JP3469279B2 - Hydraulic circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit. [0002] 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. Reference numeral 1 denotes a main boom, and a base end of the main boom 1 is provided on a rear upper portion of a bracket 3 provided on the revolving unit 2 of the construction machine main body with a pin 4 extending substantially horizontally in the width direction of the revolving unit 2. Is pivoted by [0005] Reference numeral 5 denotes a boom raising / lowering cylinder. The base end of a cylinder body 6 of the boom raising / lowering cylinder 5 is pivotally attached to a lower front portion of the bracket 3 by a pin 7 parallel to the pin 4. The tip of the piston rod 8 of the boom raising / lowering cylinder 5 is pivotally connected to a bracket 9 provided at the tip of the main boom 1 by a pin 10 parallel to the pin 4. Reference numeral 11 denotes an intermediate boom.
The base end of the main boom 1 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. Reference numeral 16 denotes a tip boom.
6 is pivotally attached to the tip of the intermediate boom 11 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. Reference numeral 13 denotes a link bar.
Reference numeral 3 is disposed on the left side of the intermediate boom 11 so as to be substantially parallel to the intermediate boom 11. The base end of the link bar 13 is attached to a bracket 14 provided at 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. Reference numeral 22 denotes an offset cylinder, which is arranged 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 Reference numeral 29 denotes an arm. The base end of the arm 29 is pivotally connected to the distal end of the distal end boom 16 by a pin 30 parallel to the pin 4. Reference numeral 31 denotes an arm rotation cylinder. The base end of the cylinder body 32 of the arm rotation cylinder 31 is pivotally attached to the cylinder support portion 18 of the distal end boom 16 by a pin 33 parallel to the pin 4. The distal end of the piston rod 34 of the arm rotation cylinder 31 is pivotally connected to a bracket 35 provided at the base end of the arm 29 by a pin 36 parallel to the pin 4. Reference numeral 37 denotes a bucket, and a bracket 38 provided on the back surface of the bucket 37 is pivotally connected to the tip of the arm 29 by a pin 39 parallel to the pin 4. Reference numeral 40 denotes a bucket rotating cylinder. The base of the cylinder body 41 of the bucket rotating cylinder 40 is a bracket 4 provided at the base of the arm 29.
2 is pivotally connected 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 moves forward or backward, the main boom 1
Undulates. When operating hydraulic pressure is applied to the offset cylinder 22 from the main hydraulic pump, the intermediate boom 11 swings right and left around 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 from the main hydraulic pump to the bucket rotating cylinder 40, 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 the 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 does not have a closed cab surrounding a driver's seat such as 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 excavation claw of the bucket 37 interferes with the cab depending on the conditions of the undulating angle of the intermediate boom with respect to the main boom 1, the swing angle of the arm 29 with respect to the tip boom 16, and the swing angle of the bucket 37 with respect to the arm 29. Or may get inside the cab. Therefore, for the purpose of protecting the driver, the hydraulic circuit for driving the offset type attachment is provided with an interference prevention 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. Reference numeral 50 denotes a main pump, and reference numeral 51 denotes a pilot pump. Both pumps 50 and 51 are driven by the same engine 52. Reference numeral 53 denotes an oil tank.
Are connected to the oil suction ports of the pumps 50 and 51 via a hydraulic oil suction pipe 54 and pipes 55a and 55b, respectively. Reference numeral 56 denotes a main control valve (a pilot pressure switching type three-position switching valve).
6 is connected to the oil discharge port of the main pump 50 via a hydraulic oil supply line 57, and the tank port and the bypass port are connected to the oil tank 53 via a hydraulic oil return line 58. It is connected. The two switching ports of the main control valve 56 are connected to the two fluid chambers of the boom hoist cylinder 5 via pipes 61a and 61b, respectively. A main relief valve 59 has an inlet port connected to the hydraulic oil supply line 57 and an outlet port connected to the hydraulic oil return line 58. The main control valve 56 is normally set at a neutral position where the inlet port is blocked by an elastic body such as a spring, and the pilot ports 60a, 60
When a fluid pressure is applied to one of the switching ports b, the pump is set to a switching position communicating with one of the switching ports. Reference numeral 62 denotes a hydraulic remote control valve (manual operation type 2).
