JP2000226189A - Hydraulic circuit for driving winch drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent overload on hydraulic motors, to increase no burden on an operator, and to prevent imbalance on a load acted on a wire rope and on falling a bucket in lowering the bucket. SOLUTION: In this hydraulic circuit, hydraulic motor 2a, 2b sides are connected to each other through an equalizing pipe line 23 having a directional control valve 24 at its midway part rather than a part having the counter balance valves 15a, 15b of main pipe lines 7a, 7b for returning liquids from the hydraulic motors 2a, 2b to directional control valves 6a, 6b in lowering a bucket 5. Pressure switches 26a, 26b are provided to the directional control valve 24 so that the main pipe line 7a may be communicated with the main pipe line 7b in lowering the bucket 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane for lifting and lowering a single suspended body with a plurality of winches using a variable displacement hydraulic motor. In addition, the present invention relates to a winch drum driving hydraulic circuit which can tune and drive respective variable displacement hydraulic motors so that the loads acting on the respective winches become substantially equal.

[0002]

2. Description of the Related Art For example, in a digging bucket for digging a continuous wall, one digging bucket is wound up and down by a plurality of winches using a variable displacement hydraulic motor. FIG. 2 shows a conventional example of a winch drum drive hydraulic circuit used for a winch.

[0003] In the following description, the winch drum drive hydraulic circuit includes two winch drum drive hydraulic systems,
Devices having the same reference numerals with a and b all have the same capacity and the same capacity.

In FIG. 2, reference numerals 1a and 1b denote two winch drums. The winch drums 1a and 1b can be independently driven by hydraulic motors 2a and 2b such as variable displacement hydraulic motors. ing.

Wire ropes 3a and 3b are wound around the winch drums 1a and 1b, respectively, so that the wire ropes 3a and 3b can be wound or unwound. The wire ropes 3a and 3b are moved downward from the end of the crane boom 4. The bucket 5 which extends and excavates the continuous wall can be wound up and down.

Switching valves 6a, 6b and hydraulic motors 2a, 2b
Are connected by main pipelines 7a, 7b and 8a, 8b,
The liquid from the hydraulic pressure supply sources 9a, 9b having a hydraulic pump or the like can be supplied from the switching valves 6a, 6b to the hydraulic motors 2a, 2b. 10a and 10b are tanks, 11
a and 11b are relief valves.

In the middle of the main pipelines 7a, 8a, 7b, 8b, unload valves 12a, 12b and unload valves 12 are provided.
check valves 13a, 13 arranged in parallel with a, 12b
b, counter balance valves 15a and 15b provided with relief valves 14a and 14b, respectively.

The unload valves 12a, 12b of the counter balance valves 15a, 15b and the flow path 1 on the main pipelines 8a, 8b side
7a and 17b are connected by pilot lines 16a and 16b, and the pressure of the liquid flowing in the main lines 8a and 8b is increased from the pilot lines 16a and 16b to the unload valves 12a and 16b.
12b.

Counter balance valve 1 for main lines 7a, 7b
The constant horsepower control valves 18a and 18b are connected to the hydraulic motors 2a and 2b with respect to the connection positions 5a and 15b.
The constant horsepower control valves 18a, 18b are connected to the hydraulic motors 2 of the main pipelines 7a, 7b in the counter balance valves 15a, 15b.
A valve for automatically adjusting the displacement of the hydraulic motors 2a, 2b so as to act when the pressures on the sides a, 2b reach the set pressure and to maintain the set pressure. The main lines 7a, 7b
Regulating valves 19a, 19b switched by the pressure of the liquid from
And actuators 20a and 20b which are operated by the pressure of the liquid from the regulating valves 19a and 19b and the main lines 7a and 7b or the pressure of the liquid from the main lines 7a and 7b.

The liquid supplied from the hydraulic pressure source 28 for switching the switching valves 6a and 6b is switched by the remote control valves 21a and 21b to be switched.
On the hoisting side or the lowering side, so that the switching valves 6a and 6b can be switched. In the figure, 22a, 2
2b is a lever for operating the remote control valves 21a and 21b, and q1 and q2 are actuators 20a and 2b.
0b.

