JP2697473B2 - Construction equipment merging equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit merging apparatus mainly mounted on a construction machine such as a crawler type hydraulic excavator or a work vehicle.

[0002]

2. Description of the Related Art FIG. 4 is a main part circuit diagram of a crawler type hydraulic shovel equipped with a conventional merging device. In the figure, 1 is a work attachment mounted on the front part of the excavator, 2 is a boom of the work attachment 1,
3 is an arm, 4 is a bucket, 5 is a boom cylinder, 6 is an arm cylinder, 7 is a bucket cylinder, 8L and 8R.
Is a left and right traveling motor, 9 is a turning motor, 10L and 10
R is a traveling motor control switching valve (hereinafter referred to as traveling valve);
Reference numeral 11 denotes a boom cylinder control pilot switching valve (hereinafter, referred to as a boom cylinder control valve).
Boom valve), 12 is a pilot switching valve for arm cylinder control (hereinafter, arm valve), 13 is a pilot switching valve for bucket cylinder control (hereinafter, bucket valve), 14 is a pilot switching valve for swing motor control (hereinafter, pilot valve). , A swivel valve), 15 to 19 are the respective valves 10 described above.
A sub-valve connected to L, 10R, 11, 12, 13;
Reference numeral 20 denotes a straight traveling valve, reference numerals 21 and 22 denote pilot on / off valves (hereinafter, referred to as on / off valves), reference numerals 25 and 26 denote first and second pumps, respectively, reference numeral 27 denotes a pilot pump, and reference numeral 28
Reference numerals 29 and 29 denote a center bypass oil passage, 30 a bucket remote control valve, 31 an arm remote control valve, 32 a turning remote control valve, and 33 a boom remote control valve. The symbols ey, rolo, ..., and cheeche indicate the connections of the pilot pipelines, respectively. The remote control valves 30, ...,
Reference numeral 33 denotes a total of four independent lamps, which are shown for convenience of explanation. Actually, a pair of left and right remote control valves can be operated in the cross direction.

In the prior art hydraulic circuit shown in FIG. 4, various hydraulic actuators (8L, 8L,
6, 9, 8R, 5, 7) are divided into two groups A and B, each of which is driven by a first pump 25 and a second pump 26, respectively, and various hydraulic actuator control switching valves (10L, 12, 14, 10R, 11, 13) are provided with sub-valves (15, 18, 16, 17, 19) for passing or shutting off the pilot primary pressure in conjunction with the switching valve (excluding the swivel valve 14). Concatenate,
Also, the center bypass oil passages 2 of the groups A and B respectively
On-off valves 21 and 22 are arranged at the outlets of 8 and 29,
The traveling straight valve 2 is provided on the discharge side of the pump 25 and the second pump 26.
0 is arranged. By operating the remote control valves 30 to 33 when the hydraulic excavator performs work, the bucket 4, the arm 3, the swing of the upper swing body (not shown), and the boom 2 can be moved. When the excavator travels, the travel valves 10L, 10R
Operate. When the travel valves 10L and 10R are simultaneously operated and one of the other actuators is operated, the travel straight traveling valve 20 is switched from the oil passage position R to a straight traveling oil passage position nu. Thus, even if the work attachment and the turning are moved while the excavator is traveling, the excavator can travel straight without meandering.

