JP2000120616A - Hydraulic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit that can supply operating fluid to a pilot port of a directional switching valve while a controller does not provide a command signal. SOLUTION: A selection switching valve 74 is provided between individual remote control valves 59, 79, 89 and pilot ports 55a, 75a, 85a of direction switching valves 55, 75, 85 composing hydraulic circuits to be switchable in a lamp to a state where the remote control valves 59, 79, 98 are connected to the pilot ports 55a, 75a, 85a through electromagnetic valves 62, 82, 92, or to a state where the remote control valves 59, 79, 89 are connected to the pilot ports 55a, 75a, 85a without the electromagnetic valves 62, 82, 92. Operating the selection switching valve 74 directly provides the fluid pressure of the operating fluid from the remote control valves 59, 79, 89 to the pilot ports 55a, 75a, 85a of the direction switching valves 55, 75, 85.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit.

[0002]

2. Description of the Related Art In recent years, construction machines equipped with offset attachments have been used in order to efficiently perform gutter excavation work.

The structure of an example of an offset attachment will be described below with reference to FIGS. 3 and 4.

The offset type attachment includes a main boom 1, a boom raising / lowering cylinder 5, an intermediate boom 11, a tip boom 16, a link bar 13, an offset cylinder 22, an arm 29, an arm rotating cylinder 31, a bucket 37, and a bucket. A rotation cylinder 40 is provided.

[0005] The base end of the main boom 1 is pivotally attached to a rear upper portion of a bracket 3 provided on the revolving unit 2 of the construction machine main body by a pin 4 extending substantially horizontally in the width direction of the revolving unit 2.

[0006] The cylinder body 6 of the boom hoisting cylinder 5
The base end of the main boom 1 is pivotally attached to the front lower portion of the bracket 3 by a pin 7 parallel to the pin 4. The tip of the piston rod 8 of the boom hoisting cylinder 5 is the tip of the main boom 1. Is pivotally connected to a bracket 9 provided at the same position by a pin 10 parallel to the pin 4.

The base end of the intermediate boom 11 is pivotally connected to the front end of the main boom 1 by a pin 12 extending in a direction perpendicular to the pin 4.

[0008] The tip boom 16 is provided with the intermediate boom 11 described above.
Is pivotally connected to a tip of the pin by a pin 17 parallel to the pin 12.

The distal boom 16 is located above the intermediate boom 11 from the intermediate portion between the proximal end and the distal end of the distal boom 16 toward the proximal end of the intermediate boom 11 when viewed from the side. The cylinder support 18 is provided so as to extend.

The link bar 13 is arranged on the left side of the intermediate boom 11 and substantially parallel to the intermediate boom 11.

The base end of the link bar 13 is attached to a bracket 14 provided on the left end of the main boom 1 by a pin 1.
2 and a distal end of the link bar 13 is pivotally attached to a bracket 19 provided on the left side of the tip boom 16 by a pin 20 parallel to the pin 12. A parallelogram link 21 is formed by the intermediate boom 11 and the link bar 13 and the like.

The offset cylinder 22 is disposed on the right side of the intermediate boom 11.

The base end of the cylinder body 23 of the offset cylinder 22 is pivotally mounted on a bracket 24 provided on the right end of the main boom 1 by a pin 25 parallel to the pin 12. A distal end of the piston rod 26 is attached to a bracket 27 provided on the right side of the distal end of the intermediate boom 11 by a pin 28 parallel to the pin 25.
Is pivoted by

The proximal end of the arm 29 is pivotally connected to the distal end of the distal boom 16 by a pin 30 parallel to the pin 4.

The base end of the cylinder body 32 of the arm rotation cylinder 31 is connected to the cylinder support portion 18 of the distal end boom 16.
A pin 33 parallel to the pin 4 is pivotally connected to the arm 29. The distal end of the piston rod 34 of the arm rotation cylinder 31 is connected to a bracket 35 provided at the base end of the arm 29.
Are pivotally connected by a pin 36 parallel to the pin 4.

A bracket 38 is provided on the back of the bucket 37, and the bracket 38
9 is pivotally connected to a tip of the pin 9 by a pin 39 parallel to the pin 4.

