JPS61183093A - Control circuit for hydraulic winch - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a v-control circuit for a hydraulic winch in a crane.

(Prior art) Conventionally, in a hydraulic winch, there is a device that enables hoisting, lowering, neutral automatic stop, and neutral free descent by operating a single hoisting lever, for example, in Japanese Patent Application Laid-Open No. 58-1.
There is one as shown in Japanese Patent No. 3089. By holding the first switching valve in the first position, this device operates the hoisting lever to switch the main switching valve and rotate the hydraulic motor in the hoisting or hoisting direction. , second,
The third switching valve is switched, the negative clutch cylinder is communicated with the tank via the second switching valve, and the clutch is turned on. At the same time, pressure oil is supplied from the operating hydraulic pressure source to the negative brake cylinder via the third switching valve. is supplied to turn off the negative brake and rotate the winch drum in the hoisting or hoisting direction. When the hoisting lever is returned to the neutral position, the second and third switching valves are returned to their original positions, and the negative clutch cylinder is connected to the tank via the second switching valve and the first switching valve. At the same time, the negative brake cylinder is communicated with the tank via the third switching valve and the first switching valve to turn on the negative brake and automatically stop the winch drum. In addition, by switching the first switching valve to the second position, the winch drum can be rotated by the same operation as above during hoisting or hoisting operation, and when the hoisting lever is returned to the neutral position, the 2. Return the third switching valve to its original position, and supply pressure oil from the operating hydraulic source to the negative clutch cylinder via the first switching valve and the second switching valve to turn off the negative clutch. Pressure oil is supplied from the hydraulic pressure source to the negative brake cylinder via the first switching valve and the third switching valve to turn off the negative brake and allow the negative brake to freely descend.

However, in this device, the second and third switching valves, which are switched by the hoisting lever, are provided on the secondary side of the first switching valve for selecting between neutral automatic stop and neutral free descent. Even if neutral automatic stop or neutral free descent is selected in advance using the first switching valve, the primary side circuits of the second and third switching valves are switched by operating the hoisting lever.
As a result, the pressure oil supply and discharge paths to and from the negative clutch cylinder and negative brake cylinder change, and at the transitional position, the primary and secondary sides of the second and third switching valves are temporarily separated. However, there were problems such as unstable operation of the negative clutch and negative brake.

(Purpose of the Invention) The present invention was made to solve such problems, and allows for hoisting and shipping of shipments by simply operating a single hoisting lever.
The present invention provides a control circuit for a hydraulic winch that allows each operation of lowering, neutral automatic stop, and neutral free descent to be performed as desired, and also improves safety by improving operational stability.

(Structure of the Invention) The present invention includes a main switching valve that is switched by operating a hoisting lever, a hydraulic motor for a winch whose rotation direction is switched by switching the main switching valve, and a hydraulic motor that is biased by a spring in a direction to connect a clutch. A negative clutch cylinder that is operated in the direction of releasing the clutch by introducing pressure oil, a winch drum to which the rotation of the hydraulic motor is transmitted by the negative clutch cylinder, and a winch drum that is moved in the direction of tA by operating the brake pedal. A positive brake that is activated, a negative brake cylinder that is biased by a spring in the direction of braking the winch drum and activated in the direction of releasing the υ1 movement by introducing pressure oil, and a first circuit when the hoisting lever is in the neutral position. is held in a position where the is connected to the operating hydraulic pressure source and the second circuit is communicated with the tank, and when the hoisting lever is operated, the first circuit is communicated with the tank and the second circuit is connected to the operating hydraulic source. an auxiliary switching valve that can be switched to the tank, a third circuit that is always connected to the operating hydraulic pressure source, and a position where the negative clutch circuit connected to the negative clutch cylinder is connected to the tank and the first circuit. A selection valve that can be freely switched between a position where the negative brake circuit connected to the negative brake cylinder is communicated with the second circuit and a position where the negative brake circuit connected to the negative brake cylinder is communicated with the second circuit is provided. It is characterized by the fact that

(Example) In the figure, 1 is a main hydraulic pump, and its discharge circuit 2 is connected to both side circuits 4 of a winch hydraulic motor 5 via a main switching valve 3.
．． 6 and a return circuit 7 to the tank 8 are switchably connected. 9 is a counter balance valve. 10.11 is a remote control valve for switching the main switching valve 3, and its -
An operating hydraulic pump 14 is connected to the next side via a circuit 12 and a relief valve 13, and the primary pressure determined by the relief valve 13 is introduced, and by operating the hoisting lever 15, the secondary side circuit 16.17 A switching pilot pressure is derived, and the pilot pressure switches the main switching valve 3 from the neutral position 3C to the upper hoisting position 13a or the lower hoisting position 3b.

A drum shaft 19 is connected to the output shaft of the hydraulic motor 5 via a reduction gear r18, and a winch drum 20 is rotatably fitted onto the drum shaft 19. Reference numeral 21 denotes a cylinder of the positive brake 22, which is biased by a spring in the direction of releasing the positive brake 22, and is activated by the positive brake circuit 23.
The drum 20 is operated in the direction of braking by introducing pressure oil from the drum 20. A secondary side of a pressure reducing valve 25 operated by a brake pedal 24 is connected to the positive brake circuit 23, and a primary side of the pressure reducing valve 25 is connected to the circuit 12.

Reference numeral 26 denotes a cylinder of the negative clutch 27, which is biased by a spring in the direction of connecting the negative clutch 27, and when pressure oil is introduced from the negative clutch circuit 28, the negative clutch 27 is connected.
7 is operated in the direction of releasing it. 29 is negative brake 3
The cylinder 0 is biased by a spring in the direction of braking the drum 20, and is operated in the direction of releasing the negative brake 30 by introducing pressure oil from the negative brake circuit 31.

