JP2003182982A - Control method and device for hydraulically driven winch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of cavitation and a load swing at deceleration during high speed lowering in a small motor capacity state. <P>SOLUTION: A sub route 18 with a pressure oil makeup valve 19 is connected to a lowering side line 5 of a hydraulic motor 3. At the high speed lowering operation, the sub route 18 supplies pressure oil to the motor lowering side line 5 along with a main route 17 passing a control valve 6. Even when a meter-in orifice of the control valve 6 is restricted at the deceleration during the high speed lowering, the sub route 18 supplies makeup pressure oil to maintain a constant motor inlet pressure or higher. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a hydraulic drive winch in which a variable displacement hydraulic motor for driving a winch drum is set to a small displacement so as to rotate the winch drum at a high speed. is there.

[0002]

2. Description of the Related Art As described above, a system in which a hydraulic motor is rotated at a high speed with a small capacity to obtain a free fall function is disclosed in Japanese Unexamined Patent Publication No. HEI-1.
It is publicly known as shown in 0-330088, JP-A-11-79679 and the like.

In this known technique, a hydraulic pilot switching type control valve is unwinded by a remote control valve, and at the same time, the remote control pressure is used to operate a motor capacity control cylinder to switch the motor capacity to a small capacity. Is taking.

Further, at this time, the pump discharge pressure is set to a low pressure in order to prevent the rope from being loosened or irregularly wound due to the motor rotating speed becoming too high and to suppress wasteful use of pump horsepower. Is also proposed.

[0005]

However, according to the known technique, during deceleration from a high-speed unwinding state, the influence of the inertia of the suspended load is affected as compared with (a) when the motor capacity is large (low-speed unwinding). Since the deceleration force obtained by the meter-out throttle of the control valve is large, the pumping action of the motor is large, and (b) the meter-in opening is throttled to reduce the supply flow rate to the motor winding side pipeline. To decrease the motor inlet pressure.

As a result, cavitation occurs, the counterbalance valve for braking causes hunting or sudden braking, and the suspended load is greatly shaken, so that the winch cannot be smoothly decelerated or stopped. It was

Therefore, the present invention provides a control device for a hydraulic drive winch capable of preventing the occurrence of cavitation and load sway during deceleration during high-speed winding in a motor small capacity state.

[0008]

According to the present invention, there is provided a winch drum, a variable displacement hydraulic motor for driving the winch drum, a hydraulic pump as a hydraulic source of the hydraulic motor, and the hydraulic motor. A control valve that controls the supply and discharge of pressure oil, a relief valve that sets the discharge pressure of the hydraulic pump, a motor capacity control means that controls the capacity of the hydraulic motor, and a small motor capacity command to this motor capacity control means. The hydraulic motor is set to a small capacity by the action of the motor capacity control means based on a command from the command means, and the control valve is operated to the lower side,
In a hydraulic drive winch configured such that the winch drum rotates at a high speed to perform a high speed lowering operation, a sub route having a pressure oil supply valve is connected to a lower side pipeline of the hydraulic motor. During the high-speed unwinding operation, the pressure oil replenishing valve is opened to supply the pressure oil to the unwinding side pipeline through the sub route other than the main route through the control valve. .

According to a second aspect of the present invention, in the configuration of the first aspect, the pressure oil from one hydraulic pump is divided into a main route and a sub route to be supplied.

According to a third aspect of the present invention, in the structure of the first or second aspect, pump pressure control means for controlling the set pressure of the relief valve is provided, and when the winch drum rotates at high speed, the pump pressure control means controls the pressure. The pump discharge pressure is set to a low pressure.

According to a fourth aspect of the present invention, in the configuration of the third aspect, the pump pressure control means starts switching the pump discharge pressure to a high pressure after the pressure oil supply valve starts to close at the time of deceleration of the high-speed lowering operation. It is configured to do.

According to the above construction, during the high-speed unwinding operation, in addition to the main route through the control valve, pressure oil is supplied to the motor lower-side pipe line by the sub-route equipped with the pressure oil replenishment valve, so Even if the meter-in opening of the control valve is throttled during deceleration, the pressure oil is replenished through the sub route. Therefore, since the motor inlet pressure is maintained above a certain level, it is possible to prevent the occurrence of cavitation, the hunting of the counterbalance valve, and the sudden braking operation, and to smoothly perform the deceleration / stop control.