The base end of the cylinder body 41 of the bucket rotating cylinder 40 is pivotally connected to a bracket 42 provided at the base end of the arm 29 by a pin 43 parallel to the pin 4.

At the tip of the piston rod 44 of the bucket rotating cylinder 40, one end of each of a bucket link 45 and an arm link 46 is connected to a pin 4 parallel to the pin 4.
7, the other end of the bucket link 45 is pivotally connected to the bracket 38 on the back of the bucket 37 by a pin 48 parallel to the pin 4, and the other end of the arm link 46 is The arm 29 is pivotally mounted near a tip of the arm 29 by a pin 49 parallel to the pin 4.

In the offset type attachment shown in FIGS. 3 and 4, when a working hydraulic pressure is applied to a boom raising / lowering cylinder 5 from a main hydraulic pump (not shown) provided on a revolving unit 2 of a construction machine body, a piston is provided. As the rod 8 advances or retreats, the main boom 1 moves up and down around the pin 4.

When operating hydraulic pressure is applied to the offset cylinder 22 from the main hydraulic pump, the intermediate boom 11 swings right and left about the pin 12 as the piston rod 26 advances or retreats.

At this time, since the distal end boom 16 is connected to the main boom 1 via the parallelogram link 21 formed by the intermediate boom 11 and the link bar 13, etc.
Even if the intermediate boom 11 swings with respect to the main boom 1, the angle of the tip boom 16 with respect to the main boom 1 as viewed from above does not change.

On the other hand, when operating hydraulic pressure is applied to the arm rotation cylinder 31 from the main hydraulic pump, the arm 29 rotates about the pin 30 as the piston rod 34 advances or retreats.

Further, when an operating oil pressure is applied to the bucket rotating cylinder 40 from the main hydraulic pump, the bucket 37 rotates about the pin 39.

In the offset type attachment as described above, the main boom 1, the intermediate boom 11, and the tip boom are operated by operating the boom raising / lowering cylinder 5, the offset cylinder 22, the arm rotating cylinder 31, and the bucket rotating cylinder 40. 16, arm 29, bucket 3
When each member such as 7 is positioned inside the turning radius of the turning body 2, the gutter excavation work can be efficiently performed even in a narrow place.

In recent years, utilizing the characteristics of an offset type attachment, the offset type attachment is applied to a construction machine (ultra small turning machine) having a very small turning radius to perform excavation work on a narrow road or the like. Has been done.

In general, a micro turning machine is not provided with a closed cab surrounding a driver's seat like a large construction machine, and only an open cab (canopy) is a means for protecting a driver in many cases. , Main boom 1 for revolving superstructure 2
The swing angle of the intermediate boom 11 with respect to the main boom 1, the pivot angle of the arm 29 with respect to the tip boom 16,
Depending on the condition of the rotation angle of the bucket 37 with respect to the arm 29, the excavation claw of the bucket 37 may interfere with the cab or enter the inside of the cab.

Therefore, for the purpose of protecting the driver, the hydraulic circuit for driving the offset type attachment is provided with an interference preventing function for preventing each member constituting the offset type attachment such as the bucket 37 from interfering with the cab. There are things that let me

An outline of an example of a hydraulic circuit of an offset type attachment having a function of preventing interference with a cab will be described below with reference to FIG.

The hydraulic circuit includes position detection sensors 67, 68 such as a main pump 50, a pilot pump 51, a boom-up / down directional control valve 55, a boom-up / down remote control valve 59, a boom-up / down restriction electromagnetic valve 62, a potentiometer, and the like. 6
9, 70, a data storage unit 71, and a controller 72.

An oil suction port of the main pump 50 and the pilot pump 51 has a hydraulic oil suction pipe 5 communicating with an oil tank 52.
3, 54 are connected.

The boom raising / lowering direction switching valve 55 is a three-position switching valve of a pilot pressure switching type, and its pump port is connected to a hydraulic oil supply pipe 56 communicating with the oil discharge port of the main pump 50. A hydraulic oil return pipe 57 communicating with the oil tank 52 is connected to the port.

