JPH0357034B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The oil discharged from the first hydraulic pump is supplied in a divided manner to each winch motor control throttle switching valve of the conventional two-pump type compound winch circuit via the first flow rate control valve. Each of the throttle switching valves is provided with a valve mechanism that blocks the unload circuit connected to the second hydraulic pump by displacement of the spool after the throttle is substantially fully opened, and one throttle switching valve is switched to its full limit. When the unload circuit is blocked, the oil discharged from the second hydraulic pump flows through the check valve to the first hydraulic pump.
The invention in which oil is combined with the discharge oil of a hydraulic pump and supplied to the first flow control valve is disclosed in Japanese Patent Application Laid-Open No. 57-203693.
As shown in the publication, when driving piles by hanging a vibrating pile driver on the main winding drum of this winch and suspending piles (sheet piles) on the winch's main winding drum, the main winding drum and When simultaneously driving the auxiliary winding drums, if the throttle switching valve connected to the regulated flow rate outlet of the first flow rate control valve is switched to its full limit, there is a risk that the flow rate of the winch motor connected to the excess flow rate outlet may become insufficient. This drawback is particularly noticeable when the throttle switching valve connected to the regulated flow rate outlet controls the main winding drum drive winch motor.

The present invention addresses this problem by maintaining a constant pressure difference between the first hydraulic pump 1 and the first throttle switching valve 3 for controlling the first winch motor 2. A second flow control valve 4 for controlling the second winch motor 5 and a second flow control valve 7 are connected to the surplus flow outlet of the first flow control valve. connected so as to maintain a constant pressure difference before and after the throttle switching valve, and the first,
In a control device for a double-barrel winch, each of the second throttle switching valves is provided with a valve mechanism that blocks the unload circuit 9 connected to the second hydraulic pump 8 by spool displacement after the throttle is substantially fully opened. Second
A first check valve 10 is provided between the hydraulic pump 8 and the inlet of the first flow control valve 4 to close the working hydraulic pressure by the second winch motor 5, and a first check valve 10 is provided between the second hydraulic pump and the inlet of the second flow control valve 7. The second check valves 11 which are closed by the discharge pressure oil of the second hydraulic pump are connected between them, and the pilot oil chambers of the second check valves 11 are connected to the tank by being switched by the working oil pressure of the second winch motor 5. The present invention is characterized in that a switching valve 12 connected to the second check valve is inserted into the second check valve closed oil passage.

FIG. 1 shows an embodiment of the present invention applied to a double-barrel winch for a truck crane, in which the first winch motor 2 is for driving the main winding drum, the second winch motor 5 is for driving the auxiliary winding drum, and the first winch motor 5 is for driving the auxiliary winding drum. The switching valve 3 controls the main winding hydraulic motor circuit 13, and the second throttle switching valve 6 controls the auxiliary winding hydraulic motor circuit 14. As before, counterbalance valves 34 and 35 are incorporated into each hydraulic motor circuit 13 and 14 for lowering and stopping the suspended load. The first and second hydraulic pumps 1 and 8 are of a fixed displacement type or a variable displacement type, and are simultaneously driven by an engine 16 together with a hydraulic pump 15 for driving a swing motor of a crane swivel base.

The first and second throttle switching valves 3 and 6 increase the amount of displacement of the spool of the throttle switching valve that blocks the pressure port in the neutral position A shown in the figure, respectively, and move the throttle opening to both positions B and D where the throttle opening can be adjusted. These are spring center type valves having positions C and E that block the unloading circuit 9 by the displacement of the spool after the throttle V is fully opened, respectively, and are connected to the discharge port of the first hydraulic pump 1 via an oil passage 17. The regulated flow rate outlet 4a of the first flow rate control valve 4 is connected to the pressure port of the first throttle switching valve 3. The first flow control valve 4 is
Throttle control is performed in proportion to the difference between the pilot oil pressure taken out from the regulated flow outlet side via the oil passage 18 and the pilot oil pressure taken out from the high pressure side oil passage of the hydraulic motor circuit 13 via the shuttle valve 19 and the oil passage 20. The pressure compensation valve on which the spool slides maintains the pressure difference before and after the first throttle switching valve 3 constant regardless of load fluctuations.

