of opening of the output valve paths of the electromagnetic proportional pressure reducing valves 28, 29, 30, 34, 31 is such that the closer the working unit 5 is to the interference prevention area H, the more the electromagnetic proportional pressure reducing valves 28, 29, 30, 34, 31. The output pressure from is adjusted to be small. Thereby, based on the operation of the operating tool, the pilot valves 21A, 21B, 2B, 2B for the boom reduction side, the boom extension side, the offset reduction side, the stick reduction side, and the stick extension side are provided.
When pilot pressure oil is output from 2A, 23A, 23B, the pilot pressure oil is supplied to the electromagnetic proportional pressure reducing valves 28, 2
In the state where the pressure is reduced by 9, 30, 34, and 31, the control valve pilot ports 17a, 17b, 18a,
19a and 19b. That is, when the working unit 5 approaches within the predetermined interval of the interference prevention area H, the operations of the boom lowering and raising, the left offset, the stick-in and the stick-out are performed in a decelerated state.

On the other hand, the working unit 5 is
Is calculated to have reached the outer boundary portion of the interference prevention area H, the output signal calculator 44 calculates the electromagnetic proportional pressure reducing valves 28, 29, 30, 31, 3, based on the control command table shown in FIG.
4, a control command is output to the cab 4. In the present embodiment, two areas of the cab front side (front and right side) interference prevention area and the cab roof area interference prevention area are used as the interference prevention area H. It is set and separate control is performed in each area. FIG. 5 shows the relationship between the operation state of the operating tool and the operation command to the work unit 5,
In this case, the operation states of the boom lowering, the boom raising, the stick out, the stick in, and the left offset are the pressure sensors of the boom reduction side, the boom extension side, the stick reduction side, the stick extension side, and the offset reduction side, respectively. 39A, 39B, 41A, 41B, 40A
Is determined based on the input of the detection signal from. Also, regarding the operation commands of the boom lowering, the boom raising, the stick-out, and the left offset, the electromagnetic proportional pressure reducing valves 28, 29, and 34 on the boom reduction side, the boom extension side, the stick reduction side, and the offset reduction side, respectively. A solenoid excitation command is output to 30 to open the output valve path. Further, regarding the operation commands of the boom lowering stop, the boom raising stop, the stick-in stop, the stick-out stop, and the left offset stop, the boom reduction side, the boom extension side, the stick extension side, the stick extension side, the stick reduction side, and the offset use, respectively. Electromagnetic proportional pressure reducing valves 28, 29, 31, 3 on the reduction side
A solenoid de-energization command is output to the control units 4 and 30 to close the output valve path. Here, since the operation commands of the boom lowering, the boom raising, and the left offset are output when the operation of the boom lowering, the boom raising, and the left offset are performed, respectively, the outputs of the electromagnetic proportional pressure reducing valves 28, 29, and 30 are output. When the valve path is opened, the pilot valves 21A, 21A
The pilot pressure oil output from B and 22A is supplied to control valve pilot ports 17a, 17b and 18a. The stick-out operation command is output not only when the stick-out operation is performed but also when the stick-out operation is not performed, as described later.
When the stick-out operation is performed, that is, when the pilot pressure oil is output from the stick reduction side pilot valve 23A, the switching valve 33 is connected to the pilot pressure oil from the pilot valve 23A as described above. Is supplied to the electromagnetic proportional pressure reducing valve 34 at the second position Y, and via the switching valve 33 at the second position Y and the output valve path of the electromagnetic proportional pressure reducing valve 34, the stick reducing pilot valve Pilot pressure oil from 23A is used to reduce the pilot port 19 of the control valve for stick.
a. On the other hand, when the stick-out operation command is output in a state where the stick-out operation is not performed, as described later, the operation of the boom lowering, the boom raising, and the left offset is performed alone or in combination, and The pilot pressure oil output from any one of the reduction side, the boom extension side, and the offset reduction side pilot valve 21A, 21B, 22A is supplied to the avoidance pilot oil passage 50. At this time, the switching valve 33
Since the pilot pressure oil is not supplied from the stick reduction side pilot valve 23A for the stick, it is located at the first position X where the pressure oil in the avoidance pilot oil passage 50 is supplied to the electromagnetic proportional pressure reducing valve 34. Output from any of the boom reduction side, the boom extension side, and the offset reduction side pilot valve 21A, 21B, 22A via the switching valve 33 at the position X and the output valve path of the electromagnetic proportional pressure reducing valve 34. The pilot pressure oil is supplied to the stick control valve reduction side pilot port 19a.