In the hydraulic circuit shown in FIG. 4, an interlock valve 23 is connected between an upstream port of the sub-valve 19 of the bucket valve 13 and a pilot pump 27. The interlock valve 23 switches from the oil passage position to the oil passage position e when the pilot secondary pressure acting on the pilot port 34 becomes equal to or higher than a predetermined pressure P by the spring force of the built-in spring 24. It is set as follows.
Therefore, when the hydraulic excavator wants to increase the operating speed of the bucket cylinder 7 and perform heavy excavation (including discharge),
The operation lever 35 of the bucket remote control valve 30 is tilted greatly in the rightward or leftward direction from the neutral position. In this case, the pilot secondary pressure acting on the left and right pilot ports of the bucket valve 13 becomes higher than the set pressure P.
Therefore, the high pilot secondary pressure is applied to the shuttle valve 3
6 acts on the pilot port 34, the interlock valve 23 is switched from the oil passage position to the oil passage position e.
The pilot primary pressure from the pilot pump 27 is determined by the position of the interlock valve 23, the line 37, the check valve 38,
Pipe line 39, (at this time, the sub-valve 19 is in the shut-off oil passage position because the bucket valve 13 is being switched, the oil passage 40, the opening oil passage position of the sub-valve 17 of the boom valve 11, the oil passage 41, the pipe It acts on the port 45 of the straight travel valve 20 via the paths 42 and 43 and the shuttle valve 44. The traveling straight traveling valve 20 switches from the oil passage position to the straight traveling oil passage position (nu). The pressure oil from the first pump 25 is supplied to the pipeline 46, the null position of the straight traveling valve 20, the oil paths 47, 48, the check valve 49, the oil paths 50, 51, 52, the check valve 53, the oil path 54, It is supplied to the bucket cylinder 7 via the switching position 13 and the pipeline 55 or 56. At the same time, the pressure oil from the second pump 26 is supplied to the pipelines 57 and 58, the null position of the straight traveling valve 20, the oil passage 59, the neutral position of the traveling valve 10R, the oil passage 6
0, 61, the check valve 62, the oil passage 63, and the oil passage 51
To join. Therefore, the bucket cylinder 7
Since the discharge pressure oils of the pump 25 and the second pump 26 are supplied and combined, heavy excavation can be performed by increasing the rotation speed of the bucket 4.

[0005]

In the prior art merging apparatus, the operating angle of the operating lever of the bucket remote control valve is increased so that the pilot secondary pressure derived from the bucket remote control valve exceeds the set pressure P. At the time of merging with the bucket cylinder. For this reason, the operation lever must be largely operated at the time of merging, so that the operation control range of the operation lever at that time becomes narrow, and responsiveness and inching performance are poor. In addition, since the interlock valve for controlling the merging is controlled by the pilot secondary pressure, the total length of the pilot pipe becomes very long and occupies a considerable amount of space inside the vehicle body, which hinders miniaturization of the vehicle body. An object of the present invention is to provide a merging device that can solve the above problems.

[0006]

In the merging apparatus for construction machines according to the present invention, operating state detecting means for various hydraulic actuators are provided, and a controller controls a traveling straight valve and an on-off valve based on a detection signal from the operating state detecting means. When the required hydraulic actuator is independently operated, the controller outputs a straight-travel position command signal to the traveling straight-travel valve, and the on-off valve on the side where the required hydraulic actuator is not disposed. Output the closing position command signal to the

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing a merging device according to a first embodiment of the present invention. In the figure, the same reference numerals are given to components using the same components as the conventional technology. 10'L,
10'R is a left and right traveling valve, 11 'is a boom valve, 12' is an arm valve, 13 'is a bucket valve, 68 is a controller,
Reference numerals 70 and 71 denote limit switches for detecting the operation states of the traveling valves 10'L and 10'R, respectively, and reference numerals 73, 74 and 75 denote electromagnetic proportional pressure reducing valves which are electro-hydraulic converters.

Next, the structure of the merging apparatus according to the first embodiment of the present invention will be described with reference to FIG. In the merging apparatus according to the first embodiment of the present invention, the potentiometers 64, 65, 66, and 67 are provided on the remote control valves 30 ', 31', 32 ', and 33' for the bucket, the arm, the swivel, and the boom, respectively. Operation state detection signals from the potentiometers 64 to 67 are input to the controller 68, and the controller 68 makes a determination based on the input operation state detection signals.
From the controller 68, the electromagnetic proportional pressure reducing valves 73 and 7, respectively.
4 and 75, the straight traveling valve 20 and the on-off valves 21 and
2 to output a command signal.

