JP2003090303A - Hydraulic circuit of working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that oil passages are branched in a conventional hydraulic circuit, a pilot oil passage control valve is provided between the oil passages, and the piping becomes complicated and the cost is increased. SOLUTION: The hydraulic pressure feed control of a plurality of hydraulic actuators is performed by each control valve, each control valve is switched by a pilot operating means and other means, an unload oil passage switching valve 35 is provided between an unload oil passage leading to an oil tank, oil passages 36 and 40 to feed the hydraulic pressure to a control valve of each hydraulic actuator, and a hydraulic pump 31, control valves 50 and 60 to simultaneously switch ON-OFF output ports of two systems are provided on a discharge oil passage of the hydraulic pump, the output port of one system is connected to valves 56, 57, 58 and 59 to switch the feed of the pilot hydraulic oil to the control valves, and the other system is connected to a pilot operation unit 35a of the unload oil passage switching valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique of a hydraulic circuit of a hydraulic work machine such as an excavation and turning work vehicle. More specifically, the present invention relates to a technique for simplifying a hydraulic piping configuration of a pilot valve and a pilot oil passage.

[0002]

2. Description of the Related Art A boom, which is a working machine for excavation and turning work vehicles,
An operating lever is provided in the driver's seat so that each hydraulic actuator can be operated in order to rotate, rotate, or travel the arm and bucket. The operation lever is configured to directly operate the spool of the switching valve or operate the pilot valve to switch the switching valve. Conventionally, in a circuit for supplying pilot pressure oil to the pilot valve, as shown in FIG. 7, one end of an on-off valve oil passage 102 is connected to a pump 101 and the other end is connected to a pump port of a safety valve 103. The tank port of the safety valve 103 is connected to the oil tank, and the safety valve 10
When 3 is turned off, pressure oil from the pump is flowing into the oil tank. Then, one end of the pilot oil passage 104 is connected to the output port of the safety valve 103. A branch point is provided at the other end of the pilot oil passage 104, and one ends of the pilot oil passage 105 and the branched pilot oil passage 106 are connected to each other. A branch point is also provided at the other end of the pilot oil passage 105, and the first pilot oil passage 107 is provided.
And the second pilot oil passage 108 are connected, and the first pilot oil passage 107 and the second pilot oil passage 108 are connected.
Are connected to the pilot valves 109, 109, respectively. With such a circuit, the technique of supplying pressure oil from the pump 101 to the pilot valves 109, 109 is
It is known from Japanese Patent No. 3153118.

[0003]

However, in the conventional hydraulic circuit, from the hydraulic pump 101 to the safety valve 103.
Pipe 102 to the safety valve 103, pipe 104 from the safety valve 103 to the branch, and two pipes 105 and 10 from the branch
6 、 Pilot valve 1 branched from one oil passage
Since it is connected to the pipes 107 and 108 up to 09.109, there are problems that the number of pipes is large and complicated, the cost is high, and the number of assembling steps is increased.

[0004]

The problem to be solved by the present invention is as described above, and the means for solving this problem will be described below.

That is, according to the first aspect of the present invention, the hydraulic pressure supply control of the plurality of hydraulic actuators is performed by each corresponding control valve, and the switching operation of each control valve is performed by the pilot operating means, the manual operating means or the electric operating means. In a working machine in which both operating means such as a mechanical operating means and the like are used, an unloading oil passage leading to an oil tank, an oil passage supplying the control valve of each hydraulic actuator, and a hydraulic pressure supply source. An unloading oil passage switching valve is installed between and, and an opening / closing valve for switching on / off two output ports at the same time is provided in the discharge oil passage of the hydraulic pump. Connected to the valve for switching the supply of pilot pressure oil to the control valve,
The other system is connected to the pilot operation part of the unload oil passage switching valve.