When the bucket 5 is wound up by synchronizing the rotation speeds of the winch drums 1a and 1b by the above-described winch drum drive hydraulic circuit, the following operation is performed.
That is, when the remote control valves 21a, 21b are operated to the winding side so that the levers 22a, 22b are tilted to the full in the winding direction, the liquid from the hydraulic pressure supply source 28 is supplied from the remote control valves 21a, 21b to the switching valves 6a, 6b.
b, and the switching valves 6a and 6b are switched to the winding side.

For this reason, the liquid from the hydraulic pressure supply sources 9a, 9b is introduced into the hydraulic motors 2a, 2b from the main pipelines 7a, 7b through the switching valves 6a, 6b, and the respective hydraulic motors 2a, 2b
b is rotated in the winding direction. The hydraulic motors 2a, 2b
Is driven from the main pipelines 8a and 8b side by the switching valves 6a and 6b.
6b, and returns to the tanks 10a and 10b.

The rotation speed V of the hydraulic motors 2a, 2b is Q
Is the flow rate of the liquid introduced into the hydraulic motors 2a and 2b, and q is the displacement of the hydraulic motors 2a and 2b, and V = Q /
q, the rotational force T of the hydraulic motors 2a, 2b is p
Is the pressure of the liquid introduced into the hydraulic motors 2a and 2b, T = p · q. That is, the rotation speed V is the speed of the bucket 5 and the rotation force T is the mass of the bucket 5.

The constant horsepower control valves 18a and 18b are arranged so that when a set load pressure is reached, V · T = constant.
The displacement of the hydraulic motors 2a and 2b is automatically adjusted.

When the operating pressure due to the mass of the bucket 5 exceeds the set pressure of the constant horsepower control valves 18a and 18b when the flow rate Q is constant, the constant horsepower control valves 18a and 18b operate so that the hydraulic motors maintain the set pressure. It operates in the direction to increase the displacement capacity q of 2a, 2b.

When the flow rate Q of the liquid introduced into the hydraulic motors 2a and 2b is constant, if the displacement q is small, the rotation speed V of the hydraulic motors 2a and 2b is high and the displacement q is large. If the capacity is large, the rotation speed V of the hydraulic motors 2a and 2b is low.

When winding the bucket 5, the two levers 22a and 22b are simultaneously operated in the same winding direction as in the previous operation. At that time, the timing of the rotation start of the winch drums 1a, 1b is shifted, or the operating winch drums 1a, 1b
In the case where the winding layer 1b changes, the tension is applied to one of the wire ropes 3a and 3b, whereas the two wire ropes 3a and 3b should be equally tensioned. There are cases.

For example, when the tension of the wire rope 3a becomes larger than the tension of the wire rope 3b, the load pressure of the liquid introduced from the main line 7a to the hydraulic motor 2a increases, and this load pressure becomes constant horsepower in FIG. Acts on the control valve 18a. For this reason, when the load pressure becomes higher than the predetermined set pressure of the constant horsepower control valve 18a, the constant horsepower control valve 18a
The control valve 19a is switched so as to maintain the set pressure, and the actuator 20a operates in the q1 direction. As a result, the displacement of the hydraulic motors 2a and 2b is increased, so that the rotation speed of the hydraulic motor 2a is reduced and the winding speed of the wire rope 3a is reduced.

On the other hand, the hydraulic motor 2b on the side with the smaller rope tension winds up the wire rope 3b at a high speed with a small displacement capacity because the load pressure is small, and the wire rope 3b catches up with the speed of the wire rope 3a. Tension increases. That is, the operation is performed such that the load pressures of the hydraulic motors 2a and 2b become equal. As a result, the hydraulic motors 2a, 2
b rotates at the synchronized rotation speed, and the bucket 5 is wound up in a state where the posture is balanced.

When lowering the bucket 5 by synchronizing the rotation speeds of the winch drums 1a and 1b, the following operation is performed.

