JPS6316709Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a hydraulic circuit for a working vehicle such as a crane vehicle or a digging pole erecting vehicle.

Generally, the above-mentioned work vehicle has a multi-stage boom and winch that extend and retract and raise and lower.
Figure 1 shows an example of such a work vehicle.
Reference numeral 1 denotes a turntable rotatably supported on a vehicle body 2, and a multistage boom 3 is supported on this turntable 1 by an erecting cylinder 4 so as to be erectable. The multi-stage boom 3 is composed of an outer boom 5 and an inner boom 6, and the inner boom 6 is extended and contracted by protruding from or retracting from the outer boom 5 by a telescopic cylinder (not shown). A hook 9 is suspended from the tip of the inner boom 6 by a wire rope, and the wire rope is hoisted and lowered by a winch 7 equipped with a hydraulic motor 8 to raise and lower the hook 9. . In this device, the undulating cylinder 4, the telescopic cylinder, and the hydraulic motor 8 are controlled by switching operations of individual switching valves. However, when raising and lowering or extending and contracting the multi-stage boom 3,
Since the winch 7 must also be operated in conjunction with the operation of the multi-stage boom 3, there is a problem in that the operation becomes complicated and erroneous operation is likely to occur. For example, if the winch 7 is hoisted at the same time as the multi-stage boom 3 is extended, the wire rope may break, and if the winch 7 is not lowered at the same time as the multi-stage boom 3 is lowered, the wire may overwind. or

This idea was created in view of the above-mentioned problems, and includes a hydraulic cylinder that extends and retracts the boom, a hydraulic cylinder that raises and lowers the boom, and a hydraulic motor for the winch that hoists and lowers the hook suspended from the tip of the boom. In a hydraulic circuit for a working vehicle, the hydraulic circuit includes an inlet of a hydraulic motor into which pressure oil flows when hoisting the hook, a rod side of a hydraulic cylinder that extends and contracts the boom, and a head side of the hydraulic cylinder that raises and lowers the boom. A second pipe connects the inlet and outlet of the hydraulic motor into which pressure oil flows when lowering the hook, the head side of the hydraulic cylinder that extends and contracts the boom, and the rod side of the hydraulic cylinder that raises and lowers the boom. connected, and in the middle of the first and second piping, the first,
An on-off valve that opens and closes both the second piping is provided, and a pilot check valve that only allows flow from the hydraulic cylinder to the on-off valve is provided in the first and second piping between the on-off valve and the hydraulic cylinder that extends and retracts the boom. The pilot passages of these pilot check valves are connected to the second and first piping, respectively, between the hydraulic cylinder that extends and retracts the boom and the pilot check valve, and the pilot passages of these pilot check valves are connected to the second and first pipes, respectively, between the hydraulic cylinder that extends and retracts the boom and the hydraulic cylinder that raises and lowers the boom. 1st and 2nd between
Each piping is provided with a pilot check valve that allows flow only from the hydraulic cylinder to the on-off valve, and the pilot passages of these pilot check valves are connected to the second and second valves between the hydraulic cylinder that raises and lowers the boom and the pilot check valve. The purpose is to solve the above problems by connecting them to one pipe.

This invention will be explained below based on the drawings.