First, the control performed when the working unit 5 reaches the outer boundary of the interference prevention area H in the front side interference prevention area will be described with reference to FIG. If so,
Boom lowering and stick-out operation commands are output. Thereby, the stick 8 is put out to prevent the working unit 5 from entering the inside of the interference prevention area H,
The operation of the boom lowering can be continued. in this case,
The working unit 5 descends substantially along the outer boundary of the interference prevention area H. When the stick-in operation is performed alone, a stick-in stop operation command is output, and when the left offset operation is performed alone, a left offset stop operation command is output. . This prevents the work unit 5 from automatically stopping and entering the interference prevention area H. When the operation of the boom lowering and the stick-in is performed in a combined manner, the operation command of the boom lowering and the stick-out is output. When the operation of the boom lowering and the left offset are performed in a combined manner, the boom lowering is performed. , A stick-out and left-offset operation command is output, and when the stick-in and left-offset operations are performed in a combined manner, a stick-out and left offset operation command is output. If the in and left offset operations are performed in a combined manner, operation commands for boom lowering, stick out and left offset are output. As a result, the stick 8 is put out, and the working unit 5 is moved to the position H in the interference prevention area.
The operation of lowering the boom and operating the left offset can be continued while avoiding intrusion into the vehicle. In this case, the working unit 5 moves substantially along the outer boundary of the interference prevention area H. If the operation of raising the boom is performed alone, an operation command for raising the boom and operating the stick-out is output. Thus, the operation of raising the boom can be continued while the stick 8 is moved out to prevent the working unit 5 from entering the inside of the interference prevention area H.
In this case, the working unit 5 moves substantially along the outer boundary of the interference prevention area H. When the operation of the boom raising and the stick-in is performed in a combined manner, the operation command of the boom raising and the stick-out is output,
When the operation of raising the boom and the operation of the left offset are performed in a combined manner, the operation commands of the boom raising, the stick-out and the left offset are output, and the operations of the boom raising, the stick-in and the left offset are performed in a combined manner. In this case, the boom-up, stick-out, and left-offset operation commands are output. Accordingly, the operation of the boom raising and the left offset can be continued while the stick 8 is out to prevent the working unit 5 from entering the inside of the interference prevention area H. In this case, the working unit 5 moves substantially along the outer boundary of the interference prevention area H. Although not shown in FIG. 5 in the control of the front / side portion interference prevention area, when the stick-out operation is performed alone or in combination with each of the above-described operations (stick-out operation and stick-in operation). Is performed simultaneously with
Of course) is output alone or together with each of the above-mentioned operation commands.