The hydraulic oil supply pipe 56 is provided with a relief valve (not shown) for returning hydraulic oil to the oil tank 52 in accordance with the internal pressure of the pipe.

Further, both switching ports of the boom raising / lowering directional switching valve 55 are connected to both fluid chambers of the boom raising / lowering cylinder 5 via conduits 58a and 58b, respectively.

The spool of the boom hoisting direction switching valve 55 is normally set at a neutral position where the pump port is blocked by an elastic body such as a spring, and fluid pressure is applied to one of the pilot ports 55a and 55b. When given, the spool moves to a communication position that allows the pump port to communicate with one of the switching ports.

The boom raising / lowering remote control valve 59 is a manual switching type two-way pilot pressure switching valve, and its pump port is connected to a pilot line 60 communicating with the oil discharge port of the pilot pump 51. The port is connected to a pilot conduit 61 communicating with the oil tank 52.

The boom raising / lowering remote control valve 59 is configured such that the pump port and the tank port are selectively connected to one of the two switching ports in accordance with the tilt direction of the operation lever 59a. .

The pilot line 60 is provided with a relief valve (not shown) capable of returning hydraulic oil to the oil tank 52 in accordance with the pipe internal pressure.

The boom rising control solenoid valve 62 is a two-position proportional pressure reducing valve of an electromagnetic switching type, and has two primary ports and one secondary port.

When the solenoid 62a is not excited, the spool of the boom standing-up regulating solenoid valve 62 has one primary port blocked by an elastic body such as a spring and the other primary port connected to the secondary port. When the exciting current is applied to the solenoid 62a, the spool moves in proportion to the current value, and the hydraulic oil flowing from one primary port to the secondary port is set. Increase pressure value.

A pilot line 63 communicating with one of the switching ports of the remote control valve 59 for raising and lowering the boom is connected to one primary side port of the solenoid valve 62 for restricting the boom rising, and the other primary side. A hydraulic oil return pipe 64 communicating with the oil tank 52 is connected to the port.

Further, to one pilot port 55a of the above-described direction switching valve 55 for boom raising / lowering, a secondary port of a solenoid valve 62 for boom standing-up restriction is connected via a pilot line 65. Boom hoisting direction switching valve 55
The other switching port of the remote control valve 59 for raising and lowering the boom is connected to the other pilot port 55b via a pilot line 66.

The position detection sensor 67 indicates the elevation angle of the main boom 1 with respect to the revolving unit 2, the position detection sensor 68 indicates the swing angle of the intermediate boom 11 with respect to the main boom 1, and the position detection sensor 69 indicates the angle with respect to the tip boom 16. The position detection sensor 70 is configured to detect the rotation angle of the arm 29 and the rotation angle of the bucket 37 with respect to the arm 29 (the main boom 1, the intermediate boom 11, the tip boom 16, the arm 29, and 3 and 4 for the bucket 37).

The data storage 71 stores data relating to the interference between the members constituting the offset type attachment and the cab of the construction machine (the undulation angle of the main boom 1 with respect to the revolving unit 2 and the swing of the intermediate boom 11 with respect to the main boom 1). angle,
The rotation angle of the arm 29 with respect to the tip boom 16 and the rotation angle of the bucket 37 with respect to the arm 29 are stored as data signals 71s.

The controller 72 includes the position detection sensors 67 to 7
0 based on the position detection signals 67 s to 70 s output from 0 and the data signal 71 s stored in the data storage 71,
A command signal 62s is output to 2a, and an alarm signal 73s is output to the alarm 73.

The controller 72 includes position detection sensors 67 to
70 is damaged or the position detection sensors 67 to 7
When the cable connecting the controller 72 and the controller 72 is disconnected and the position detection signals 67 s to 70 s are not input to the controller 72, or when the controller 72 itself breaks down, the electromagnetic valve 62 for restricting the boom standing up is used. The output of the command signal 62s to the solenoid 62a is stopped.