That is, when the levers 22a and 22b are fully tilted toward the lowering side, the liquid from the hydraulic pressure supply source 31 acts on the lowering sides of the switching valves 6a and 6b, and the switching valves 6a and 6b Switch to lower side.

For this reason, the liquid from the liquid supply sources 9a and 9b is introduced into the hydraulic motors 2a and 2b from the main pipelines 8a and 8b, and rotates the hydraulic motors 2a and 2b in the lowering direction. The liquid that has driven the hydraulic motors 2a and 2b is
tanks 10a, 10b from the unload valves 12a, 12b of the counter balance valves 15a, 15b from the sides a, 7b.
Return to At this time, the unload valve 12 of the main pipelines 7a and 7b
Since the holding pressure is generated closer to the hydraulic motors 2a and 2b than a and 12b in accordance with the pilot pressure of the main pipelines 8a and 8b, the bucket 5 does not run down and descend during the lowering.

When lowering the bucket 5, the two levers 22a and 22b are simultaneously operated in the same lowering direction.
At this time, if the rotation start timings of the winch drums 1a, 1b are shifted or if the winding layers of the winch drums 1a, 1b change during operation, the two wire ropes 3a, 3b should be evenly distributed. Where the tension is to be applied, the tension may act on one of the wire ropes 3a or 3b, resulting in imbalance.

For example, when the tension of the wire rope 3a becomes larger than that of the wire rope 3b, the pressure in the main pipeline 7a from the hydraulic motor 2a to the unload valve 12a of the counter balance valve 15a increases, and the holding pressure increases. When the pressure exceeds the set pressure of the constant horsepower control valve 18a, the constant horsepower control valve 1
The control valve 8a of 8a switches so as to maintain the set pressure, and the actuator 20a operates in the q1 direction. As a result, the displacement of the hydraulic motor 2a is increased, and as a result, the rotation speed of the hydraulic motor 2a is reduced, and the lowering speed of the wire rope 3a is lower than the lowering speed of the wire rope 3b.

[0025]

In the above-described winch drum driving hydraulic circuit, the levers 22 of the remote control valves 21a and 21b are synchronized so that the rotation speeds of the hydraulic motors 2a and 2b are synchronized when the bucket 5 is lowered.
a and 22b must be adjusted, but if such adjustment is not performed, the load imbalance occurs in the hydraulic motors 2a and 2b, and the hydraulic motors 2a and 2b may be overloaded. There is.

When the bucket 5 is lowered, the hydraulic motor 2
In order to synchronize the rotation speeds of the hydraulic motors 2a and 2b, the operator frequently adjusts the inclination of the levers 22a and 22b in the remote control valves 21a and 21b as described above. This has to be done, which places a heavy burden on the operator and causes fatigue.

Furthermore, the load acting on the wire ropes 3a and 3b due to the uneven load when the bucket 5 is lowered causes an unbalance in the attitude of the bucket 5 when the bucket 5 is lowered.

In view of the above-mentioned circumstances, the present invention does not overload the hydraulic motor when the bucket is lowered, does not increase the burden on the operator, increases the load acting on the wire rope and the lowering posture of the bucket. It is an object of the present invention to provide a winch drum drive hydraulic circuit in which unbalance does not occur.

[0029]