A second flow rate control valve 7 is connected to the surplus flow rate outlet 4b of the first flow rate control valve 4 via an oil passage 21, and a regulated flow rate outlet 7a of the second flow rate control valve is connected to the preset of the second throttle switching valve 6. The shear port and its surplus flow outlet 7b are connected to the tank T via an oil passage 22, respectively. The second flow control valve 7 also receives pilot oil pressure taken out from its regulated flow outlet side via the oil passage 23 and pilot oil pressure taken out from the high pressure side oil passage of the hydraulic motor circuit 14 via the shuttle valve 24 and the oil passage 25. This is a pressure compensating valve in which a throttle control spool slides in proportion to the difference between the two throttle control valves 6 and 6, and the pressure difference across the second throttle switching valve 6 is always maintained constant regardless of changes in load.

26 is a hydraulic circuit including a directional switching valve that can selectively connect a derrick cylinder or a boom telescopic cylinder to the discharge port of the second hydraulic pump 8; 6 is in the neutral position, the unload circuit 9 is conductive and the second hydraulic pump 8 is operated with no load.
When directional control valve 6 is switched, unload circuit 9
is blocked.

27 is an oil passage connected to the unloading circuit 9 between the hydraulic circuit 26 and the first throttle switching valve 3, and a first non-return check is provided in the oil passage 28 connecting between the oil passage 27 and the oil passage 17. A second check valve 11 is inserted into the oil passage 29 that connects the valve 10 and the oil passages 27 and 21, respectively. The second check valve 11 is connected to the pilot oil chamber 1.
1a is connected to the oil passage 2 via the second check valve blockage oil passage 30.
A switching valve 12 is connected to the oil passage 30 and has a normal position shown in the figure that conducts the oil passage and a switching position that connects the pilot oil chamber 11a to the tank T.
is inserted. The pilot oil passage 25a that closes the first check valve 10 and the pilot oil passage 25b that switches the switching valve 12 to the switching position are the second flow control valve 7.
The second
When a suspended load or the opening hydraulic pressure of the counterbalance valve 35 acts on the winch motor 5, both valves 10 and 12 are pilot operated by the operating hydraulic pressure.

Throttle valves 31 and 32 are inserted into the oil passages 25a and 30, respectively, in order to cope with sudden changes in pilot oil pressure;
Reference numeral 33 indicates a throttle valve connected in parallel with the second check valve 11 in the oil passage 29, and when the discharge hydraulic pressure of the second hydraulic pump 8 acts on the oil passage 27, the throttle valve 33 restricts this to the second restriction valve. By supplying a small amount to the switching valve 6, even when the surplus flow discharged by the first flow control valve 4 is extremely small, pilot oil pressure is generated in the oil passage 25 to enable the operation of the first check valve 10 and the switching valve 12. .

According to the above configuration, when all the switching valves 3, 6, etc. including the hydraulic circuit 26 are in the neutral position, the suspended load is supported by the counterbalance valves 34, 35, so each flow control valve 4, oil passage 20 to 7,
Since the pilot oil pressures 25 and 25 are approximately zero, the oil discharged from the first hydraulic pump 1 is sequentially unloaded into the tank T via the surplus flow outlets 4b and 7b of the first and second flow control valves 4 and 7, Further, the oil discharged from the second hydraulic pump 8 is also unloaded by the unload circuit 9, and both hydraulic pumps are operated under no load.

In order to hoist or lower the load using the main hoisting drum,
When only the first throttle switching valve 3 is switched to the B position or the N position, the first flow control valve 4 maintains the pressure difference before and after the throttle switching valve 3 constant regardless of the opening degree of the throttle V. Therefore, the first pump discharge oil at the pressure corresponding to the magnitude of the load is supplied to the outlet 4a of the throttle switching valve 3.
The flow rate can be easily controlled by adjusting the opening of the throttle V, and the first winch motor 2 is driven at a low speed to discharge the surplus flow rate to the tank from the outlet 4b. In this case, the first check valve 10 is closed by its own valve closing spring to prevent the discharge hydraulic pressure of the hydraulic pump 1 from flowing back into the unload circuit 9 via the oil passages 28 and 27.