Next, the control when the working unit 5 reaches the outer boundary of the interference prevention area H in the roof interference prevention area will be described. When the boom lowering operation is performed alone, When a boom lowering stop operation command is output and a stick-in operation is performed alone, a stick-in stop operation command is output, and when a stick-out operation is performed alone, a stick-out operation is performed. A stop operation command is output. This prevents the work unit 5 from automatically stopping and entering the interference prevention area H. As for the operation command when the operation of lowering the boom is performed alone, the angle of the stick 8 is the elevation angle as in the case where the operation of lowering the boom and the operation of the stick-in described below are performed in combination. Sometimes, it can be set to output a boom lowering and stick-out operation command. In such a case, the stick 8 is moved out to prevent the working unit 5 from entering the inside of the interference prevention area H,
The operation of the boom lowering can be continued. If the operation of boom lowering and stick-in operation is performed in a combined manner, an operation command for boom lowering and stick-out or an operating command for boom lowering stop and stick-in stopping is output according to the posture of the stick 8. That is,
As shown in FIG. 6A, when the angle of the stick 8 is an elevation angle with respect to the vertical line L passing through the pivot point of the stick 8, an operation command for boom lowering and stick-out is output. The boom lowering operation can be continued while the working unit 5 is turned out to prevent the working unit 5 from entering the interference prevention area H. In this case, the working unit 5 moves along the outer boundary of the interference prevention area H. As shown in FIG. 6B, when the angle of the stick 8 is a depression angle with respect to the vertical line L passing through the pivot point of the stick 8, an operation command for stopping the boom descent and stopping the stick-in is output. . This prevents the work unit 5 from automatically stopping and entering the interference prevention area H. When the operation of the boom lowering and the stick-out is performed in a combined manner, an operation command for stopping the boom lowering and stopping the stick-out is output. This prevents the work unit 5 from automatically stopping and entering the interference prevention area H. Although not shown in FIG. 5 in the control of the roof part interference prevention area, when a boom raising operation is performed, a boom raising operation command is output and a left offset operation is performed. In this case, the operation command of the left offset is output. However, when the operation of the boom raising and the left offset is performed in combination with each of the above-described operations (the operation of the boom raising and the operation of the boom lowering are performed simultaneously. Is of course not present), an operation command for boom raising and left offset is output together with the above operations. In any of the control of the front side interference prevention region and the roof portion interference prevention region, the right offset and the operation of the bucket 9 are as follows.
As described above, since it is not involved in the interference prevention control, an operation corresponding to the operation of the operation tool is performed.

In the configuration described above, the working unit 5 operates in response to the operation of the operating tool when the working unit 5 is separated from the interference prevention area H by a predetermined distance or more as described above. Automatically decelerates when approaching within a predetermined interval of the area H, and automatically stops when the vehicle reaches the interference prevention area H, according to the operation state of the operating tool and the posture of the working unit 5. Or approaching the interference prevention area of the second hydraulic actuator, which is the lowering and raising of the boom 3 and the left offset, while avoiding that the stick 8 is automatically out and the working unit 5 enters the interference prevention area H. Side operation can be continued.

As a result, for example, when the working unit 5 reaches the interference prevention area H during the operation of lowering the boom, the stick 8 is automatically out and the boom 6 is moved while avoiding the interference prevention area H. Since the lowering operation is continued, the work does not stop as in the related art, and the work efficiency is improved.

In addition, since the work can be continued while avoiding the interference prevention area H only by automatically ejecting the stick 8, the stick is one of the hydraulic actuators provided in the working unit 5 for the stick. It is only necessary to incorporate a circuit for automatically reducing the size of the cylinder into only the circuit of the cylinder 12, so that the circuit can be simplified and the cost can be reduced. Further, since only the stick 8 is automatically performed, the interference avoiding operation is simplified, and the operator can easily recognize the operation.

Further, the pilot pressure oil supplied to the stick control valve reduction side pilot port 19a for automatically releasing the stick 8 is as follows:
Since the pilot pressure oil is output from each of the pilot valves 21A, 21B, 22A on the boom reduction side, boom extension side, and offset reduction side in accordance with the operation of the boom lowering, the boom raising, and the left offset, the stick pressure is reduced. Even if a malfunction occurs such that the stick 8 comes out without permission due to malfunction of the side electromagnetic proportional pressure reducing valve 34 due to a failure or the like, the boom lowering, boom raising, left There is an advantage that if the operation of the offset is stopped, the stick 8 can be stopped without permission.

The present invention is, of course, not limited to the first embodiment. In the first embodiment, the switching valve 33 supplies the pilot pressure oil to the pilot port 33f. Thus, it is configured to switch from the first position X to the second position Y, but this switching valve is an electromagnetic valve that switches from the first position to the second position based on a solenoid excitation command from the control unit, Then, when the detection signal from the stick-side reduction-side pressure sensor is input to the control unit,
The control unit may output a solenoid excitation command to switch the switching valve to the second position.