In the hydraulic circuit shown in FIG. 2, when the construction machine is running, each of the position detection sensors 67 to 70
Output position detection signals 67 s to 70 s to the controller 72. The controller 72 generates an offset type attachment from the position detection signals 67 s to 70 s and the data signal 71 s stored in the data storage 71. Main boom 1, middle boom 11, tip boom 1 to constitute
6. The positional relationship between the members such as the arm 29 and the bucket 37 and the cab of the construction machine is required.

At this time, the main boom 1, the intermediate boom 11, and the tip boom 1 constituting the offset type attachment
6. If these members do not interfere with the cab of the construction machine even when the arm 29, the bucket 37 and the like are displaced to some extent, the controller 72 controls the boom erecting solenoid valve 62 from the controller 72. A command signal 62 s having a large current value is output to the solenoid 62 a so that the spool of the boom standing-up regulating solenoid valve 62 has a maximum pressure value of the hydraulic oil flowing from one primary port to the secondary port. Moving.

In such a state, the operation lever 59
is tilted to make the pump port of the boom-relief remote control valve 59 communicate with one of the switching ports, the hydraulic pressure of the hydraulic oil discharged from the pilot pump 51 changes the pilot line 60, the boom-relief remote operation. A valve 59, a pilot line 63, a boom standing-up restricting solenoid valve 62, and a pilot line 65 are provided to a pilot port 55 a of a boom hoisting direction switching valve 55.

As a result, the pipe line 5 is connected to the pump port of the boom hoisting direction switching valve 55 and the boom hoisting cylinder 5.
Hydraulic oil discharged from the main pump 50 passes through a hydraulic oil supply pipe 56, a boom hoisting direction switching valve 55, and a pipe line 58a to the boom hoisting cylinder 5. By supplying the fluid to the head-side fluid chamber and increasing the protrusion amount of the piston rod 8 (see FIG. 3),
The undulation angle of the main boom 1 increases.

When the main boom 1, the intermediate boom 11, the tip boom 16, the arm 29, and the bucket 37 are displaced to a certain position and the elevation angle of the main boom 1 is further increased, the bucket 37 approaches the state of interfering with the cab. From the controller 72 to the solenoid 6 of the boom rise control solenoid valve 62.
The current value of the command signal 62s output to 2a decreases.

Accordingly, the pressure value of the hydraulic oil flowing from one primary port to the secondary port of one of the boom rising control solenoid valves 62 decreases, and the main pump 50 moves to the head side fluid chamber of the boom raising / lowering cylinder 5. The flow rate of the supplied working oil decreases, and the displacement speed of the main boom 1 decreases.

At this time, an alarm signal 73s is sent from the controller 72.
Is output to the alarm 73, and when the alarm 73 is operated, the driver is notified of the approach of the bucket 37 to the cab.

Further, when the bucket 37 is located near the cab, the controller 72 does not output the command signal 62s to the solenoid 62a of the electromagnetic valve 62 for restricting the boom rising, and the spool of the solenoid valve 62 for restricting the boom rising is moved by the spring. One primary side port is blocked by an elastic body such as the above, and the secondary side port is positioned so as to communicate with the other primary side port. It is no longer provided to the pilot port 55a of the undulating direction switching valve 55.

As a result, the spool of the boom raising / lowering direction switching valve 55 is set to the neutral position, and the operating oil discharged from the main pump 50 is not supplied to the head side fluid chamber of the boom raising / lowering cylinder 5 and the main boom 1 The displacement stops, and the interference between the components of the offset attachment and the cab is suppressed.

In the hydraulic circuit of the offset type attachment having the function of preventing interference with the cab, the pulling operation component of the hydraulic circuit of the arm rotating cylinder 31 (see FIG. 3) for performing the pulling operation of the arm 29, The push operation component of the hydraulic circuit of the offset cylinder 22 (see FIG. 4) for performing the leftward movement of the tip boom 16 is also configured substantially in the same manner as that shown in FIG.

[0056]

However, in the hydraulic circuit of the offset type attachment having the function of preventing interference with the cab shown in FIG. 2, the position detection sensors 67 to 70 are provided.
When the command signal 62s is no longer output from the controller 72 to the solenoid 62a of the boom rising control solenoid valve 62 due to damage to the boom, the hydraulic pressure of the hydraulic oil is applied to the pilot port 55a of the boom raising / lowering direction switching valve 55. Cannot be given.