Directional pilot pressure switching valve), and the hydraulic remote control valve 6
The second pump port is connected to the oil discharge port of the pilot pump 51 via a pilot line 63, and the tank port is connected to the oil tank 53 via a pilot line 64. Reference numeral 65 denotes a primary pilot pressure setting relief valve. The inlet port of the primary pressure setting relief valve 65 is connected to the pilot line 63, and the outlet port is connected to the hydraulic oil return line 58. Reference numeral 66 denotes an electromagnetic proportional pressure reducing valve (2 of an electromagnetic switching type).
The pump port of the electromagnetic proportional pressure reducing valve 66 is connected to one of the switching ports of the hydraulic remote control valve 62 via a pilot line 67, and the tank port is connected to the pilot line 68. The hydraulic oil return line 58 is connected to the hydraulic oil return line 58 through the above-described operation. When the solenoid 69 is not excited, the solenoid proportional pressure reducing valve 66 is set so that the pump port is blocked by an elastic body such as a spring and the switching port communicates with the tank port. (See FIG. 2) Also, when the solenoid 69 is excited, the position is set such that the pressure value of the fluid flowing from the inlet port to the switching port increases in proportion to the current value supplied to the solenoid 69. Is performed. 70a and 70b are pilot pipelines,
The pilot line 70a connects the switching port of the electromagnetic proportional pressure reducing valve 66 to one of the pilot ports 60a of the main control valve 56.
Connects the other switching port of the hydraulic remote control valve 62 to the other pilot port 60b of the main control valve 56. Reference numerals 71a to 71d denote position detecting sensors such as potentiometers.
Angle of the main boom 1 with respect to
b is the swing angle of the intermediate boom 11 with respect to the main boom 1,
The position detection sensor 71c indicates the rotation angle of the arm 29 with respect to the tip boom 16 and the position detection sensor 71d indicates the arm 2
The rotation angle of the bucket 37 with respect to the main boom 9, the intermediate boom 11, the tip boom 16, the arm 29, and the bucket 37 are detected as shown in FIG.
And FIG. 4). Reference numeral 75 denotes a data storage, which 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, the main storage The swing angle of the intermediate boom 11 with respect to the boom 1, the pivot angle of the arm 29 with respect to the tip boom 16, the bucket 3 with respect to the arm 29
7 is stored as a data signal 76. Reference numeral 72 denotes a controller. The controller 72 is based on the position detection signals 73a to 73d output from the position detection sensors 71a to 71d and the data signal 76 stored in the data storage 75. A command signal 74 is output to a solenoid 69 of the electromagnetic proportional pressure reducing valve 66. The controller 72 includes a position detection sensor 71
a to 71d are damaged or the position detection sensor 7
The electromagnetic proportional pressure reducing valve 66 is used when the cable connecting the controller 72 to the controller 72 is disconnected and the position detection signals 73a to 73d are not input to the controller 72 or when the controller 72 itself breaks down. Command signal 7 to the solenoid 69
4 is not output. In the hydraulic circuit shown in FIG. 2, when the construction machine is running, the position detection sensors 71a to 71a
1d to the controller 72 from the position detection signals 73a-73.
The main boom 1, the intermediate boom 11, and the tip boom which form an offset attachment from the position detection signals 73 a to 73 d and the data signal 76 stored in the data storage 75 in the controller 72. 1
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, which constitute the offset type attachment,
6. If the respective members do not interfere with the cab of the construction machine even when the arm 29, the bucket 37, etc. are displaced to some extent, the controller 69 controls the solenoid 69 of the electromagnetic proportional pressure reducing valve 66. A command signal 74 having a large current value is output, and the position is set so that the pressure value of the fluid flowing from the inlet port of the electromagnetic proportional pressure reducing valve 66 to the switching port becomes maximum. In such a state, when the hydraulic remote control valve 62 is operated to make the pump port of the hydraulic remote control valve 62 communicate with one of the switching ports, the hydraulic pressure of the hydraulic oil discharged from the pilot pump 51 is reduced by the pilot pressure. Line 6
3. It is provided to the pilot port 60a of the main control valve 56 via the hydraulic remote control valve 62, the pilot line 67, the electromagnetic proportional pressure reducing valve 66, and the pilot line 70a. As a result, the pump port of the main control valve 56 communicates with the switching port connected to the line 61a of the boom hoisting cylinder 5, and the operating oil discharged from the main pump 50 is supplied to the operating oil supply line. 57, main control valve 5
6. The fluid is supplied to the head-side fluid chamber of the boom hoist cylinder 5 through the conduit 61a, and the amount of protrusion of the piston rod 8 (see FIG. 3) increases, so that the hoist angle of the main boom 1 increases. On the other hand, 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. Then, the current value of the command signal 74 output from the controller 72 to the solenoid 69 of the electromagnetic proportional pressure reducing valve 66 decreases. Accordingly, the pressure value of the hydraulic oil flowing from the inlet port of the electromagnetic proportional pressure reducing valve 66 to the switching port decreases, and the inflow of the hydraulic oil supplied from the main pump 50 to the head-side fluid chamber of the boom hoist cylinder 5. The displacement is reduced, and the displacement speed of the main boom 1 is reduced. When the bucket 37 is located near the cab, the controller 72 does not output the command signal 74 to the solenoid 69 of the electromagnetic proportional pressure reducing valve 66, and the electromagnetic proportional pressure reducing valve 66 is pumped by an elastic body such as a spring. The port is blocked so that the switching port communicates with the tank port, so that the hydraulic pressure of the hydraulic oil discharged from the pilot pump 51 is not applied to the pilot port 60 a of the main control valve 56. As a result, the main control valve 56 is set to the neutral position, the hydraulic oil discharged from the main pump 50 is no longer supplied to the head-side fluid chamber of the boom raising / lowering cylinder 5, and the displacement of the main boom 1 is stopped and the cab is stopped. Interference 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. 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 71a to 71a are provided.