Further, in order to be able to supply the pilot pressure oil in the avoidance pilot oil passage 50 to the stick control valve reduction side pilot port 19a, a configuration as shown in FIG. 7 may be adopted. . That is, in this embodiment, the stick-side oil passage connecting the stick-side pilot valve 23A and the stick control valve-side pilot port 19a is equivalent to the switching valve of the first embodiment. Is provided, and a stick-side reduction proportional electromagnetic pressure reducing valve 56 that operates based on a control command from the control unit 32 and a third shuttle valve 57 are provided. The third shuttle valve 57 is connected to the first port 5 on the inlet side.
7a is connected to the third port (output port) 56c of the stick reducing side electromagnetic proportional pressure reducing valve 56, and the inlet side second port 57b is connected to the third port (output port) of the avoiding electromagnetic proportional pressure reducing valve 58 described later. ) 58c, the outlet side port 57c is connected to the stick control valve reduction side pilot port 19a, and the high pressure side of the pilot pressure oil inputted from the inlet side first and second ports 57a, 57b. Is selected and output from the outlet port 57c. The avoiding electromagnetic proportional pressure reducing valve 58 is operated based on a control command from the control unit 32, and a first port (input port) 58 a of this valve is connected to the avoiding pilot oil passage 50. ing. When the stick-out operation is performed, the control unit 32 outputs an output valve passage that connects the first port (input port) 56a and the third port 56c to the stick reduction-side electromagnetic proportional pressure reducing valve 56. , A control command is output to fully open the first port 58 a and the third port 58
The control command is output so as to fully close the output valve path communicating with the control valve c. As a result, the pilot pressure oil from the stick reducing side electromagnetic proportional pressure reducing valve 56 is selected by the third shuttle valve 57, and the pilot pressure oil is supplied to the stick control valve reducing side pilot port 19a. When a stick-out operation is performed, the stick-out operation is performed in response to the operation. On the other hand, when it is determined that the working unit 5 has reached the outer boundary of the interference prevention area H in a state where the stick-out operation has not been performed, the control unit 32 causes the stick-side reduction-side electromagnetic proportional pressure reducing valve 56 to operate. On the other hand, a control command is output to completely close the output valve path, while a control command is output to the avoidance electromagnetic proportional pressure reducing valve 58 to open the output valve path.
As a result, the pilot pressure oil from the avoidance electromagnetic proportional pressure reducing valve 58 is selected by the third shuttle valve 57, and the pilot pressure oil is supplied to the stick control valve reduction side pilot port 19a. Thus,
When the working unit 5 reaches the outer boundary of the interference prevention area H in a state where the stick-out operation has not been performed,
The pilot pressure oil from the avoiding pilot oil passage 50 is supplied to the stick control valve reduction side pilot port 19a via the avoiding electromagnetic proportional pressure reducing valve 58, and the automatic operation of the stick-out is performed. . In the second embodiment, the same (same) components as those in the first embodiment are denoted by the same reference numerals.

[Brief description of the drawings]

FIG. 1 is a side view of a hydraulic excavator.

FIG. 2 is a plan view of the hydraulic excavator showing a state where the front boom is swung right and left.

FIG. 3 is a hydraulic control circuit diagram of a hydraulic actuator.

FIG. 4 is a block diagram illustrating a control procedure of interference prevention control.

FIG. 5 is a table showing a control command for interference prevention control.

FIG. 6A shows a case where the stick angle is an elevation angle.
(B) is a diagram showing a case where the angle of the stick is a depression angle.

FIG. 7 is a hydraulic control circuit diagram showing a second embodiment.

FIG. 8 is a hydraulic control circuit diagram of a hydraulic actuator showing a conventional example.