According to the present invention, a plurality of winch drum driving hydraulic systems are provided, and each of the winch drum driving hydraulic systems winds and unwinds a wire rope with a suspended body. A liquid pressure motor for driving the winch drum and a liquid supplied to the liquid pressure motor when hoisting the suspension, and discharged from the liquid pressure motor when lowering the suspension. A first main line configured to supply the liquid, and a liquid discharged from the hydraulic motor when the suspension is supplied to the hydraulic motor when the suspension is wound and the suspension is wound. A second main conduit adapted to be fed, and a second main conduit adapted to supply liquid from a hydraulic pressure source to the first or second main conduit.
Or a first switching valve configured to be switched to return the liquid from the first main line to the tank, and when the hanging body is wound up, the liquid from the first switching valve is supplied to the hydraulic motor, A check valve that shuts off the liquid from the hydraulic motor to prevent the liquid from being supplied to the first switching valve when the hanging body is lowered; and a first main line from the hydraulic motor when the hanging body is lowered. And a counter balance valve having an unload valve for generating a holding pressure in accordance with the pilot pressure of the second main line on the hydraulic motor side of the first main line on the liquid returning to the tank via the switching valve; Constant horsepower control for automatically adjusting the displacement of the hydraulic motor so as to operate when the pressure on the hydraulic motor side of the first main line in the counter balance valve reaches a set pressure and maintain the set pressure. Valve and multiple winch drums A hydraulic circuit for driving a winch drum, which is capable of hoisting and lowering a suspended body, wherein the first main lines in each winch drum driving hydraulic system are connected to the counter balance valve of the first main line. A pressure equalizing pipeline connected on the hydraulic motor side of the pressure equalizing section, a second switching valve connected to an intermediate portion of the pressure equalizing pipeline, and a first switching valve in each winch drum driving hydraulic system. Switch means for switching the second switching valve so that the first main lines in each winch drum drive hydraulic system communicate with each other when the liquid is supplied to the hydraulic motor so as to lower the hydraulic pressure. Things.

In the present invention, a remote control valve for switching the first switching valve for hoisting or lowering the suspended body may be provided for each winch drum drive hydraulic system.

Further, in the present invention, when the first switching valve of each winch drum driving hydraulic system is switched to lower the suspension body by a plurality of winch drums, each winch drum driving hydraulic system is used as the switch means. The pressure switch which is turned on by the pressure of the liquid from the remote control valve in the above, supplies power from the power supply to the second switching valve through each system, and switches the second switching valve so that the first main lines communicate with each other. It is good to provide for each winch drum drive hydraulic system.

In the present invention, when the suspension body is lowered, the liquid from the hydraulic pressure supply source is introduced from the first switching valve to the hydraulic motor via the second main line, and the hydraulic motor is driven. Then, the fluid is discharged from the hydraulic motor, passes through the unload valve, returns to the tank via the first switching valve.

When the suspension is wound down in synchronization, the second switching valve is switched so that the first main lines of the different hydraulic systems for driving the winch drum communicate with each other, and the first main line in the first main line is connected. Since the liquid holding pressure is equalized, the displacements of the hydraulic motors are equal, so that the suspensions synchronize and descend at the same speed.

Accordingly, no overload occurs in the hydraulic motor, the burden on the operator does not increase, and no imbalance occurs in the load acting on the wire rope and the falling posture of the bucket. Further, it can be easily and inexpensively provided in an existing device.

[0035]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an embodiment of a winch drum drive hydraulic circuit according to the present invention. The basic structure of the hydraulic circuit is substantially the same as the conventional one shown in FIG. A description will be given of parts different from the drum drive hydraulic circuit. In FIG. 1, the same components as those shown in FIG. 2 are denoted by the same reference numerals.

One end of the pressure equalizing line 23 is connected between the connection portion of the counter balance valve 15a and the connection portion of the constant horsepower control valve 18a of the main line 7a, and the other end of the pressure equalizing line 23 is connected to the main line 7b. Is connected between the connection portion of the counter balance valve 15b and the connection portion of the constant horsepower control valve 18b, and a switching valve 24 is provided in the middle of the pressure equalizing line 23.

The pipes 25a, 25b through which the liquid is sent from the remote control valves 21a, 21b to switch the switching valves 6a, 6b to the lowering side are turned on by the pressure of the liquid in the pipes 25a, 25b. Pressure switch 26
a, 26b are connected and the pressure switches 26a, 2
When the switch 6b is turned on, electricity from the power supply 27 is supplied to the switching valve 24 via the pressure switches 26a and 26b, and the switching valve 24 can be switched so that the main pipelines 7a and 7b communicate with each other. I have. That is, an AND circuit is formed by the pressure switches 26a and 26b and the electric system.

Next, the operation of the embodiment of the present invention will be described.