Next, the operation of the merging apparatus according to the first embodiment of the present invention will be described. First, as a first case, a case where only the bucket 4 is operated alone without traveling will be described. Potentiometer 6 for bucket remote control valve 30 '
4 is input to the controller 68. The controller 68 makes a judgment based on the operation state detection signal, and sends a straight-running position command signal to the running straight-running valve 20 via the electromagnetic proportional pressure reducing valve 73 and the bucket valve 13 '.
A closing position command signal is output via the electromagnetic proportional pressure reducing valve 74 to the on-off valve 21 on the group A side where is not disposed. At the same time as the straight travel valve 20 switches to the null position, the on-off valve 21 switches to the closed position. First pump 25
From the pipe 46, the null position of the straight travel valve 20, the oil paths 47 and 48, the check valve 49, and the oil paths 50, 51 and 5.
2, the check valve 53, the oil passage 54, the switching position of the bucket valve 13 ', the pipe 55 or 56, and the bucket cylinder 7
Supplied to At the same time, the pressure oil from the second pump 26 is supplied to the pipeline 57 (the pressure oil does not flow to the oil passage 72 because the on-off valve 21 is switched to the closed position at this time).
8. Null position of the straight travel valve 20, oil passage 59, travel valve 10 '
R passes through the neutral position, the oil passages 60 and 61, the check valve 62, and the oil passage 63, and merges with the oil passage 51. Therefore, since the discharge pressure oils of the first pump 25 and the second pump 26 are supplied to the bucket cylinder 7 in a combined manner, heavy excavation can be performed by increasing the rotation speed of the bucket 4.

Next, as a second case, traveling and bucket 4
The case where the simultaneous operation is performed will be described. The operation state detection signals from the limit switches 70 and 71 and the operation state detection signal from the potentiometer 64 of the bucket remote control valve 30 ′ are input to the controller 68. The controller 68 makes a determination based on the two operation state detection signals,
A switching command signal is output to the straight traveling valve 20. When the straight travel valve 20 is switched to the null position, the travel valve 10 '
L, 10'R and the bucket valve 13 'are also switched from the neutral position to the switching position. The pressure oil from the first pump 25 is supplied to the pipeline 46, the null position of the straight travel valve 20, the oil passages 47 and 4.
8, the check valve 49, the oil paths 50, 51, 52, the check valve 53, the oil path 54, the yaw position or the position of the bucket valve 13 ', and the pipe 55 or 56 are supplied to the bucket cylinder 7. At the same time, the pressure oil from the second pump 26 passes through the pipe 57, one of which is supplied to the left running motor 8L through the switching position of the pipe 72 and the running valve 10'L, and the other branches in the pipe 57. Then, the oil is supplied to the traveling motor 8R through the oil passage 58, the null position of the straight traveling valve 20, the oil passage 59, and the switching position of the traveling valve 10'R. Since the hydraulic oil from the second pump 26 is supplied to the left and right traveling motors 8L and 8R in parallel, the hydraulic shovel goes straight, and the bucket cylinder 7 can be operated by the hydraulic oil from the first pump 25. . In this case, since no merging is performed with the bucket cylinder, the bucket 4 rotates at a low speed.

FIG. 2 is a circuit diagram showing a merging device according to a second embodiment of the present invention. In the figure, components using the same components as those of the first embodiment are denoted by the same reference numerals. Reference numeral 20 'denotes an electromagnetic traveling linear valve (hereinafter referred to as an electromagnetic linear valve), and reference numerals 21' and 22 'denote electromagnetic opening / closing valves. In the merging apparatus of the second embodiment, each remote control valve 30 ',.
Operation state detection signals from the potentiometers 64,..., And 67 are input to the controller 68, and the controller 68 makes a determination based on the input operation state detection signals. A command signal is output to the electromagnetic on-off valves 21 'and 22'. That is, the merging apparatus of the second embodiment is different from the straight traveling valve 20 and the on-off valve 21 shown in FIG.
22 is an electromagnetic straight valve 20 'and an electromagnetic on-off valve 2 respectively.
1 'and 22'. Therefore, the operation and function of the merging device of the second embodiment are the same as those of the merging device of the first embodiment in FIG.