FIG. 2 is a diagram showing an embodiment of this invention.
First, the configuration will be explained, but the same parts as described above will be given the same reference numerals in the drawings, and detailed explanation will be omitted.
11 is an oil tank, and 12 is a pump driven by the prime mover 13 to pressurize and discharge oil in the oil tank 11. The main pipe 14 has one end connected to the discharge port of the pump 12 and the other end connected to the oil tank 11. A hydraulic motor 8 of the winch 7, a telescopic cylinder 15 of the boom 3, and a lifting cylinder 4 of the boom 3 are installed in the middle of the main pipe 14.
Manual 6-port 3-position switching valves 16, 17, and 18 are respectively provided to control the pressure oil discharged from the pump 12 when these switching valves 16, 17, and 18 are in the neutral position. returns directly to the oil tank 11. 19, 20, 2
Reference numeral 1 designates a return pipe whose one end is connected to switching valves 16, 17, and 18, and the other end is connected to the main pipe 14, respectively. One outlet 8a of the hydraulic motor 8 and the switching valve 16 are connected by a first winch pipe 22, and the other outlet 8b and the switching valve 16 are connected by a second winch pipe 23.
When pressure oil flows into the hydraulic motor 8 through the winch piping 22 and the inlet 8a, the winch 7 is lowered, and the second winch piping 23 and the inlet 8b are lowered.
When pressure oil flows into the hydraulic motor 8 via the hydraulic motor 8, the winch 7 is hoisted up. Further, the rod 15a side of the telescopic cylinder 15 and the switching valve 17 are connected to the first telescopic pipe 2.
4, the head 15b side of the telescoping cylinder 15 and the switching valve 17 are connected by the second telescoping pipe 25, and when pressure oil flows into the rod side of the telescoping cylinder 15 through the first telescoping pipe 24, the boom 3 contracts. The telescopic cylinder 15 is connected via the second pipe 25.
When pressure oil flows into the head side of the boom 3, the boom 3 is extended. Further, the rod 4a side of the undulation cylinder 4 and the switching valve 18 are connected by a first undulation pipe 26, and the head 4b side of the undulation cylinder 4 and the switching valve 18 are connected by a second undulation pipe 27, and the first undulation pipe 26 When pressure oil flows into the rod side of the undulation cylinder 4 through the undulating cylinder 4, the boom 3 is lowered, and when pressure oil flows into the head side of the undulation cylinder 4 through the second undulation pipe 27, the boom 3 rises. In addition, 28, 29, 3
0 is the second winch pipe 23, the second expansion pipe 25,
These are counterbalance valves each provided in the middle of the second undulating pipe 27. The hydraulic circuit of a conventional work vehicle had the configuration as described above, but in the present invention, it has been improved as described below. That is, the outflow inlet 8b of the hydraulic motor 8 and the rod 15a side of the telescopic cylinder 15 are connected by the first pipe 31 for the telescopic cylinder 15, and the outflow inlet 8a of the hydraulic motor 8 and the head 15b side of the telescopic cylinder 15 are connected. They are connected by a second pipe 23 for the telescopic cylinder 15. Further, the inlet 8b of the hydraulic motor 8 and the head 4b side of the luffing cylinder 4 are connected via a first pipe 31, and the hydraulic motor 8 is connected via a second pipe 32 with a first pipe 34 for the luffing cylinder 4. The outflow inlet 8a and the rod 4a side of the undulation cylinder 4 are connected by a second pipe 33 for the undulation cylinder 4. A manual, 4-port, 2-position type on-off valve 35 is provided midway between the first and second pipes 31 and 32. The first and second pipes 31 and 32 between the on-off valve 35 and the telescopic cylinder 15 are provided with pilot check valves 36 and 37 that allow only flow from the telescopic cylinder 15 toward the on-off valve 35. The valves 36 and 37 are connected to pilot passages 38 and 3 that connect the second and first pipes 32 and 31 to the pilot check valves 36 and 37 when the pressure in the second and first pipes 32 and 31 becomes high.
It is opened by the pressure transmitted through 9. Moreover, the first one between the on-off valve 35 and the undulating cylinder 4,
The second pipes 34 and 33 have check valves 4 that allow only flow from the undulation cylinder 4 toward the on-off valve 35.
0,41 are provided, and these check valves 40,
Reference numeral 41 denotes a pilot passage 4 that connects the first and second pipes 34 and 33 with the check valves 40 and 41 when the pressure inside the first and second pipes 34 and 33 becomes high pressure.
2, 43 opens.

Next, the effect will be explained.