When the first throttle switching valve 3 is further switched to the C or H position from this state, the unload circuit 9 is blocked by the throttle switching valve, and the discharge hydraulic pressure of the second hydraulic pump 8 acts on the oil passage 27. However, in this case, the pilot oil pressure does not act on the oil passages 25a and 25b, and the switching valve 12 is maintained at the normal position shown in the figure, so the second check valve 11 is closed by the oil pressure of the oil passage 27, and the second The first check valve 10 opens and the pressure oil discharged from the second hydraulic pump 8 is supplied to the oil passage 17. That is, since the discharge amounts of the first and second hydraulic pumps 1 and 8 are combined and supplied to the first flow rate control valve 4, the first winch motor 2 is driven at an increased speed.

Furthermore, when only the second restrictor switching valve 6 is switched to the ``ro'' or ``ni'' position in order to hoist or lower a load using the auxiliary hoisting drum, approximately the entire amount of pressure oil discharged from the first hydraulic pump 1 is The surplus flow is supplied to the oil passage 21 from the surplus flow outlet 4b of the first flow control valve 4, and a part of the surplus flow is controlled by the pilot pressure of the oil passages 23 and 25.
The regulated flow rate outlet 7a of the flow rate control valve 7 is supplied to the second throttle switching valve 6 to drive the second winch motor 5, and the first and second check valves 10 and 11 are connected to oil passages 17 and 21, respectively. It is clear that this prevents the pump discharge oil from flowing back into the unload circuit 9. In this case, the switching valve 12 is switched to the upper position in the diagram by the pilot pressure in the oil passages 25, 25b, and the first check valve 10 is blocked by the pilot pressure in the oil passages 25, 25a, but there is no problem. .

When the second throttle switching valve 6 is further switched to the C or H position from this state, the unload circuit 9 is blocked by the throttle switching valve, and the discharge hydraulic pressure of the second hydraulic pump 8 acts on the oil passage 27. , the first check valve 10 is closed by the aforementioned pilot pressure, and the switching valve 1 is closed.
2 communicates the pilot oil chamber 11a with the tank, so only the second check valve 11 opens and supplies the pressure oil discharged from the second hydraulic pump 8 to the oil passage 21. That is, the pressure oil discharged from both the hydraulic pumps 1 and 8 is combined and supplied to the second flow rate control valve 7, and the second winch motor 5 is driven at an increased speed.

Also, when lifting and lowering a long object that is suspended almost horizontally by the hook block suspension rope (multiple ropes) on the main hoisting drum side and the hook suspension rope (single rope) on the auxiliary hoisting drum side, at a relatively low speed. Since both winch motors 2 and 5 are driven at the same time at significantly different speeds, when both throttle switching valves 3 and 6 are switched to the ``ro'' or ``ni'' positions, the pilot pressure on the oil passage 25 side prevents the reverse. Valve 1
0 is closed, and the switching valve 12 is switched to the pilot pressure discharge position of the check valve 11, but the unload circuit 9
Since the is not blocked, there is no problem, and the regulated flow rate of the pressure oil supplied from the hydraulic pump 1 to the first flow rate control valve 4 from its outlet 4a is controlled by the throttle switching valve 3, and the flow rate is controlled by the throttle switching valve 3. A portion of the surplus flow from the first winch motor 2 and its outlet 4b is controlled by the second flow control valve 7 and the throttle switching valve 6, and is supplied to the second winch motor 5 on the side of the auxiliary winding drum. Therefore, by adjusting the throttle amount of the throttle V by operating the levers of both the throttle switching valves 3 and 6, a speed difference is created between the winch motors 2 and 5 so that the long object can be raised and lowered in a substantially horizontal state. can be set.