When the command signal 74 is no longer output from the controller 72 to the solenoid 69 of the electromagnetic proportional pressure reducing valve 66 due to damage such as 1d, the hydraulic oil is supplied from the electromagnetic proportional pressure reducing valve 66 to the pilot port 60a of the main control valve 56. The fluid pressure cannot be applied. For this reason, it was not possible to move the construction machine from the work site to another place quickly by displacing the offset type attachment. The present invention has been made in view of the above-described circumstances, and has a fluid control device in which an electromagnetic valve driven according to a command signal output from a controller is provided between a pilot port of a main control valve and a hydraulic remote control valve. It is an object of the present invention to supply a working fluid to a pilot port of a main control valve even when a command signal is not output from a controller in a pressure circuit. In order to achieve the above object, according to the present invention, an operation in which a pilot pump discharges to a pilot port of a main control valve for switching a direction of a working fluid supplied from a main pump to an actuator. It has a hydraulic remote control valve capable of supplying a fluid, and an electromagnetic valve provided between the hydraulic remote control valve and at least one of the pilot ports of the main control valve and controlled by a command signal output from a controller. In the hydraulic circuit,
Between the hydraulic remote control valve and the pilot port of the main control valve, there is provided a selection switching valve for communicating the hydraulic remote control valve with the pilot port via an electromagnetic valve or not via the electromagnetic valve. In the hydraulic circuit of the present invention, by operating the selection switching valve, the hydraulic remote control valve and the pilot port of the main control valve communicate with each other without the intermediary of the solenoid valve. When operated, the working fluid discharged from the pilot pump is supplied to the pilot port of the main control valve without being affected by the command signal output from the controller. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a hydraulic circuit according to the present invention. The basic configuration of the hydraulic circuit is the same as that shown in FIG. 2, and the portions denoted by the same reference numerals as those in FIG. It represents the same thing. In this embodiment, a selection switching valve (manually operated two-position switching valve) 77 is provided between the hydraulic remote control valve 62 and the pilot port 60a of the main control valve 56. One inlet port of the selection switching valve 77 is connected to a switching port of the electromagnetic proportional pressure reducing valve 66 via a pilot line 78, and the other inlet port is connected to one switching port of the hydraulic remote control valve 62. Pilot line 6
7 is connected via a pilot line 79, and the outlet port is connected to one pilot port 60 a of the main control valve 56 via a pilot line 80. The selection switching valve 77 is normally set so that one inlet port and one outlet port communicate with each other and the other inlet port is blocked (see FIG. 1). When the handle 81 is operated, the position is set so that the other inlet port communicates with the outlet port and the one inlet port is blocked. Hereinafter, the operation of this embodiment will be described. When the position detection sensors 71a to 71d are not damaged and the command signal 74 is output from the controller 72 to the solenoid 69 of the electromagnetic proportional pressure reducing valve 66 as usual, the selection switching valve 77 is switched to the selection switching state. The position is set so that one inlet port and outlet port of the valve 77 communicate with each other and the other inlet port is blocked. At this time, in the controller 72, the position detection signals 73a to 73d output from the respective position detection sensors 71a to 71d to the controller 72 and the data storage 75
The main boom 1 and the intermediate boom 1 forming an offset type attachment based on the data signal 76 stored in the
1. The positional relationship between the members such as the tip boom 16, the arm 29, and the bucket 37 and the cab of the construction machine is required. When the hydraulic remote control valve 62 is operated in such a state, the electromagnetic proportional pressure reducing valve 66 is controlled by the command signal 74 output from the controller 72, similarly to the hydraulic circuit shown in FIG. The interference between each member constituting the offset type attachment and the cab is suppressed. On the other hand, when the command signal 74 is not output from the controller 72 to the solenoid 69 of the electromagnetic proportional pressure reducing valve 66 due to damage to the position detection sensors 71a to 71d, the switching handle of the selection switching valve 77 is switched. By operating 81, the other input port and the output port of the selection switching valve 77 are communicated with each other to block one of the input ports. When the selection switching valve 77 is set as described above,
One switching port of the hydraulic remote control valve 62 and one pilot port 60a of the main control valve 56 are connected to the pilot line 67, the pilot line 79, the selection switching valve 77,
It communicates via a pilot line 80. Therefore, by operating the hydraulic remote control valve 62, the main control valve 5
The fluid pressure of the working oil can be applied to one of the pilot ports 60a. As described above, in this embodiment, by operating the selection switching valve 77, the hydraulic remote control valve 62 to the one pilot port 60a of the main control valve 56 are operated.