According to the above construction, when the control valve is operated to the upper side of the winding while the motor capacity is set to a small capacity, the hydraulic motor rotates at a high speed to perform a high speed winding operation.

In this case, according to the second aspect of the invention, since the pressure oil from the same pump is supplied separately to the main route and the sub route, the total motor flow rate during high speed winding and the motor flow rate during high speed winding are different. Will be the same. Therefore, since the winding speed at the high speed and the winding speed at the high speed are the same, the operation is comfortable and the operability is good.

According to the third aspect of the present invention, the pump discharge pressure is set to a low pressure during high-speed unwinding, so that the motor rotation speed does not become too high, and the rope does not loosen or is wound irregularly. It is possible to perform a close operation, and there is no loss of pump horsepower, which saves energy.

According to the structure of claim 4, during deceleration during high-speed winding, the pump pressure is switched to a high pressure before the pressure oil supply valve starts closing, and this high pressure acts on the motor inlet side via the sub route. As a result, the oil in the pipeline is compressed, and there is no possibility that the motor will momentarily move to the lower side.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings.

First Embodiment (Refer to FIGS. 1 and 2) In FIG. 1, reference numeral 1 is a winch drum, and a rotary shaft 2 of the winch drum 1 is connected to a variable displacement winch hydraulic motor 3 by the motor 3. The winch drum 1 is rotationally driven.

Both the winding-side and winding-side pipelines 4 and 5 constituting the drive circuit of the hydraulic motor 3 are of a hydraulic pilot switching type having three positions of neutral, winding and winding. It is connected to a hydraulic pump 7 via a control valve 6, and the control valve 6 controls supply / discharge of pressure oil to / from the motor 3 (driving, stopping, rotating direction and speed of the motor 3).

Reference numeral 8 is a remote control valve for operating the control valve 6 on the winding side or the winding side.
The remote control pressure (pilot pressure) Pi according to the operation amount of the winding side, the winding side of the control valve 6 by the winding side pilot lines 9, 10
a, 6b. Reference numeral 11 is a counter balance valve that generates a hydraulic braking force when it is unwound.

Motor capacity control means for controlling the capacity of the hydraulic motor 3 will be described.

Reference numeral 12 denotes a motor capacity adjusting cylinder (capacity adjusting cylinder) for changing the motor capacity by changing the tilt angle of the hydraulic motor 3. The motor 3 has a large capacity when the capacity adjusting cylinder 12 is contracted. Is set to
It is set to a small capacity in the expanded state.

The extension side oil chamber 1 of the capacity adjusting cylinder 12
An electromagnetic switching type cylinder control valve 13 is connected to 2a.

The cylinder control valve 13 has a large capacity position a and a small capacity position b. At the large capacity position a, the cylinder expansion side oil chamber 12a communicates with the tank T and the capacity adjusting cylinder 12 contracts. (The motor 3 is set to a large capacity).

Electromagnetic operation portion 13a of the cylinder control valve 13
Is a power source 1 via a changeover switch 14 as command means.
5, the cylinder control valve 13 is switched to the small capacity position B when the changeover switch 14 is turned on.

In this state, the oil in the winding side pipe line 4 or the winding side pipe line 5 is introduced into the cylinder extension side oil chamber 12a via the high pressure selection valve 16, whereby the cylinder 12 is extended and the motor 3 is operated. Is set to a small capacity.

On the other hand, between the hydraulic pump 7 and the lower pipe line 5, a sub route 18 for supplying pressure oil to the lower pipe line 5 in parallel with the main route 17 passing through the control valve 6.
The sub-route 18 is provided with a hydraulic pilot type pressure oil replenishment valve 19 that switches between a closed position a and an open position b.