[Explanation of symbols]

 Reference Signs List 4 Cab 5 Working part 10 Boom cylinder 11 Offset cylinder 12 Stick cylinder 17 Boom control valve 18 Offset control valve 19 Stick control valve 21A Boom reduction side pilot valve 21B Boom extension side pilot valve 22A Offset reduction Side pilot valve 23A Stick reduction pilot valve 23B Stick extension pilot valve 28 Boom reduction electromagnetic proportional pressure reducing valve 29 Boom extension electromagnetic proportional pressure reducing valve 30 Offset reduction electromagnetic proportional pressure reducing valve 31 Stick expansion electromagnetic Proportional pressure reducing valve 32 Control unit 33 Switching valve 34 Reduction-side electromagnetic proportional pressure reducing valve for stick 50 Pilot oil path for avoidance 51 First shuttle valve 52 Second shuttle valve H Interference prevention Area

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02F 3/43 E02F 9/24 F15B 11/08

Claims (6)

(57) [Claims] A first and a second hydraulic actuator for operating a working unit, and a first and a second pilot-type control valve for controlling hydraulic oil supply to each hydraulic actuator, respectively. An oil pressure control circuit for a working machine, comprising: an interference prevention control means for preventing an intrusion of the working unit into an interference prevention area set in advance to prevent interference between the working machine body and the working unit. The interference prevention control means, when it is determined that the working unit has reached the interference prevention area in a state where at least the second hydraulic actuator is operating, moving the first hydraulic actuator away from the interference prevention area When providing a mechanism for continuing the operation of the second hydraulic actuator while avoiding intrusion of the working unit into the interference prevention area by operating the second hydraulic actuator, Hydraulic control circuit of a working machine provided with valve means for switching so that pilot pressure oil for operating a hydraulic actuator can also be supplied to a pilot oil path for operating the first hydraulic actuator in a direction away from the interference prevention area. . 2. The first and second control valves according to claim 1, wherein the hydraulic control circuit supplies the first and second control valves with pilot pressure oil in a direction in which the working unit approaches the interference prevention area.
A second pilot oil passage for supplying pilot pressure oil in a direction in which the working unit moves away from the interference prevention area to the first and second control valves, A first and a second near side, a separation side pilot valve that respectively output pilot pressure oil to the pilot oil passage on the separation side, based on the operation of the second operation tool, and A hydraulic control circuit for a working machine, wherein a control valve for opening and closing the pilot oil passage based on a command from the interference prevention control means is provided at least in the first near-side pilot oil passage. 3. The hydraulic control system according to claim 2, wherein when the plurality of hydraulic actuators are plural, the second control valve, the second proximal side, the separated pilot oil passage, the second proximal side, and the separated pilot valve are each hydraulic actuator. The pilot pressure oil output from each of the second proximity pilot valves is supplied to the valve means by merging via a shuttle valve that selects the pilot pressure oil on the high pressure side. Hydraulic control circuit for working machine with a configuration. 4. The valve device according to claim 2, wherein the valve means comprises:
In a state where the pilot pressure oil is output from the first separation side pilot valve, the pilot pressure oil is supplied to the first separation side pilot oil passage, and in a state where the pilot pressure oil is not output from the first separation side pilot valve. A switching valve for switching the pilot pressure oil output from the second proximity side pilot valve to be supplied to the first separation side pilot oil passage, and the first separation side pilot oil passage based on a command from the interference prevention control means. Hydraulic control circuit for working machine, consisting of a control valve that opens and closes. 5. The valve according to claim 2, wherein the valve means comprises:
A control valve that outputs pilot pressure oil from the second proximity pilot valve based on a command from the interference prevention control means, a pilot pressure oil output from the control valve, and a pilot output from the first separation side pilot valve. A hydraulic control circuit for a working machine comprising a shuttle valve that selects a high-pressure side pressure oil from the pressure oil and supplies the selected high-pressure oil to a first separation-side pilot oil passage. 6. The working machine according to claim 1, wherein the working machine includes a boom vertical cylinder for vertically swinging an offset type boom that can swing vertically and horizontally as a second hydraulic actuator. , An offset cylinder for swinging left and right, and a hydraulic excavator having a stick cylinder for swinging back and forth as a first hydraulic actuator a stick supported to be able to swing back and forth at the end of the boom. Hydraulic control circuit of working machine.