According to a second aspect of the present invention, the hydraulic pressure supply control of the plurality of hydraulic actuators is performed by each corresponding control valve, and the switching operation of each control valve is performed by the plurality of pilot operating means and the manual operating means or the electric operating means. In a work machine in which an operating means such as a dynamic operating means is used, an unloading oil passage to an oil tank, an oil passage to supply to a control valve of each hydraulic actuator, and a hydraulic supply source are provided. In addition to providing an unloading oil passage switching valve between the two, an opening / closing valve for switching on or off at least three output ports of the hydraulic pump at the same time is provided in the discharge oil passage of the hydraulic pump. Connect the port to the valve that switches the supply of pilot pressure oil to the control valve, and connect the other system to the pilot of the unload oil passage switching valve. Which are connected to the work unit.

In the present invention, an oil passage is provided in the body of the hydraulic pump, an oil passage is also provided in the body of the opening / closing valve, the bodies are connected to each other, and the respective oil passages are connected.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a description will be given of an embodiment in which the piping structure of the present invention is provided as a hydraulic working machine in an excavating and turning work vehicle (backhoe). FIG. 1 is an overall side view of an excavation and turning work vehicle having a hydraulic circuit according to the present invention, FIG. 2 is a hydraulic circuit diagram of a first embodiment, and FIG. 3 is a hydraulic circuit diagram of a second embodiment.
4 is a hydraulic circuit diagram of the third embodiment, FIG. 5 is a side view showing a hydraulic pump and an opening / closing valve, FIG. 6 is a front view thereof, and FIG. 7 is a conventional hydraulic circuit diagram. As shown in FIG. 1, the excavation revolving work vehicle rotatably supports a revolving frame 8 via a revolving base bearing 7 having an axis in the vertical direction at the upper center of the crawler type traveling device 1. A blade 10 is vertically rotatably disposed at one of the front and rear ends of the traveling device 1. A bonnet 9 that covers the engine and the like is disposed above the revolving frame 8, and a seat 22 is attached above the bonnet 9. In front of the seat 22,
The front column 19 is provided with levers for running operation, turning operation and operation of the working machine 2. A step 20 is arranged between the front column 19 and the hood 9.

A working machine 2 is attached to the front end of the revolving frame 8, and a boom bracket 12 is attached to the working machine 2 so as to be rotatable left and right. It is rotatably supported.
The boom 6 is bent forward in the middle, and is formed in a substantially V shape in a side view. An arm 5 is rotatably supported at the other end of the boom 6, and a bucket 4 as a work attachment is rotatably supported at the tip of the arm 5.

A boom cylinder bracket 25 provided on the front surface of the boom bracket 12 and the boom 6 in the middle thereof.
The boom cylinder 23 is interposed between the arm cylinder bottom bracket 26 and the bucket cylinder bracket 27 provided at the base end of the arm 5, and the arm cylinder 29 is interposed between the boom cylinder 23 and the bucket cylinder bracket 27.
A bucket cylinder 24 is interposed between the bucket cylinder bracket 27 and the stay 11 connected to the bucket 4.

Thus, the boom 6 is rotated by the boom cylinder 23, the arm 5 is rotated by the arm cylinder 29, and the bucket 4 is rotated by the bucket cylinder 24. The boom cylinder 23, the arm cylinder 29, and the bucket cylinder 24 are hydraulic cylinders, and each of the cylinders 23, 29, and 24 is a front column 1.
By operating the operation lever disposed on the switch 9, the switching valve disposed below the switch is switched, and the pressure oil from the hydraulic pump is supplied to perform expansion / contraction drive.

A swing cylinder 17 is disposed on a side portion of the swing frame 8, a base portion of the swing cylinder 17 is pivotally supported by the swing frame, and a tip end of a cylinder rod of the swing cylinder 17 is connected to a boom bracket 12. Cage,
The swing cylinder 17 allows the boom bracket 12 to rotate left and right with respect to the revolving frame 8 and the working machine 2 to rotate left and right.