Pilot port 1 of this pressure oil supply valve 19
9a is connected to the unwinding side pilot line 10 via an electromagnetic switching type high-speed unwinding valve 20, and when the changeover switch 14 is turned on, the high-speed unwinding valve 20 opens from the closed position a shown in the figure. The lower pilot pressure Pi is supplied to the pilot port 19a of the pressure oil supply valve 19 by switching to position B.

As a result, the pressure oil replenishing valve 19 is switched to the open position B, and the oil discharged from the hydraulic pump 7 is supplied to the unwinding side pipeline 5 via the sub route 18.

That is, during high-speed unwinding, the oil discharged from the hydraulic pump 7 is divided into both the main and sub routes 17 and 18 and supplied in parallel to the unwinding side pipeline 5.

Next, a structure for setting the pump pressure to a low pressure during high speed winding will be described.

Reference numeral 21 is a variable relief valve for setting the pump pressure. The pilot side pressure port of this relief valve 21 is
It is connected to the tank T via a hydraulic pilot type pump pressure switching valve 22 that switches between a closed position a and an open position b, and a pump pressure setting valve 23.

With this structure, when the high-speed unwinding valve 20 is set to the open position B and the remote control valve 8 is unwinding operation, the unwinding side pilot pressure Pi changes the pump pressure switching valve 2
2 is supplied to the pilot port 22a of the second switching valve 22
Is switched to the open position B, and the set pressure (pump pressure) of the relief valve 21 is set to a value determined by the set pressure of the pump pressure setting valve 23.

The pump pressure determined by the pump pressure setting valve 23 is set to such a value that the relation of pump pressure and suspension load amount> rotational resistance of the winch drum 1 is established.

In the above structure, the changeover switch 14 is turned off and the high-speed lowering valve 20 is set to the closed position B during normal winding and winding.

In this state, the motor capacity is set to a large capacity and the pump pressure is set to a high pressure, and the hydraulic motor 3 operates the operation amount of the remote control valve 8 (stroke of the control valve 6).
A normal hoisting / lowering operation is performed by rotating at a speed according to.

Next, when performing high-speed unwinding operation, the changeover switch 14 is turned on to switch the high-speed unwinding valve 20 to the open position B.

When the remote control valve 8 is unwound in this state, the motor capacity is set to a small capacity and the pump pressure is set to a low pressure. Therefore, the hydraulic motor 3 rotates at a high speed at a low speed and a high speed lower speed operation is performed. Is done.

At this time, the meter-in and meter-out openings of the control valve 6 change according to the amount of the lowering operation of the remote control valve 8, and the motor flow rate changes, so the lowering speed is adjusted by the remote control valve 8, or It can be stopped.

Further, since the pump pressure is set to a low pressure during the high-speed unwinding, the motor rotation speed does not become too high, and the unwinding operation close to the free fall can be performed without loosening or irregular winding of the rope. Thus, there is no waste (horsepower loss) of operating the pump 7 at high pressure, thus saving energy.

However, with this alone, the influence of the inertia of the suspended load is large during deceleration during high-speed unwinding as described above, as compared to (a) when the motor capacity is large (during low-speed unwinding), and the control valve 6 Since the deceleration force obtained by the meter-out throttle is small, the pumping action of the motor 3 becomes large, and (b) the meter-in opening of the control valve 6 is throttled so that the flow rate supplied to the lower side conduit 5 is reduced. To the inlet pressure of the motor 3 (rolling side pipeline 5
Therefore, there is a problem that cavitation occurs, and as a result, the counterbalance valve 11 causes hunting or sudden braking, and the suspended load is greatly shaken.

On the other hand, in this device, the pressure oil replenishing valve 19 is opened during high-speed unwinding, and pump discharge oil is supplied to the unwinding side pipeline 5 by the sub-route 18 in addition to the main route 17, thus decelerating. Even if the meter-in opening of the control valve 6 is sometimes throttled, the pressure oil is replenished by the sub route 18 so that the motor inlet pressure is maintained at a certain level or higher.

As a result, the occurrence of cavitation, the hunting of the counterbalance valve 11 and the sudden braking operation are prevented, and the deceleration / stop control is smoothly performed.

By the way, the pilot oil pressure characteristic is set so that the pressure oil supply valve 19 and the pump pressure switching valve 22 are switched and operated at the timing shown in FIG.

