JPS5930279Y2 - Double counterbalance valve for winch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double counterbalance valve suitable for both hoisting and lowering operations of a winch.

Conventionally, as shown in the diagram in FIG. 1, this type of valve has pressure oil supply and discharge passages d and e that communicate with a tank b and a hydraulic pump C, respectively, in a valve housing a, and both passages d and e are connected to each other. is connected to a hydraulic motor j driving a winch drum i via a slidable spool h equipped with a check valve f2g, and the spool h is held in a neutral position by springs provided in chambers at both ends of the spool h. It is known that the chambers at both ends of the chambers are connected to the flow paths d and e through check valves m>n and throttles o and p parallel to the check valves m>n, and in this case, the pressure oil supply and discharge flow paths The switching valves interposed in d and e form their neutral positions in such a way that some ports are open, and when the switching valves are placed in the neutral position, the sprue h of the counterbalance valve automatically returns to the neutral position. Generally, the pressure oil supply/discharge channel d is connected to the tank b so that it can be returned for the next operation.

When the winch is hoisted, the spool h is pressed by the pressure oil in the channel e flowing into one chamber through the check valve n, and the pressure oil in the other chamber is throttled through the counterbalance valve p. When performing a counterbalance action, the spool h throttles the pressure oil in the chamber at the opposite end by the elastic force of the spring k or l to reach 0 or p. The spool h moves in the opposite direction to the direction during winding due to the pressure in the flow path d and the discharge through the throttle 0, and opens the valve when unwinding. In this case, even if the opening area of the aperture p can be increased to improve the mobility of the spool h during winding, that is, the responsiveness of the spool h during winding, the responsiveness of the spool h during counterbalance operation and the spool during lowering may be improved. It is not possible to simultaneously improve the stability of h.

That is, the responsiveness of the spool h during counterbalance operation can be improved by increasing the area of the orifice 0, but on the other hand, the fluid circulation through the orifice 0 becomes too good, so the spool h moves rapidly during lowering. The 00 area of the throttle cannot be increased beyond a certain level because there is a risk that the load will suddenly drop.

If the throttle 0 cannot be made large, for example, even if the switching valve is returned to the neutral position to stop the hoisting operation while hoisting a light load at high speed, the spool h will not be able to quickly return to the neutral position, and the hydraulic pressure during the hoisting operation will be reduced. The motor j overruns due to the delay in stopping, and since the supply of pressure oil from the hydraulic pump C is cut off at this time, cavitation occurs in the flow path on the inflow side of the hydraulic motor j, which is undesirable.

The purpose of the present invention is to provide a counterbalance valve that can be closed quickly in order to reduce the overrun of the hydraulic motor. A slidable spool 6 connects the husband and wife of the channels 2 and 3.
is connected to the two hydraulic motor passages 7, 8 to the winch via a reverse spool 6 which allows fluid to flow from the pressure oil supply/discharge passages 2, 3 into the hydraulic motor passage 1.8. Stop valves 4 and 5 are provided, and the spool 6 is held in a neutral position by springs 11 and 12 provided in chambers 9 and 10 at both ends thereof, respectively.
are individually connected to one of the pressure oil supply and discharge channels 2 and 3 via the respective flow channels 13 and 10, and the spool 6 is moved to the winding position by the pressure of the pressure oil supply and discharge channels 2 and 3. In the device that is slidable to the lowered position, the pressure of the pressure oil supply and discharge passage 2 is applied to the passage 13 connecting one of the pressure oil supply and discharge passages 2 and one of the chambers 9. The check valve 15 that opens is provided, and a throttle 16 is provided in parallel with the check valve 15.
5 and aperture 16, a relatively large diameter through hole 17 is provided which is open when the spool 6 is in the neutral position and the winding position, but is closed when it is in the winding down position.

FIG. 2 shows an example of the valve of the present invention, in which the pressure oil supply and discharge passages 2 and 3 are connected to a tank 19 and a hydraulic pump 20 through a switching valve 18 in a neutral position with some ports open. By switching the switching valve 18, the hydraulic motor 23 connected to the drum 22 of the winch 21 is rotated in the forward and reverse directions or stopped.

24.25 are communication holes 26, 2 formed in the spool 6.
7 and the check valve 4.5 provided in the spool 6, the pressure fluid from the hydraulic pump 20 flowing into either one of the pressure oil supply and discharge channels 2 and 3 is connected to the connecting flow. Road 24,2
5 and one of the check valves 4 and 5, the hydraulic motor flow path 7,
It flows into one side of 8.

The through hole 17 is formed by branching from the flow path 13 provided with the check valve 15, and the opening of the through hole 17 to the chamber 9 is formed when the spool 6 is in the neutral position, as shown clearly in FIG. At some point, a part of the spool 6 is closed, for example by a step 28, and the remaining part opens into the chamber 9.