FIG. 3 is a circuit diagram showing a merging device according to a third embodiment of the present invention. In the figure, components using the same components as those of the first embodiment are denoted by the same reference numerals. Reference numerals 30, 31, 32, and 33 denote remote control valves for bucket, arm, swing, and boom, respectively.
8, 79 are pressure sensors, 80, 81, 82, 8 respectively.
Reference numeral 3 denotes a shuttle valve for selecting a high pressure of the pilot secondary pressure.
In the merging apparatus of the third embodiment, potentiometers 64, 67 in FIG. 1 are replaced by pressure sensors 80, 83. The operation and function of the merging device of the third embodiment are the same as those of the merging device of the first embodiment in FIG.

[0013]

According to the prior art merging apparatus, when the operation angle of the operation lever of the bucket remote control valve is increased and the pilot secondary pressure derived from the bucket remote control valve exceeds the set pressure P, the bucket is closed. Merging to the cylinder is performed. For this reason, the operation lever must be largely operated at the time of merging, so that the operation control range of the operation lever at that time becomes narrow, and responsiveness and inching performance are poor. In addition, since the interlock valve for controlling the merging is controlled by the pilot secondary pressure, the total length of the pilot pipe becomes very long and occupies a considerable amount of space inside the vehicle body, which hinders miniaturization of the vehicle body. However, the merging apparatus of the present invention is provided with operation state detecting means for various hydraulic actuators, and outputs a command signal from the controller to the traveling straight valve and the on-off valve based on a detection signal from the operation state detecting means. Then, when the operation lever of the bucket remote control valve is operated with a normal operation angle amount to operate a required hydraulic actuator such as a bucket cylinder, a detection signal from the bucket cylinder operation state detecting means is input to the controller. The controller makes a determination based on the operation state detection signal, outputs a straight travel position command signal to the traveling straight travel valve, and outputs a close position command signal to the on-off valves of the group on which the bucket valve is not arranged. . Since the traveling straight valve and the open / close valve are switched, the discharge pressure oil of the first pump and the second pump is supplied to the bucket cylinder in a merged manner. Therefore, the rotating speed of the bucket can be increased to perform heavy excavation. Further, the interlock valve in the conventional merging device is not required, and the length of the piping can be reduced, so that the body can be downsized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a merging device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a merging device according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a merging device according to a third embodiment of the present invention.

FIG. 4 is a main part circuit diagram of a crawler type hydraulic excavator equipped with a conventional merging device.

[Explanation of symbols]

4 Bucket 7 Bucket Cylinder 8L, 8R Traveling Motor 10L, 10R, 10'L, 10'R Traveling Motor Control Switching Valve 13, 13 'Bucket Cylinder Control Pilot Switching Valve 20 Traveling Straight Valve 20' Electromagnetic Traveling Straight Valve 21, 22 Pilot on-off valve 21 ', 22' Electromagnetic on-off valve 25, 26 First and second pump 27 Pilot pump 30, 30 'Bucket remote control valve 64, ..., 67 Potentiometer 68 Controller 70, 71 Limit switch 73, 74, 75 Electromagnetic proportional pressure reducing valve 76, ~, 79 Pressure sensor

Claims (1)

(57) [Claims] 1. A work attachment in which a boom, an arm, and a bucket are sequentially connected is mounted on a front portion of a construction machine, and various hydraulic actuators mounted on the construction machine are divided into two groups A and B. And the second
It is driven by a pump, and the above groups A and B
When an on-off valve is disposed at the outlet of the center bypass oil passage, and a traveling straight valve is disposed on the discharge side of the first and second pumps, when only a required hydraulic actuator among the various hydraulic actuators is operated alone. A merging device for merging and supplying the hydraulic oil from the first and second pumps to the hydraulic actuator, wherein operation state detecting means for various hydraulic actuators is provided, and detection from the operation state detecting means is performed. The controller outputs a command signal to the traveling straight valve and the on-off valve based on the means, and outputs a straight position command signal to the traveling straight valve from the controller when the required hydraulic actuator is operated alone. Output the closing position command signal to the open / close valve on the side where no hydraulic actuator is disposed. Confluence device for a construction machine to be.