When the winch drums 1a, 1b are driven by the above-described winch drum drive hydraulic circuit to wind up the bucket 5, the levers 22a, 22b are tilted fully in the hoisting direction and the remote control valves 21a, 2b are tilted.
1b is switched to the winding side. For this reason, the switching valves 6a, 6
b is switched to the winding side.

In this case, the pressure switch 26
Since the pressure of the liquid does not act on a and 26b, the pressure switches 26a and 26b are off as shown in FIG.
The switching valve 24 shuts off the main lines 7a and 7b. Therefore, the operation of the winch drum driving hydraulic circuit when the bucket 5 is wound up in the present embodiment is completely the same as that of the conventional case, and the description is omitted.

When the winch drums 1a, 1b are driven to lower the bucket 5, the levers 22a, 2
2b is tilted fully in the lowering direction to switch the remote control valves 21a and 21b to the lowering side. Therefore, the switching valves 6a and 6b are switched to the lowering side.

In this case, the pressure of the liquid from the liquid pressure supply source 28 acts on the switching valves 6a and 6b, but also acts on the pressure switches 26a and 26b. As a result, the pressure switches 26a and 26b are turned on, and electricity from the power supply 27 is supplied to the switching valve 24 via the pressure switches 26b and 26a.
And the switching valve 24 switches so that the main pipelines 7a and 7b communicate with each other. Therefore, the range in which the holding pressure of the main pipelines 7a, 7b is generated, that is, the hydraulic motors 2a, 2b and the unload valves 12a, 12b of the counter balance valves 15a, 15b.
12b communicates via a pressure equalizing line 23 to form a main line 7a,
7b is equalized and the constant horsepower control valve 18
a, 18b become equal, as a result, the opening of the regulating valves 19a, 19b becomes the same, and the hydraulic motors 2a,
The displacement capacity of 2b is the same. Therefore, even when the bucket 5 is lowered, the remote control valve 21
a, 21b without adjusting the hydraulic motors 2a, 2b.
Are synchronized and rotate at the same rotation speed, and the winch drum 1
a and 1b also rotate synchronously.

When the winch drums 1a and 1b rotate in synchronization, the rewind speed of the wire ropes 3a and 3b becomes the same, and the bucket 5 descends in a well-balanced posture.

The basic flow of the liquid during the lowering operation and the operation of the constant horsepower control valves 18a and 18b are the same as those in the conventional lowering operation, and thus the description thereof is omitted.

In the case of the winch drum driving hydraulic circuit of the present embodiment, when the bucket 5 is lowered, the lever 22a,
If 22b is fully tilted in the lowering direction, the rotation speeds of the hydraulic motors 2a and 2b are synchronized and there is no possibility that the hydraulic motors 2a and 2b will be overloaded due to unbalanced loads.

When the bucket 5 is lowered, the hydraulic motor 2
To synchronize the rotational speeds of the remote control valves 21a and 21b, the operator adjusts the rotation speed of the remote control valves 21a and 21b.
It is not necessary to adjust the remote control valves 21a and 21b by frequently operating the inclinations of the a and 22b, so that the burden on the operator is light and the fatigue is small.

Further, the load applied to the wire ropes 3a and 3b when the bucket 5 is lowered and the posture when the bucket 5 is lowered do not become unbalanced, and a stable operation can be performed.

Further, according to the present invention, the counter balance valves 15a, 15b are disconnected from the hydraulic motors 2a, 2b in the main pipelines 7a, 7b through which the liquid discharged from the hydraulic motors 2a, 2b flows when the bucket 5 is lowered. Load valves 12a, 12
b, a switching valve 24 is provided in the middle so as to connect the main pipelines 7a, 7b to each other.
The pressure switches 26a, 26 which are turned on by fully tilting the levers 22a, 22b of the a, 21b to the lowering side.
b, the switching valve 24 is switched only when both the pressure switches 26a and 26b are simultaneously turned on, so that a simple device can be added to perform the tuning operation at the time of the bucket 5 lowering operation. It can be easily applied to the winch drum drive hydraulic circuit, and the price is low.