For this reason, the main boom 1, the intermediate boom 11, and the tip boom 1 constituting the offset type attachment are provided.
6, the construction machine could not be quickly moved from the work site to another place by displacing the arm 29 and the bucket 37.

The present invention has been made in view of the above circumstances, and has a hydraulic pressure provided with an electromagnetic valve controlled between a pilot port of a direction switching valve and a remote control valve in accordance with a command signal from a controller. It is an object of the present invention to provide a circuit in which a working fluid can be supplied to a pilot port of a directional control valve even when a command signal is not output from a controller.

[0059]

In order to achieve the above object, according to the first aspect of the present invention, each directional control valve for switching the direction of the working fluid supplied from the main pump to the actuator is provided for each direction switching valve. A remote control valve capable of supplying a working fluid discharged from a pilot pump to a pilot port of the switching valve; and a remote control valve provided between the remote control valve and at least one pilot port of the directional switching valve, and an output from the controller. In the hydraulic circuit having a solenoid valve controlled by a command signal, the remote control valve is connected to the pilot port via the solenoid valve between the remote control valve and at least one pilot port of the direction switching valve. A selection switching valve that can be switched collectively to a connected state or a state where the remote control valve is connected to the pilot port without passing through the solenoid valve Only to have.

According to the second aspect of the present invention, in addition to the configuration of the hydraulic circuit of the first aspect, the flow of the working fluid from one pilot port of the directional control valve to the remote control valve is permitted. The obtained check valve is provided in a predetermined solenoid valve.

In any one of the hydraulic circuits according to the first and second aspects of the present invention, when the command signal is no longer output from the controller, the selection switching valve is operated to control each direction switching valve. And a remote control valve is connected to the pilot port of the directional control valve by the collective switching, and the fluid pressure of the working fluid is directly applied from the remote control valve to the pilot port of the direction switching valve.

In the hydraulic circuit according to the second aspect of the present invention, the flow of the working fluid from one pilot port of the directional control valve connected to the solenoid valve to the remote control valve is controlled by the check valve. Before the selection switching valve is operated, the actuator is returned to one direction.

[0063]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of a hydraulic circuit according to the present invention. In the drawing, portions denoted by the same reference numerals as those in FIGS. 2 to 4 represent the same components.

This hydraulic circuit includes a main pump 50, a pilot pump 51, a boom-up / down directional control valve 55, a boom-up / down remote control valve 59, an arm rotation directional control valve 75, an arm rotation remote control valve 79, and an offset Direction switching valve 8
5, remote control valve 89 for offset, solenoid valve 62 for boom standing up regulation, solenoid valve 82 for arm pulling regulation, solenoid valve 92 for offset leftward swing regulation, selection switching valve 74, position detection sensors 67, 68, 69, 70, A data storage 71 and a controller 72 are provided.

The boom raising / lowering direction switching valve 55 is a three-position direction switching valve of a pilot pressure switching type, and a pump port thereof is connected to a working oil supply pipe 56 communicating with an oil discharge port of the main pump 50. The oil tank 52 is connected to the tank port.
Is connected to a hydraulic oil return pipe 57 which communicates with the hydraulic fluid.

The two switching ports of the boom hoisting direction switching valve 55 are connected to both fluid chambers of the boom hoisting cylinder 5 via pipes 58a and 58b.

The remote control valve 59 for raising and lowering the boom is a two-way pilot pressure switching valve of a manual switching system, and a pump port thereof is connected to a pilot line 60 communicating with an oil discharge port of a pilot pump 51. The port is connected to a pilot conduit 61 communicating with the oil tank 52.

The boom raising / lowering remote control valve 59 is configured such that the pump port and the tank port are selectively connected to one of the two switching ports in accordance with the tilting direction of the operation lever 59a. .