To explain its operation, when the switching valve 18 is operated to the position 18a, the discharge pressure of the hydraulic pump 20 acts on the pressure oil supply/discharge passage 2, and further flows into the chamber 9 via the passage 13 and its check valve 15. At the same time, the chamber 10 on the opposite side is connected to the tank 19 via the flow path 14 and the pressure oil supply/drainage flow path 3, so the spool 6 is slid to the right in the drawing against the spring 12, and the hydraulic pressure is From the motor flow path 8 to the circulation hole 27 of the spool 6 and the pressure oil supply/discharge flow path 3
Since the return flow path of the tank 19 is formed through the return flow path of the tank 19, the pressure fluid from the pump 20 drives the hydraulic motor 23 of the winch 21 to hoist through the check valve 4 of the spool 6, and then flows through the return flow path. and return to tank 19.

If the switching valve 18 is returned to the neutral position 18b in this state, the spring 1
The spool 6 is pressed by the elastic force of the spool 6, and the other chamber 9 is supplied with relatively low-pressure oil through the through hole 17, which is completely open due to the movement of the spool 6 to the right. Since it communicates with the discharge passage 2, the fluid in the chamber 9 is quickly discharged to the passage 2, and thus the spool 6 quickly returns to the neutral position and is connected to the pressure oil supply and discharge passage 3 and the hydraulic motor passage 8. This can prevent the hydraulic motor 23 from overrunning.

Further, when the switching valve 18 is switched to the position 18c, the spool 6 is initially connected to the pressure of the pressure oil supply/discharge passage 3 acting on the chamber 10,
The chamber 9 on the other side communicates with the pressure oil supply/discharge channel 2 through the partially opened through hole 17 and the throttle 16, so that it moves relatively quickly to the left in the drawing, and the through hole 17 connects to the spool 6. After being closed by the stepped portion 28, fluid flows into the hydraulic motor 23 to lower the winch 21, but at this time, the chamber 9 communicates with the flow path 2 only through the throttle 16, so that the chamber 9 is closed. The fluid becomes difficult to be discharged and acts as a damper for the spool 6, thereby stabilizing the operation of the spool 6 during lowering, which is likely to become unstable, and allowing the load to be lowered smoothly.

During this lowering, when the hydraulic motor 23 runs by itself and the pressure in the pressure oil supply/discharge channel 3 and the hydraulic motor channel 8 decreases, the pressure in the chamber 10 connected via the channel 14 also decreases, so the spool 6
is pushed by the spring 11 of the chamber 9 and moves to the right in the drawing to narrow the through hole 26, thereby performing a counterbalance operation to prevent the hydraulic motor 23 from running on its own.

In this way, according to the present invention, check valves 1 are installed in parallel with each other in the flow path 13 connecting one pressure oil supply and discharge flow path 2 and one chamber 9.
5. A relatively large diameter through hole 11 is provided which is open when the throttle 16 and the spool 6 are in the neutral position and the winding position, but is closed when the winding position is lowered.

When the winch is stopped from hoisting, the spool 6 quickly returns to the neutral position, which prevents overrun of the hydraulic motor 23 and the associated cavitation. Also, when the winch is lowered, the through hole 17 Since it is closed, the stability of the spool 60 is not impaired.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a conventional double counterbalance valve.
FIG. 2 is a cutaway side view of an embodiment of the double counterbalance valve of the present invention, and FIG. 3 is an enlarged view of a portion thereof. 1... Valve housing, 2, 3... Pressure oil supply/drainage channel, 4, 5...
- Check valve, 6... Spool, 7, 8... Hydraulic motor flow path, 9.10... Chamber, 11, 12... Spring, 13
, 14... Channel, 15... Check valve, 16... Throttle, 17... Through hole.

Claims (1)

[Scope of utility model registration request] The two pressure oil supply/discharge passages 2 and 3 formed in the valve housing 1 are connected to the two hydraulic motor passages 7 and 8 to the winch via a slidable spool 6, respectively. The spool 6 is provided with a check valve 4.5 for allowing fluid to flow from the pressure oil supply and discharge passages 2 and 3 into the hydraulic motor passages 7 and 8. The chambers 9 and 10 are held in a neutral position by springs 11 and 12 provided respectively, and each chamber 9 and 10 is individually connected to one of the pressure oil supply and discharge channels 2 and 3 via the respective flow channels 13 and 10. In a device in which the spool 6 is slid between a winding position and a winding down position by the pressure of the pressure oil supply and discharge passages 2 and 3, one pressure oil supply and discharge passage 2 and one chamber 9 are connected to each other. The connecting flow path 13 is provided with the reverse valve 15 that opens by the pressure of the one pressure oil supply/discharge flow path 2, and a throttle 16 is provided in parallel with the check valve 15. A double counterbalance valve for a winch is provided in parallel with a comparatively large diameter through hole 17 which is open when the spool 6 is at the neutral position and the winding position, but is closed when the winding position is lowered.