Further, the revolving frame 8 is moved by an operation of a revolving motor (not shown) provided above the revolving base bearing 7 so that the revolving frame 8 is rotated by 36.
The blade 10 can be turned to the left and right, and the blade 10 is provided at the rear of the earth dumping plate and the track frame 3 of the crawler type traveling device 1.
The blade cylinder 14 is interposed between the upper and lower ends of the blade cylinder 14 so that it can be moved up and down. The swing motor 13 is a hydraulic motor. Further, traveling hydraulic motors are respectively disposed inside the drive sprockets 16 and 16 arranged on one side of the front and rear of the track frame 3 so that the crawler type traveling device 1 can be driven to travel. The hydraulic cylinders and hydraulic motors that serve as these hydraulic actuators can be driven by operating the operation levers and pedals provided on the front column 19 and the step 20.

Next, the hydraulic circuit in the excavating and swinging work vehicle in which the hydraulic cylinders and hydraulic motors that serve as hydraulic actuators are arranged will be described with reference to FIG. First, the output shaft of the engine E housed in the bonnet 9 is driven by the first hydraulic pump 31 and the second hydraulic pump 32, which are hydraulic pressure supply sources, being interlocked and connected in parallel. An unload oil passage switching valve 35 is connected to the two output oil passages 33 and 34 of the first hydraulic pump 31, and the unload oil passage switching valve 35 is connected to center oil passages 36 and 40 and an oil tank. An unloading oil passage 49 communicating therewith is connected, and the center oil passages 36 and 40 are connected to respective control valves so that respective hydraulic actuators can be driven. A relief valve (not shown) for setting the output hydraulic pressure in the first center oil passage 36 on the output side of the output oil passage 33.
Are connected in parallel, and a travel motor direction switching valve 37R for switching the oil supply to the travel hydraulic motor (not shown) on the left and right side (the right side in this embodiment) and the oil supply to the boom cylinder 23 (FIG. 1). Direction switching valve for boom 38
And a bucket direction switching valve 39 for switching the oil supply to the bucket cylinder 24 (FIG. 1) are connected in tandem. The pilot port 38 is provided on the operation portion of the boom direction switching valve 38 and the bucket direction switching valve 39.
a. 38b, 39a, and 39b are formed, and by operating the operation lever 43, the pilot valve described later is switched to switch the control valve, and the hydraulic actuator (boom cylinder 23, bucket cylinder 24) can be operated.

Further, the second center oil passage 40 is connected to the output oil passage 34.
Is connected, and a relief valve (not shown) for setting the output hydraulic pressure is connected in parallel to the second center oil passage 40, and is connected to a traveling hydraulic motor (not shown) on the left and right other sides (left side in this embodiment). Direction switch valve 37L for traveling motor that switches the oil supply of
A swing direction switching valve 41 for switching the oil supply to the swing cylinder 17 (FIG. 1), and the arm cylinder 2
9 (FIG. 1) is a tandem connection of an arm direction switching valve 42 for switching the oil supply. Pilot ports 41a, 41b, 42a, 42b are provided on the operation portions of the swing direction switching valve 41 and the arm direction switching valve 42.
Is formed, and a control valve is switched by switching a pilot valve described later by operating the operation lever 44, and the hydraulic actuator (swing cylinder 17, arm cylinder 29) can be operated. However, in the present embodiment, the switching valves 37R, 38.
Although the number of 39, 37L, 41, and 42 is 6, the number and the number of hydraulic actuators to be operated are not limited, and other switching valves can be added.

The traveling motor direction switching valve 37R and the traveling motor direction switching valve 37L are provided with an operating lever 37a.
By operating 37b, the boom direction switching valve 38,
The bucket directional control valve 39, the swing directional control valve 41, and the arm directional control valve 42 operate by operating the respective operating levers 43 and 44 so that the pressure oil from the first and second hydraulic pumps 31 and 32 is hydraulically actuated. From a neutral position X that does not supply pressure oil to one input / output port of each corresponding hydraulic actuator, or a supply position Z that supplies pressure oil to the other input / output port.
Is switched to. Of these switching valves, for swings, arms, which are switched by the operation levers 43 and 44,
Boom, bucket switching valves 41, 42, 38
-39 is a pilot operated type, and from each pilot valve 56, 57, 58, 59 described later, each pilot port 38a, 38b, 39a, 39b, 41a formed in each switching valve 38, 39, 41, 42.・ 4
When the pilot pressure oil is supplied to the 1b, 42a, and 42b, the neutral position X is switched to the pressure oil supply position Y or Z. Further, the left and right traveling motor direction switching valves 37R and 37L are operation levers 37a which are directly connected to the respective switching valves via linkages or the like.
It is configured as a manual type that switches from the neutral position X to the pressure oil supply position Y or Z based on the operation of 37b.
Incidentally, in the present embodiment, a manual type operation is employed as described above as an operation other than the pilot operation, but the present invention is not limited to this, and the present invention is not limited to the mechanical operation,
The present invention can also be carried out to those in which various operation means such as electric operation are adopted.