The directional switching valve 75 for arm rotation has a pilot pressure switching system equivalent to the directional switching valve 55 for boom raising and lowering.
The pump port is connected to a hydraulic oil supply pipe 76 communicating with the oil discharge port of the main pump 50, and the tank port is connected to a hydraulic oil return pipe 77 communicating with the oil tank 52. Have been.

The two switching ports of the arm rotation direction switching valve 75 are connected to both fluid chambers of the arm rotation cylinder 31 via conduits 78a and 78b, respectively.

The arm-rotating remote control valve 79 is a two-way pilot pressure switching valve of a manual switching type, and its pump port is connected to the pilot line 60 communicating with the oil discharge port of the pilot pump 51. The port is connected to a pilot conduit 61 communicating with the oil tank 52.

The arm-rotating remote control valve 79 is configured such that the pump port and the tank port are selectively connected to one of the two switching ports in accordance with the tilt direction of the operating lever 79a. .

The offset directional switching valve 85 is a pilot pressure switching system equivalent to the boom raising / lowering directional switching valve 55.
The pump port is connected to a hydraulic oil supply pipe 86 communicating with the oil discharge port of the main pump 50, and the tank port is connected to a hydraulic oil return pipe 87 communicating with the oil tank 52. Have been.

The two switching ports of the offset direction switching valve 85 are connected to the two fluid chambers of the offset cylinder 22 via pipes 88a and 88b, respectively.

The remote control valve 89 for offset is a two-way pilot pressure switching valve of a manual switching type. The pilot port 60 is connected to the pump port, and the pilot line 60 is connected to the tank port. 61 are connected.

The offset remote control valve 89 is configured such that the pump port and the tank port selectively communicate with one of the two switching ports in accordance with the tilt direction of the operation lever 89a.

The arm pulling control solenoid valve 82 is a two-position proportional pressure reducing valve of an electromagnetic switching type equivalent to the boom standing up control solenoid valve 62, and an offset left swing restriction solenoid valve 92.
Is an electromagnetic switching type two-position switching valve.

One of the primary ports of the boom rise control solenoid valve 62, the arm pulling control solenoid valve 82, and the offset leftward swing control solenoid valve 92 is connected to a boom up / down remote control valve 59 and an arm rotation remote control valve. 79, is connected to pilot pipelines 63, 83, 93 communicating with one switching port of the remote control valve 89 for offset, and the other primary port is connected to a hydraulic oil return pipe 64 communicating with the oil tank 52. ing.

The selection switching valve 74 is a three-circuit manual switching system.
This is a position switching valve, and has two primary ports and one secondary port for each circuit.

The selection switching valve 74 includes an operation lever 74a
Is configured such that the secondary port of each circuit selectively communicates with only one of the two primary ports in accordance with the tilt direction of.

To one primary port of each circuit of the selection switching valve 74, pilot lines 100, 80, 90 communicating with the secondary ports of the regulating solenoid valves 62, 82, 92 are connected. A pilot line 1 communicating with the pilot lines 63, 83 and 93 is connected to the other primary port of the circuit.
01, 81 and 91 are connected.

Further, one of the pilot ports 55a, 75a, 75a, 75a,
85a is connected to the secondary port of the selection switching valve 74 via pilot lines 102, 112, 122, and to the other pilot ports 55b, 75b, 85b of the directional switching valves 55, 75, 85. Is connected to the other switching port of the remote control valve 59 for boom raising / lowering, the remote control valve 79 for rotating the arm, and the remote control valve 89 for offset via the pilot lines 103, 113, 123.

The controller 72 includes the position detection sensors 67 to 7
On the basis of the position detection signals 67 s to 70 s output from 0 and the data signal 71 s stored in the data storage 71, the boom rising restriction electromagnetic valve 62, the arm pulling restriction electromagnetic valve 82, the offset leftward restriction electromagnetic Command signals 62s, 8 to solenoids 62a, 82a, 92a of valve 92
2s, 92s, and an alarm signal 73s to the alarm 73.

The controller 72 includes the position detection sensors 67 to
70 is damaged or the position detection sensors 67 to 7
When the cable connecting the 0 to the controller 72 is disconnected and the position detection signals 67 s to 70 s are not input to the controller 72, or when the controller 72 itself breaks down, each of the regulating solenoid valves 62, 82, 92 solenoids 62a, 82a,
The output of the command signals 62s, 82s, and 92s to 92a is stopped.