Since the fluid pressure of the hydraulic oil can be directly applied to the construction machine, even if the command signal 74 is not output from the controller 72 due to the damage of the position detection sensors 71a to 71d, the construction machine can be quickly moved by displacing the offset type attachment. Can be moved from the work site to another location. The embodiment shown in FIG. 1 relates to the raising operation portion of the hydraulic circuit of the boom raising / lowering cylinder 5 shown in FIG. 3, but the cab of the construction machine and each member constituting the offset type attachment are connected to each other. In order to completely prevent the interference, in addition to the raising operation of the hydraulic circuit of the boom raising and lowering cylinder 5, the pulling operation of the hydraulic circuit of the arm rotating cylinder 31 (see FIG. 3) for performing the pulling operation of the arm 29 is performed. The components and the push-operation components of the hydraulic circuit of the offset cylinder 22 (see FIG. 4) for shifting the tip boom 16 to the left have substantially the same configuration as that shown in FIG. At this time, if the switching handle 81 of each selection switching valve 77 can be operated collectively, the switching operation of the hydraulic circuit can be performed extremely easily. On the other hand, the switching handle 8 of each selection switching valve 77
1 can be operated individually, the specific cylinder for operating the offset type attachment can be controlled by the controller 7.
2 can be operated independently. It should be noted that the hydraulic circuit of the present invention is not limited to only the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention. As described above, according to the hydraulic circuit of the present invention, by operating the selection switching valve, the hydraulic remote control valve and the pilot port of the main control valve do not pass through the solenoid valve. It is possible to supply the working fluid to the pilot port of the main control valve even if the command signal is no longer output from the controller, so that the working fluid can be supplied to the actuator even when the controller fails. An excellent effect that the supply is secured can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram showing one embodiment of a hydraulic circuit of the present invention. FIG. 2 is a conceptual diagram illustrating 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. [Description of Signs] 5 Boom hoisting cylinder (actuator) 50 Main pump 51 Pilot pump 56 Main control valve 60a Pilot port 62 Hydraulic remote control valve (hydraulic remote control valve) 66 Electromagnetic proportional pressure reducing valve (electromagnetic valve) 72 Controller 74 Command Signal 77 selection switching valve

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-151603 (JP, A) JP-A-52-22070 (JP, A) JP-A-2-173403 (JP, A) JP-A-1- 141207 (JP, A) JP-A-2-108732 (JP, A) JP-A-64-41498 (JP, A) JP-A-60-11704 (JP, A) JP-A-61-153003 (JP, A) 55-173704 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F15B 20/00 F15B 11/08 E02F 9/22

Claims (1)

(57) [Claim 1] A hydraulic remote controller capable of supplying a working fluid discharged from a pilot pump to a pilot port of a main control valve for switching a direction of a working fluid supplied from a main pump to an actuator. In a hydraulic circuit having a valve and an electromagnetic valve provided between the hydraulic remote control valve and at least one of the pilot ports of the main control valve and controlled by a command signal output from a controller,
A selection switching valve is provided between the hydraulic remote control valve and the pilot port of the main control valve to allow the hydraulic remote control valve and the pilot port to communicate with each other via an electromagnetic valve or without the electromagnetic valve. Characteristic hydraulic circuit.