It should be noted that the present invention is not limited to the above-described embodiment, but can be applied to other than a bucket. Of course, it can be operated only by pressure, and various changes can be made without departing from the gist of the present invention.

[0051]

According to the winch drum driving hydraulic circuit of the present invention, various excellent effects as described below can be obtained in any of claims 1 to 3. I) Overload due to uneven load at the time of bucket lowering can be prevented. II) Frequent speed adjustment at the time of bucket lowering is not required, and operator fatigue can be reduced. III) It is possible to prevent imbalance in the load due to the uneven load and the descending posture of the suspended body. IV) Equipment for tuning the hydraulic motor at the time of lowering can be easily and inexpensively added to the conventional apparatus.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating an example of an embodiment of a winch drum driving hydraulic circuit according to the present invention.

FIG. 2 is a circuit diagram illustrating an example of a conventional winch drum driving hydraulic circuit.

[Explanation of symbols]

 1a, 1b Winch drum 2a, 2b Hydraulic motor 3a, 3b Wire rope 5 Bucket (hanging body) 6a, 6b Switching valve (first switching valve) 7a, 7b Main pipeline (first main pipeline) 8a, 8b Main line (second main line) 9a, 9b Hydraulic pressure supply source 10a, 10b Tank 12a, 12b Unload valve 13a, 13b Check valve 15a, 15b Counter balance valve 18a, 18b Constant horsepower control valve 21a, 21b Remote control Valve 23 Equalizing line 24 Switching valve (second switching valve) 26a, 26b Pressure switch 27 Power supply

Claims (3)

[Claims] 1. A winch drum driving hydraulic system comprising a plurality of winch drum driving hydraulic systems. Each of the winch drum driving hydraulic systems drives a winch drum capable of winding and feeding a wire rope with a suspended body. And a liquid motor to supply the liquid to the suspension motor when the suspension is to be wound, and to supply the liquid discharged from the hydraulic motor when the suspension is to be lowered. A first main pipeline, and a second main line for supplying a liquid to a hydraulic motor when lowering the suspended body and supplying a liquid discharged from the hydraulic motor when winding the suspended body. A first main line and a first main line which are supplied with liquid from a hydraulic pressure supply source and which are switched to return the liquid from the second or first main line to the tank. A switching valve, and a hydraulic motor for supplying the liquid from the first switching valve when the suspension body is wound up. And a check valve that shuts off the liquid from the hydraulic motor when the hanging body is lowered, so as not to feed the liquid to the first switching valve side. An unload valve for generating a holding pressure in accordance with the pilot pressure of the second main line on the hydraulic motor side of the first main line for the liquid returning to the tank via the first main line and the switching valve. A counterbalance valve, which acts when the pressure on the hydraulic motor side of the first main line in the counterbalance valve reaches a set pressure and automatically adjusts the displacement of the hydraulic motor so as to maintain the set pressure. A constant horsepower control valve to be adjusted, and a single suspended body is wound by a plurality of winch drums.
A winch drum drive hydraulic circuit adapted to be lowered, wherein first main lines in each winch drum drive hydraulic system are closer to the hydraulic motor than the counter balance valve connection of the first main line. , A second switching valve connected to a middle part of the pressure equalizing pipe, and a first switching valve in each of the winch drum driving hydraulic systems. A switch means for switching the second switching valve so that the first main pipelines in each winch drum driving hydraulic system communicate with each other when switching to supply to the pressure motor. Drive hydraulic circuit. 2. The winch drum drive hydraulic circuit according to claim 1, wherein a remote control valve for switching the first switching valve for hoisting or lowering the suspension body is provided for each winch drum drive hydraulic system. 3. The remote control in each winch drum drive hydraulic system when the first switching valve of each winch drum drive hydraulic system is switched as a switch means in order to wind the suspension by a plurality of winch drums. Each winch drum is driven by a pressure switch that is turned on by the pressure of the liquid from the valve, supplies power from the power supply to the second switching valve via each system, and switches the second switching valve so that the first main lines communicate with each other. 3. The winch drum drive hydraulic circuit according to claim 1, wherein the hydraulic circuit is provided for each hydraulic system.