When operating the winch 7, extending and contracting the boom 3, and raising and lowering the boom 3 independently, the on-off valve 35 is kept in the closed position shown in FIG. 2. And winch 7
To raise or lower the boom 3, move the switching valve 16 to the left or right in FIG. 2, and to extend or retract the boom 3, move the switching valve 17 to the left or right to raise or lower the boom 3. When it is placed down, the switching valve 18 is moved to the left or right. Next, when the boom 3 is to be extended when a load is hung on the hook 9 of the winch 7, for example, after switching the on-off valve 35 to the open position, the switching valve 17 is moved to the left as shown in FIG. let As a result, the pressure oil flows into the head 15b side of the telescopic cylinder 15 and the boom 3
expands. At this time, high pressure is transmitted to the check valve 36 via the pilot passage 38, and the check valve 36 is opened. Also, at this time, the pressure oil expands the check valve 37 and flows into the hydraulic motor 8 from the outflow port 8a via the second pipe 32 and the on-off valve 35, rotates the hydraulic motor 8, and lowers the winch 7. Let's do it. The return oil coming out of the inlet 8b of the hydraulic motor 8 is mixed with the return oil coming out of the rod 15a side of the telescopic cylinder 15 via the first piping 31 on-off valve 35 and the check valve 36 which has been opened as described above. The oil merges and flows into the first telescopic pipe 24, and finally returns to the oil tank 11. in this way,
Since the winch 7 is automatically lowered in conjunction with the extension of the boom 3, the operation is extremely simple and the wire will not be cut. Furthermore, when the boom 3 is retracted and when the boom 3 is raised or lowered, the hydraulic motor 8 rotates in conjunction with the operation of the telescopic cylinder 15 and the raising and lowering cylinder 4, and the winch 7 is hoisted and lowered in the same manner. , wire cutting,
Overwinding can be prevented.

As explained above, according to this invention, the hydraulic motor rotates automatically in conjunction with the extension/contraction and undulation cylinders, so the winch lowers and hoists in line with the boom's extension, contraction, and undulation. can be moved parallel to the boom, making operation extremely easy and preventing wire breakage and overwinding.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a conventional working vehicle, and FIG. 2 is a circuit diagram showing an embodiment of the hydraulic circuit of the working vehicle according to this invention. 3... Boom, 4... Lifting cylinder, 7... Winch, 8... Hydraulic motor, 15... Telescopic cylinder, 31, 34... First piping, 32, 33... Second piping, 35... Opening/closing Valve, 36, 37, 40, 4
1... Pilot check valve, 38, 39, 4
2,43...Pilot passage.

Claims (1)

[Scope of utility model registration request] In a hydraulic circuit for a working vehicle, the hydraulic circuit includes a hydraulic cylinder that extends and contracts the boom, a hydraulic cylinder that raises and lowers the boom, and a hydraulic motor for a winch that hoists and lowers a hook suspended from the tip of the boom. A first pipe connects the inlet and outlet of the hydraulic motor into which pressure oil flows during hoisting, the rod side of the hydraulic cylinder that extends and retracts the boom, and the head side of the hydraulic cylinder that raises and lowers the boom. A second pipe connects the inlet and outlet of the hydraulic motor into which oil flows, the head side of the hydraulic cylinder that extends and contracts the boom, and the rod side of the hydraulic cylinder that raises and lowers the boom, and connects the oil in the middle of the first and second pipes. An on-off valve is provided to open and close both the first and second pipes, and further,
The first and second piping between the on-off valve and the hydraulic cylinder that extends and retracts the boom are each provided with a pilot check valve that allows flow only from the hydraulic cylinder toward the on-off valve, and the pilot passage of these pilot check valves is a second one between the hydraulic cylinder that extends and retracts the boom and the pilot check valve;
The first and second piping, which are connected to the first piping and between the on-off valve and the hydraulic cylinder that raises and lowers the boom, are each provided with a pilot check valve that allows flow only from the hydraulic cylinder to the on-off valve. A hydraulic circuit for a working vehicle, wherein a pilot passage of a pilot check valve is connected to second and first pipes, respectively, between a hydraulic cylinder for raising and lowering a boom and the pilot check valve.