Next, the pilot pressure oil supply circuit of the present invention will be described. First, a first embodiment of the pilot pressure oil supply circuit will be described with reference to FIG. A part of the pressure oil supplied from the second hydraulic pump (hydraulic pressure supply source) 32 is used as pilot pressure oil. The pilot pressure oil from the second hydraulic pump 32 is supplied to the open / close valve oil passage 5
It is supplied to the opening / closing valve (safety valve) 50 via 1. The on-off valve 50 is a 4-port 2-position switching valve, and is a switching valve capable of simultaneously switching on / off the oil passages of the two output side systems. The opening / closing valve 50 is provided with an operation lever 50a, and the operation lever 50a can simultaneously switch on / off two oil passages (two output ports). That is, it is possible to switch between a position where the pressure oil can be sent to the secondary side and a position where the pressure oil on the secondary side is drained.

The pump port of the opening / closing valve 50 is connected to the opening / closing valve oil passage 51, the tank port is connected to the oil tank, and the first output port on the secondary side is the pilot valve 56.
The pilot oil passage 53 to 57, 58 and 59 is connected to the second output port, and the oil passage 52 to the pilot operating portion 35a of the unload oil passage switching valve 35 is connected to the second output port. Further, a branch is formed at the other end of the pilot oil passage 53, and one ends of the first pilot oil passage 54 and the second pilot oil passage 55 are connected thereto. The other end of the first pilot oil passage 54 is connected to the pump ports of the boom pilot valve 56 and the bucket pilot valve 57, and the other end of the second pilot oil passage 55 is connected to the swing pilot valve 58 and the arm. It is connected to the pump port of the pilot valve 59 so that the pressure oil from the second hydraulic pump 32 can be supplied to each pilot valve 56, 57, 58, 59.

The boom, bucket, swing, and arm pilot valves 56, 57, 58.5
From 9, the pilot pressure oil is used for the boom, bucket, swing, arm direction switching valves 38, 39 ,.
41 and 42 of the pilot operating parts 38a and 38b, respectively
-Supplied to 39a, 39b, 41a, 41b, 42a, 42b. Therefore, when the operation lever 50a is turned off, the first output port and the second output port are closed,
The pressure oil from the pump port flows to the tank port, that is, the oil tank, and the pressure oil is not fed to the pilot valves 56, 57, 58, 59 for the boom, bucket, swing, and arm, and the operation lever 43. Even if 44 is operated, the control valve cannot be switched and the hydraulic actuator will not operate. Further, since the pressure oil is not sent to the pilot operation portion 35a of the unload oil passage switching valve 35, the pressure oil from the output oil passages 33 and 34 does not flow to the center oil passages 36 and 40 and the unload oil passage 49. It flows to the tank and is not sent to the hydraulic actuator. Therefore, even if the operation levers 37a and 37b are operated, the vehicle does not travel. When the operation lever 50a is turned on,
The first output port and the second output port are opened, pressure oil is supplied to the pilot oil passage 53 and the oil passage 52 to the unload oil passage switching valve 35, the control valve can be switched, and the hydraulic actuator can also be driven. Of.