Further, the solenoid valve 62 for restricting the boom rising and the solenoid valve 82 for restricting the pulling of the arm are connected from the secondary port to one primary port (one of the switching ports of the remote control valves 59 and 79). Check valve 1 capable of permitting hydraulic oil to flow
04 and 84 are provided.

The operation of the hydraulic circuit shown in FIG. 1 will be described below.

The position detection sensors 67 to 70 are not damaged, and the controller 72 issues a command signal 6 to the solenoids 62a, 82a, 92a of the regulating solenoid valves 62, 82, 92.
When 2s, 82s, and 92s are output normally, the spool of the selection switching valve 74 is set so that one primary port in each circuit communicates with the secondary port.

At this time, in the controller 72, a position detection signal 67 output from each of the position detection sensors 67 to 70 is output.
The main boom 1, the intermediate boom 11, and the tip boom 1, which form an offset attachment, based on s to 70 s and the data signal 71 s stored in the data storage 71
6, the positional relationship between the members such as the arm 29 and the bucket 37 and the cab of the construction machine is required (for the main boom 1, the intermediate boom 11, the tip boom 16, the arm 29 and the bucket 37, see FIGS. 3 and 4). ).

In such a state, the remote control valve 5
By operating 9, 79, 89, command signals 62s, 82s, and 92s from the controller 72 according to the relative position of each member constituting the offset type attachment, as in the hydraulic circuit shown in FIG. , Each regulating solenoid valve 62,
82 and 92 are controlled, and interference between each member constituting the offset attachment and the cab of the construction machine is suppressed.

On the other hand, the controller 72 controls the regulating solenoid valves 62, 82,
Command signal 6 to the solenoids 62a, 82a, 92a
When 2s, 82s, and 92s are not output, the operation lever 74a is tilted to position the spool of the selection switching valve 74 such that the other primary port in each circuit communicates with the secondary port. Set.

Accordingly, the remote control valve 59 for raising and lowering the boom is provided.
Is connected to one of the pilot ports 55a of the boom hoisting direction switching valve 55 by the pilot lines 63 and 101, the selection switching valve 74, and the pilot line 102.
To communicate through.

Further, one switching port of the arm rotation remote control valve 79 is connected to one pilot port 75a of the arm rotation direction switching valve 75 by the pilot line 83,
81, the selection switching valve 74, and the pilot line 112.

Further, one switching port of the offset remote control valve 89 is connected to one pilot port 85a of the offset directional switching valve 85 by a pilot line 93,
91, the selection switching valve 74, and the pilot line 122.

Therefore, when the operation levers 59a, 79a, 89a of the remote control valves 59, 79, 89 are tilted, the directional control valves 55, 75, 8 from the remote control valves 59, 79, 89.
5, hydraulic fluid pressure is applied to one of the pilot ports 55a, 75a, 85a, and the
The arm rotation cylinder 31 and the offset cylinder 22 operate.

In addition, check valves 104 and 84 that allow the flow of hydraulic oil from the secondary port to one of the primary ports are provided to the boom rising control solenoid valve 62 and the arm pulling control solenoid valve 82. Therefore, even if the command signals 62 s, 82 s, and 92 s are not output from the controller 72, the one pilot port 5
5a is a pilot line 102, a selection switching valve 74, a pilot line 100, a check valve 104, a pilot line 63.
Is connected to one switching port of the remote control valve 59 for raising and lowering the boom, and one pilot port 75a of the direction switching valve 75 for arm rotation is connected to the pilot line 112,
A remote control valve 79 for turning the arm through a selection switching valve 74, a pilot line 80, a check valve 84, and a pilot line 83.
Is connected to one of the switching ports.

Therefore, the command signal 62s,
When 82s is no longer output, before the selection switching valve 74 is switched, the standing angle of the main boom 1 can be reduced, or the tip of the arm 29 can be separated from the cab.