That is, the pressure oil supply valve 19 is switched to the open position b at the point C where the meter-in opening of the control valve 6 starts to open, and the operation is completed.

The pump pressure switching valve 22 switches to the open position B before the meter-in opening of the control valve 6.

The pump pressure switching valve 22 is the pressure oil supply valve 19
It switches to the open position B before.

The above setting considers that the pressure oil replenishing valve 19 and the pump pressure switching valve 22 operate with a certain gradient as a characteristic of the hydraulic pilot type switching valve having the return springs 19b and 22b. This is to prevent (when the meter-in opening is open, make sure that both valves 19 and 22 are open).

On the other hand, with the above settings, the hydraulic motor 3
The pump pressure can be set to a low pressure prior to the supply of pressure oil to the pump, and the high-speed unwinding operation can be reliably started at a low pressure.

Further, according to the above setting, the pump pressure is switched to the high pressure after the replenishment of the pressure oil in the sub route 18 having the pressure oil replenishment valve 19 is stopped at the time of deceleration at the high speed winding (always during the pressure oil replenishment. Since the pressure is kept low, the high voltage is transmitted to the motor inlet side as if the order was reversed, and the motor 3
There is no danger of the momentarily moving to the unwinding side.

However, the above setting is applied to the pressure oil supply valve 19
It becomes unnecessary when using an on-off valve with no operation delay.

Further, if it is compensated by other means that the low pressure setting by the pump pressure switching valve 22 is surely started at the opening of the meter-in opening, the setting may be removed.

Further, the setting of is also unnecessary in an environment where the action of the motor 3 momentarily moving to the lower side does not pose a problem.

When the remote control valve 8 is hoisted while the changeover switch 14 is on, the hydraulic motor 3 is hoisted and rotated at a high speed with a small capacity to perform a high speed hoisting operation.

At this time, since the sub route 18 is closed, all the oil from the hydraulic pump 7 is supplied to the motor 3 via the main route 17.

In this case, the motor flow rate (motor speed) during high-speed winding and during high-speed winding is the same if the operation amount of the remote control valve 8 is the same. There will be no discomfort and the operability will be good.

Other Embodiments (1) As a second embodiment, as shown in FIG. 3, electromagnetic switching valves are used for the pressure oil supply valve 19 and the pump pressure switching valve 22, while the unwinding side pilot pressure Pi is set to the pressure. This is detected by the sensor 24 and taken into the controller 25, and the controller 2
The valves 19 and 22 may be switched from the closed position (a) to the open position (b) by a signal from 5. 19c,
Reference numeral 22c is an electromagnetic operation portion of both valves 19 and 22.

According to this structure, the high-speed lowering valve 20 of the first embodiment is unnecessary.

Further, in this second embodiment, in order to have the same characteristic as that of FIG. 2 in the first embodiment, as shown in FIG. 4, both valves 19, 22 with respect to the lower pilot pressure Pi. The operation timing of may be shifted.

In this case, the characteristics of FIG. 4 can be easily set by the controller 25 even under the condition that the range from the meter-in opening point (point C in FIG. 2) of the control valve 6 to neutral is physically narrow.

(2) As a modified example (third embodiment) of the second embodiment, as shown in FIG. 5, the pump pressure switching valve 22 and the pump pressure setting valve 23 in the second and second embodiments are combined into a single electromagnetic proportional valve. The pump pressure setting valve 26 of the relief valve type may be replaced and the controller 25 may control the pump pressure setting valve 26 to set the pump pressure to a low pressure during high-speed lowering.

With this configuration, the number of valves in the pump pressure control system can be reduced as compared with the second embodiment.

Also in the third embodiment, the operation timing of the pump pressure setting valve 26 may be shifted with respect to the lower pilot pressure Pi as in the second embodiment.

Further, as shown in FIG. 6, a command value given to the pump pressure setting valve 26 from the controller 25 is set so that the set pressure of the relief valve 21 at the time of accelerating the lowering is higher than the set pressure at the time of decelerating the lowering. You may set it. In this way, the unwinding acceleration force can be changed freely and easily.