In this way, by supplying the pilot pressure oil from the second hydraulic pump 32 to the opening / closing valve 50 capable of simultaneously switching on / off the oil passages of the two systems, the opening / closing valve 50 is supplied to the pilot valve. Pilot oilway 5
3 and the oil passage 52 to the pilot operation portion 35a of the unload oil passage switching valve 35 can be individually connected, and branching can be reduced. Therefore, the number of pipes can be reduced, productivity can be improved, and cost can be reduced.

Next, a second embodiment of the pilot pressure oil supply circuit will be described with reference to FIG. A part of the pressure oil supplied from the second hydraulic pump 32 is used as pilot pressure oil. Pilot pressure oil from the second hydraulic pump 32 is supplied to the opening / closing valve 60 via the opening / closing valve oil passage 61. The on-off valve 60 is composed of a 5-port 2-position switching valve, and the operating lever 60a simultaneously turns on the three oil passages (three output ports) on the output side.
It is an on-off valve that can be switched off. In this embodiment, the three oil passages on the output side are open / close valves that can be switched on and off at the same time. However, the present invention is not limited to this, and three or more oil passages on the output side (secondary side) can be used. It is also possible to use an opening / closing valve capable of simultaneously switching on / off the valve provided in).

A pump port of the opening / closing valve 60 is connected to an opening / closing valve oil passage 61, a tank port is connected to an oil tank, a first pilot oil passage 63 is provided at a first output port, and a second pilot port is provided at a second output port. The pilot oil passage 64 is connected to the third output port, and the oil passage 62 to the pilot operating portion 35a of the unload oil passage switching valve 35 is connected. When the operation lever 60a is turned off, the first output port, the second output port, and the third output port are closed, the pressure oil from the first port flows to the tank port, that is, the oil tank, and the control valve cannot be switched. In addition, the hydraulic actuator cannot be driven. When the operation lever 60a is turned on, the first output port, the second output port, and the third output port are opened, and the first and second pilot oil passages 63.6 are opened.
4 and the oil passage 35b to the unload oil passage switching valve 35
The pressure oil is supplied to the control valve, the control valve can be switched, and the hydraulic actuator can be driven. The first pilot oil passage 63 is connected to a boom pilot valve 56 and a bucket pilot valve 57, and the other end of the second pilot oil passage 64 has a swing pilot valve 58.
And the pilot valve 59 for the arm to connect the pressure oil from the second hydraulic pump 32 to each pilot valve 56.
It is configured to supply to 57, 58 and 59. And
Similar to the first embodiment, the pilot pressure oil is used for the boom,
Pilot valve 5 for bucket, swing, arm
From 6/57/58/59, the pilot operation parts 38a / 3 for the boom, bucket, swing, arm
8b ・ 39a ・ 39b ・ 41a ・ 41b ・ 42a ・ 42
b can be supplied.

As described above, the pilot pressure oil from the second hydraulic pump 32 is supplied to the opening / closing valve 60 capable of simultaneously switching on / off the oil passages of at least three systems, and the opening / closing valve 60 is connected to the pilot valve 56.・ 57 ・ 58.5
9, first and second pilot oil passages 63 and 64, and a pilot operation portion 35a of the unload oil passage switching valve 35
The oil passages 62 to can be individually connected to further reduce branching. Therefore, the number of pipes can be further reduced, the production is improved, and the cost reduction effect is improved.