In addition, when driving piles by suspending a vibrating pile driver from the hook block on the main hoisting drum side and suspending the piles from the hook on the auxiliary hoisting drum side, the first restrictor switching valve 3 is set to the C position, or When the winch motors 2 and 5 are driven at higher speed by switching the second throttle switching valve 6 to the RO position, the unload circuit 9 is blocked by the first throttle switching valve, and the oil passage 25 side is The check valve 10 is closed by the pilot pressure of the check valve 11, and the switching valve 12 is switched to the pilot pressure discharge position of the check valve 11. It is opened and supplied directly to the oil passage 21,
Also, the discharge amount of the first hydraulic pump 1 is controlled by the first flow control valve 4.
supplied to In this case, by rapidly switching the first throttle switching valve 3 in order to drive the first winch motor 2 at high speed, substantially the entire discharge amount of the first hydraulic pump 1 is changed from the outlet 4a of the first flow rate control valve 4 to the first flow rate control valve 4. The throttle valve 33 is preferentially supplied to the oil passage 27 even if the surplus flow from the outlet 4b decreases significantly.
Since the hydraulic pressure is supplied to the second flow control valve 7, the check valve 10 and the switching valve 12 can be reliably switched as described above, and the second winch motor 5 can be controlled by the valves 7 and 6 and driven at low speed. .

The second flow rate control valve 7
Although we have described the case where the throttle switching valve 6 and the tank T are connected in parallel, the second throttle switching valve and the return to the tank are connected directly to the oil passage 21, similar to the embodiment described in the above-mentioned Japanese Patent Application Laid-Open No. 57-203693. A second flow control valve that controls the flow rate is connected in parallel, and the second flow control valve controls the amount of oil returned to the tank so as to maintain a constant pressure difference before and after the second throttle switching valve. You can also do this. Further, the first and second check valves 10 and 11 are connected to external pilot oil passages 36 and 37, respectively, as shown in FIG.
The second check valve 11 serves as a switching valve that opens when the discharge hydraulic pressure of the second hydraulic pump acts on the second hydraulic pump through the oil passage 27.
A throttle valve 33 may be incorporated therein.

According to the present invention, the two winch motors can be driven independently at arbitrary speeds by the first hydraulic pump, or both winch motors can be simultaneously driven at different speeds to perform the work of lifting a long object together. If possible, it is possible not only to drive each winch motor independently at high speed by the first and second hydraulic pumps, but also to drive one winch motor at high speed by the first hydraulic pump, and drive the other winch motor at high speed. the second
It also has the effect of being able to drive piles with a vibrating pile driver by driving it at low speed with a hydraulic pump.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention, and FIG. 2 is a circuit diagram of main parts of another embodiment. 4a...regulated flow rate outlet, 4b...excess flow rate outlet, 7a...regulated flow rate outlet, 7b...excess flow rate outlet, 10a, 11a...pilot oil chamber, 16...
...Engine, 30...Second check valve blockage oil passage, 3
4,35...Counter balance valve.

Claims (1)

[Claims] 1. A first flow rate between the first hydraulic pump 1 and the first throttle switching valve 3 for controlling the first winch motor 2 to maintain a constant pressure difference before and after the first throttle switching valve. The control valve 4 is connected to the surplus flow outlet of the first flow rate control valve, and a second throttle switching valve 6 and a second flow rate control valve 7 for controlling the second winch motor 5 are connected before and after the second throttle switching valve. an unload circuit connected to the first and second throttle switching valves so as to maintain a constant pressure difference, and connected to the second hydraulic pump 8 by displacement of the spool after the throttles are substantially fully opened; In a control device for a double-barrel winch, each of which is provided with a valve mechanism for blocking a first flow rate control valve 9, a first non-return check is provided between the second hydraulic pump 8 and the inlet of the first flow rate control valve 4, which is closed by the working hydraulic pressure of the second winch motor 5. The valve 10 is connected between the second hydraulic pump and the inlet of the second flow control valve 7, and a second check valve 11 is connected between the second hydraulic pump and the inlet of the second flow control valve 7, and the second check valve 11 is closed by the discharge oil pressure of the second hydraulic pump. A control device for a double-barrel winch, characterized in that a switching valve 12 that is switched by hydraulic pressure and connects a pilot oil chamber of a second check valve 11 to a tank is inserted into the second check valve closed oil path. . 2. The control device for a double-barrel winch according to claim 1, wherein the first winch motor 2 is used to drive the main winding drum, and the second winch motor 5 is used to drive the auxiliary winding drum.