(3) In each of the above embodiments, the main and sub routes 17, 18 have the same hydraulic source (hydraulic pump 7), but these hydraulic sources may be different.

(4) As the motor capacity control means, an electric motor and an electric motor control circuit for controlling the electric motor may be used instead of the capacity adjusting cylinder 12 and the cylinder control valve 13 used in the above embodiment.

(5) As the control valve 6, an electromagnetic pilot type switching valve operated by an electric signal or a manual type switching valve may be used instead of the hydraulic pilot type switching valve described in each of the above embodiments.

When a manual switching valve is used, the movement of the control valve may be detected and the pressure oil supply valve 19 and the pump pressure control means may be controlled based on the detection result.

[0069]

As described above, according to the present invention, at the time of high-speed unwinding operation, the pressure oil is supplied to the motor lowering side pipe line by the sub route provided with the pressure oil replenishing valve in addition to the main route through the control valve. Even if the meter-in opening of the control valve is throttled during deceleration during high-speed winding, pressure oil is replenished through the sub route to keep the motor inlet pressure above a certain level. Prevents valve hunting and sudden braking,
Deceleration / stop control can be performed smoothly.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a pilot pressure of a remote control valve and a meter-in opening of a control valve, a pressure oil supply valve, and an opening of a pump pressure switching valve according to the first embodiment.

FIG. 3 is a circuit configuration diagram of a second embodiment of the present invention.

FIG. 4 is a diagram showing an operating state of a pressure oil supply valve and a pump pressure switching valve with respect to a pilot pressure of a remote control valve according to a second embodiment.

FIG. 5 is a circuit configuration diagram of a third embodiment of the present invention.

FIG. 6 is a diagram showing an operating state of a pressure oil supply valve and a pump pressure switching valve with respect to a pilot pressure of a remote control valve according to a third embodiment.

[Explanation of symbols]

1 winch drum 3 hydraulic motor 4 winding upper pipeline 5 winding lower side pipeline 6 control valve 7 hydraulic pump 8 remote control valve 12 Capacity adjustment cylinder constituting motor capacity control means 13 Cylinder control valve 14 Changeover switch that constitutes command means 20 Same high-speed unwinding valve 17 Main route 18 subroute 19 Pressure oil supply valve 21 relief valve 22 Pump pressure switching valve constituting pump pressure control means 23 Same pump pressure setting valve 25 Controller constituting command means 26 Pump pressure setting valve

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Claims (4)

[Claims] 1. A winch drum, a variable displacement hydraulic motor for driving the winch drum, a hydraulic pump as a hydraulic source of the hydraulic motor, and a control valve for controlling the supply and discharge of pressure oil to the hydraulic motor. , A relief valve for setting the discharge pressure of the hydraulic pump, a motor capacity control means for controlling the capacity of the hydraulic motor, and a command means for commanding a small motor capacity to the motor capacity control means. When the hydraulic motor is set to a small capacity by the action of the motor capacity control means based on the command and the control valve is operated to the lower side, the winch drum rotates at a high speed and rotates at a high speed. In the hydraulic drive winch configured to perform the unwinding operation, in the unwinding side pipeline of the hydraulic motor,
A sub-route equipped with a pressure oil supply valve is connected, and during the high-speed unwinding operation, the pressure oil supply valve is opened, and the sub-route separates from the main route that passes through the control valve to the unwinding side pipeline. A control device for a hydraulically-operated winch, characterized in that it is configured to supply. 2. The control device for the hydraulically-operated winch according to claim 1, wherein the pressure oil from one hydraulic pump is divided into a main route and a sub route to be supplied. 3. A pump pressure control means for controlling the set pressure of the relief valve is provided, and the pump discharge pressure is set to a low pressure by the pump pressure control means when the winch drum rotates at a high speed. Claim 1 characterized by the above.
Alternatively, the control device for the hydraulically-operated winch according to Item 2. 4. The pump pressure control means is configured to start switching the pump discharge pressure to a high pressure after the pressure oil supply valve starts to close during deceleration of the high-speed unwinding operation. The control device for the hydraulically-operated winch according to Item 3.