Next, a third embodiment of the pilot pressure oil supply circuit will be described with reference to FIGS. The pilot pressure oil supply circuit is substantially the same as that of the second embodiment, and includes a pump body 70 and an opening / closing valve 60 body 60b.
It is an object of the present invention to simplify the piping structure by integrally connecting the above with the piping forming the opening / closing valve oil passage 61. That is, as shown in FIGS. 5 and 6, the valve body 60b of the opening / closing valve 60 is connected and fixed to the pump body 70 that houses the first hydraulic pump 31 and the second hydraulic pump 32. The body 70 is provided with a discharge oil passage 70a communicating with the discharge portion of the second hydraulic pump 32, and the body 60b of the opening / closing valve 60 is provided with an oil passage 60c communicating with the discharge oil passage 70a. ing. Therefore, the pressure oil from the second hydraulic pump 32 passes through the oil passage 70 a of the second hydraulic pump 32 and opens / closes the valve 60 and the oil passage 60.
is supplied to c. The first hydraulic pump 31 is composed of a variable hydraulic pump, and the discharge oil amount can be changed by the operation unit 74. A spool 60d is slidably disposed inside the opening / closing valve 60, and one end of the spool 60d protrudes from the body 60b and is connected to an operating lever 60a via a link mechanism or the like, so that the operating lever 60d.
The opening / closing valve 60 is switched on / off by the sliding operation by the rotation of a, and when it is on, as in the second embodiment,
The pressure oil from the oil passage 60c is supplied to the first and second pilot oil passages 63 and 64 and the oil passage 62 to the unload oil passage switching valve 35. As shown in FIG. 4, the on-off valve 6
0 structure and pilot valves 56, 57, 58.5
The oil passages 63 and 64 to 9 have the same structure as in the second embodiment, and pilot pressure oil is used for the boom, bucket, swing, arm pilot valves as in the first embodiment. From 56.57.58.59, for the boom,
Pilot port 3 for bucket, swing, arm
8a, 38b, 39a, 39b, 41a, 41b, 42
It is supplied to a 42b.

With the above structure, the second hydraulic pump 32
Since the bodies 70 and 60b of the opening / closing valve 60 are connected to each other, and the oil passages 70a and 60c are provided in the bodies 70 and 60b, and the oil passages are connected to each other, the space between the second hydraulic pump 32 and the opening / closing valve 60 is It is possible to reduce the number of pipes provided in the opening / closing valve oil passage 61 (second embodiment). Therefore,
Conventionally, as shown in FIG. 7, from the discharge part of the hydraulic pump 101 to 102.104.105.106.107.108.
However, in the first embodiment, as shown in FIG. 2, the number of branch pipes can be reduced by one, and at least 5 pipes of 51, 52, 53, 54, and 55 are required. It becomes possible to communicate by piping, and in the second embodiment, as shown in FIG. 3, the number of branch pipes is reduced by two as compared with the conventional one, and communication is achieved by four pipings 61, 62, 63 and 64. be able to. Furthermore, in the third embodiment, as shown in FIG. 4, the piping of 61 can be eliminated, the three piping can communicate with each other, the number of piping can be reduced, and the bodies can be connected to each other by bolts or the like. Since it is fixed, it becomes compact and production is improved, and the cost reduction effect is improved.

[0026]

Since the present invention is constructed as described above,
The following effects are achieved.

That is, as described in claim 1, the hydraulic pressure supply control of the plurality of hydraulic actuators is configured to be performed by each corresponding control valve, and the switching operation of each control valve is controlled by the pilot operation means and the manual operation means. In a working machine in which both operating means such as electric operating means and the like are used, an unloading oil passage leading to an oil tank, an oil passage supplying the control valve of each hydraulic actuator, and a hydraulic pressure supply. In addition to providing an unloading oil passage switching valve with the power source, an opening / closing valve for simultaneously switching on or off the output ports of two systems is provided in the discharge oil passage of the hydraulic pump, and the output of one system is output. Connect the port to the valve that switches the supply of pilot pressure oil to the control valve,
Since the other system is connected to the pilot operation part of the unload oil passage switching valve, the number of pipes can be reduced, the number of branch pipes can be reduced, the number of assembling steps can be reduced, and the productivity can be improved. The cost can be reduced.

According to a second aspect of the present invention, the hydraulic pressure supply control of the plurality of hydraulic actuators is performed by each corresponding control valve, and the switching operation of each control valve is performed by a plurality of pilot operating means and a manual operating means. In a working machine in which an operating means such as an electric operating means is used, an unloading oil passage leading to an oil tank, an oil passage supplying the control valve of each hydraulic actuator, and a hydraulic pressure supply source. In addition to providing an unload oil passage switching valve between and, an opening / closing valve for switching on or off at least three output ports of the hydraulic pump at the same time is provided in the discharge oil passage of the hydraulic pump, and at least two system output valves are provided. Connect the output port to the valve that switches the supply of pilot pressure oil to the control valve, and connect the other system to the pilot of the unload oil passage switching valve. Having connected to the work unit, further reduces piping number, the number of the branch pipe can also be reduced, assembling steps also can be reduced, productivity improvement, the cost reduction effect is enhanced.