As described above, in the hydraulic circuit shown in FIG. 1, by operating the selection switching valve 74, one of the pilot ports 55a of the direction switching valves 55, 75, 85 from the remote operation valves 59, 79, 89 is operated. , 75a, and 85a, the hydraulic pressure of the working oil is directly applied to the position detecting sensors 67 to 7a.
Command signal 62 from the controller 72 due to damage to the
Even if s, 82s, and 92s are no longer output, the members constituting the offset attachment can be displaced to quickly move the construction machine from the work site to another location.

Further, since one of the pilot ports 55a, 75a, 85a of the directional control valves 55, 75, 85 and the remote control valves 59, 79, 89 are simultaneously connected by the collective switching of the selection switching valve 74, a plurality of ports are provided. The switching operation of the hydraulic circuit having the actuator can be performed extremely easily.

It should be noted that the hydraulic circuit of the present invention is not limited to only the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0101]

As described above, according to the hydraulic circuit of the present invention, the following various excellent effects can be obtained.

(1) In any of the hydraulic circuits according to the first and second aspects of the present invention, when the command signal is no longer output from the controller, the selection switching valve is operated so that The remote control valve is connected to the pilot port of the directional control valve by batch switching, and the fluid pressure of the working fluid is directly applied from the remote control valve to the pilot port of the directional control valve, so that a command signal is output from the controller. Even if it runs out, supply of the working fluid to the actuator can be ensured.

(2) Since the pilot port of each directional control valve and the remote control valve are simultaneously connected by the collective switching of the selection switching valve, the switching operation of the hydraulic circuit having a plurality of actuators can be performed extremely easily. Can be.

(3) In the hydraulic circuit according to the second aspect of the present invention, the flow of the working fluid from one pilot port of the directional switching valve connected to the solenoid valve to the remote control valve is checked. Therefore, the actuator can be returned to one direction before the selection switching valve is operated.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of an embodiment of a hydraulic circuit according to the present invention.

FIG. 2 is a conceptual diagram showing an example of a conventional hydraulic circuit.

FIG. 3 is a left side view of an example of the offset attachment.

FIG. 4 is a partially cutaway plan view of an intermediate boom portion of the offset attachment.

[Explanation of symbols]

 5 Boom hoisting cylinder (actuator) 22 Offset cylinder (actuator) 31 Arm turning cylinder (actuator) 50 Main pump 51 Pilot pump 55 Boom hoisting direction switching valve 55a, 55b Pilot port 59 Remote control valve for boom hoisting 62 Boom Rise control solenoid valve 62s Command signal 72 Controller 74 Selection switching valve 75 Arm rotation direction switching valve 75a, 75b Pilot port 79 Arm rotation remote control valve 82 Arm pulling restriction solenoid valve 82s Command signal 85 Offset direction switching valve 85a, 85b Pilot port 89 Remote control valve for offset 92 Solenoid valve for regulating leftward offset 92s Command signal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D003 AA01 AB03 AB04 BA07 BB11 CA06 DA03 DA04 DB05 3H082 AA03 BB17 CC02 DA02 DA19 DA22 DA23 DA37 DA46 DE05 EE02 3H089 AA60 BB15 BB28 CC11 DB45 DB48 DB63 EE17 EE18 EE12 FF03 JJ02

Claims (2)

[Claims] 1. A remote controller provided for each direction switching valve for switching the direction of a working fluid supplied from a main pump to an actuator, and capable of supplying a working fluid discharged from the pilot pump to a pilot port of the direction switching valve. A hydraulic circuit having an operation valve and an electromagnetic valve provided between the remote operation valve and at least one pilot port of the direction switching valve and controlled by a command signal output from a controller; A state in which the remote control valve is connected to the pilot port via the solenoid valve between the remote control valve and at least one pilot port of the directional control valve, or the remote control valve is connected to the pilot port without the solenoid valve A hydraulic circuit characterized in that a selection switching valve is provided which can be collectively switched to a state in which the pressure is changed. 2. The hydraulic circuit according to claim 1, wherein a check valve capable of permitting the flow of the working fluid from one pilot port of the directional control valve to the remote control valve is provided in a predetermined solenoid valve.