Since the oil passage is provided in the body of the hydraulic pump, the oil passage is also provided in the body of the opening / closing valve, the bodies are connected to each other, and the respective oil passages are connected to each other, the number of pipes is increased. Can be further reduced, space can be saved, the number of assembling steps can be reduced, the assembling accuracy can be improved, and the productivity can be improved.
The cost reduction effect increases.

[Brief description of drawings]

FIG. 1 is an overall side view of an excavation and swing work vehicle having a hydraulic circuit according to the present invention.

FIG. 2 is a hydraulic circuit diagram of the first embodiment.

FIG. 3 is a hydraulic circuit diagram of a second embodiment.

FIG. 4 is a hydraulic circuit diagram of a third embodiment.

FIG. 5 is a side view showing a hydraulic pump and an opening / closing valve.

FIG. 6 is a front view of the same.

FIG. 7 is a conventional hydraulic circuit diagram.

[Explanation of symbols]

1 crawler type traveling vehicle 31 First hydraulic pump 32 Second hydraulic pump 35 Unload oil passage switching valve 37 Directional switching valve for traveling motor 38 Directional valve for boom 39 Bucket Directional Valve 41 Directional switching valve for swing 42 Directional switching valve for arm 50 open / close valve 51 Open / close valve oil passage 53 Pilot oil passage 60 open / close valve 63 First pilot oil passage 64 Second pilot oil passage

Front page continued (51) Int.Cl. ⁷ Identification code FI theme code (reference) // E02F 9/24 F15B 11/00 HF term (reference) 2D003 AA01 BA07 CA03 DA03 EA04 2D015 GA02 GB02 3H045 AA16 AA24 AA32 BA00 DA15 DA31 EA04 3H089 AA05 AA60 BB27 CC11 DA03 DA08 DB07 EE22 GG02 JJ01

Claims (3)

[Claims] 1. The hydraulic supply control of a plurality of hydraulic actuators is configured to be performed by each corresponding control valve, and the switching operation of each control valve is performed by other than pilot operating means, manual operating means, electrical operating means, or the like. In the working machine in which both the operating means and the operating means are used, the unloading oil passage leading to the oil tank, the oil passage supplying the control valve of each hydraulic actuator, and the hydraulic supply source are unloaded. In addition to providing an oil passage switching valve, an opening / closing valve for simultaneously switching on / off two output ports of the hydraulic pump is provided in the discharge oil passage of the hydraulic pump, and the output port of one system is connected to the control valve. Oil for a working machine, characterized in that it is connected to a valve for switching the supply of pilot pressure oil, and the other system is connected to the pilot operation part of the unload oil passage switching valve. Pressure circuit. 2. The hydraulic supply control of a plurality of hydraulic actuators is configured to be performed by each corresponding control valve, and the switching operation of each control valve is performed by a plurality of pilot operating means and manual operating means or electrical operating means, etc. In a work machine in which the operation means with other operation means of is used,
An unloading oil passage leading to an oil tank, an oil passage supplying the control valve of each hydraulic actuator, and an unloading oil passage switching valve provided between the oil pressure supply source and the discharge oil passage of the hydraulic pump. An on-off valve for switching on or off at least three output ports at the same time,
Work characterized in that at least two output ports of the system are connected to a valve for switching the supply of pilot pressure oil to the control valve, and the other system is connected to the pilot operation part of the unload oil passage switching valve. The hydraulic circuit of the machine. 3. An oil passage is provided in a body of the hydraulic pump, an oil passage is also provided in a body of the opening / closing valve, the bodies are coupled to each other, and the respective oil passages are connected to each other. The hydraulic circuit of the working machine according to claim 2.