32 is a first selection valve that connects the negative clutch circuit 28 to the tank 8.
It is possible to freely switch between a position 32a where the first circuit 33 is communicated with the negative clutch circuit 28 and a position 32b where the first circuit 33 is communicated with the negative clutch circuit 28. Reference numeral 34 designates a second selection valve, with a valve 1f 35a connecting the second circuit 35 to the negative brake circuit 28 and a valve 113 connecting the third circuit 36 to the negative brake circuit 31.
2b. The first circuit 33 and the second circuit
The circuit 35 is switchably connected to the discharge circuit 38 of the operating hydraulic pump 14 and the return circuit 39 to the tank 8 via an auxiliary switching valve 37, and the second circuit 34 is always connected to the operating hydraulic pump 14. has been done. Further, the auxiliary switching valve 37 is switched by the switching pilot pressure from the remote control valves 10 and 11, and is in its neutral position! 37G to connect the circuit 33 to the circuit 38 and the circuit 35 to the circuit 39,
Left and right places [378, 37b, the above circuit 33 is connected to circuit 39
In addition, the circuit 35 is connected to the circuit 38, respectively. However, in this case, the switching setting pressure Pi1 of the auxiliary switching valve 35 is set smaller than the switching setting pressure Pi2 of the main switching valve 3 (.

Next, the operation of the above circuit will be explained.

First, when the 131st selection valve 32 is at the illustrated position H32a, the negative clutch cylinder 26 is communicated with the tank 8 via the negative clutch circuit 28 and the first selection valve 32, regardless of the position of the auxiliary switching valve 37. Negative clutch 27 is turned on. On the other hand, when the second selection valve 34 is held at the illustrated position 32a and the hoisting lever 15 is at the neutral position, the auxiliary switching valve 37 is at the neutral position 37c, and the negative brake cylinder 29 is connected to the negative brake circuit 31. , the second selection valve 32, the first circuit 33, the auxiliary switching valve 37, and the return circuit 37 to communicate with the tank 8, and the negative brake 30 is turned on.

In this state, when the hoisting lever 15 is operated in the hoisting direction, a switching pilot pressure is derived from the remote control valve 10 to the circuit 16, and the pilot pressure first causes the auxiliary switching valve 37 to
is switched to the left position 37a in the drawing. As a result, the operation hydraulic pump 14 is connected to the circuit 36, the auxiliary switching valve 37, the second circuit 35, the second selection valve 34, and the negative brake circuit 31.
Pressure oil is supplied to the negative brake cylinder 29 via the negative brake cylinder 29, and the negative brake 30 is turned off. After that, the main switching valve 3 is switched to the upper winding 15 by the pilot pressure from the remote control valve 10.
t3a, and accordingly, pressure oil is supplied from the main hydraulic pump 1 to the hydraulic motor 5 via the circuit 2, the main switching valve 3, the circuit 4, and the counterbalance valve 9, and the motor 5 rotates in the hoisting direction. It is accelerated and the rotational force is transmitted to the winch drum 20 via the reduction gear 18, the drum shaft 19, and the negative clutch 27.
The drum 20 is rotated in the hoisting direction, and hoisting operation for shipping is performed.

During this hoisting operation, the main switching valve 3 is switched immediately after the auxiliary switching valve 37 is switched, so the negative brake 30 is turned off before the hydraulic motor 5 is driven to rotate. , the first selection valve 32 is in the illustrated position 32
a, the negative clutch continues to be turned on, and the hydraulic motor 5 is kept stopped by the counterbalance valve 9, so even if the negative brake 30 is turned off first. There is no risk of the suspended load falling. After that, the pilot pressure led to the circuit 16 is controlled according to the operating angle of the hoisting lever 15, and the spool opening of the main switching valve 3 is controlled by the pilot pressure, so that the pressure oil supply flow to the hydraulic motor 5 is controlled. ff1 (rotation speed)! IJIj is done.

Therefore, depending on the operating angle of the hoisting lever 15, the hoisting speed can be adjusted arbitrarily.

Next, when the hoisting lever 15 is returned to the neutral position, the main switching valve 3 is first returned to the neutral position f13c, the supply of pressure oil from the main hydraulic pump 1 to the hydraulic motor 5 is gradually reduced and stopped, and the hydraulic motor 5 is After being gradually decelerated and stopped, the auxiliary switching valve 37 is returned to the neutral position 37C, so that the negative brake cylinder 29 is connected to the negative brake circuit 31, the second selection valve 34, the second circuit 35, and the auxiliary switching valve 37. , return circuit 39
The negative brake 30 is turned on, the winch drum 20 is stopped, and shipping is stopped and held. In this case, the auxiliary switching valve 37 is returned to the neutral position 137c after the main switching valve 3 is returned to the 11 standing position @3C, so the hydraulic motor 5 is stopped before the negative brake 30 is turned on. Since the clutch remains on, there is no risk of the suspended load falling even if the hydraulic motor 5 is stopped first, and since the negative brake 30 is turned on after the hydraulic motor 5 is decelerated and stopped, the winch drum 20 is stopped smoothly.

Further, when performing power hoisting operation of a suspended load, the hoisting lever 15 may be tilted in the hoisting direction while holding the selection valves 32, 34 at the positions shown in the figure @32a, 34a. As a result, the negative clutch remains on as described above, the auxiliary switching valve 37 is switched to the drawing position [37b, the negative brake 30 is turned off, and then the main switching valve 3 is switched to the lowering position 3b and the hydraulic pressure is The motor is rotationally accelerated in the lowering direction, the winch drum 20 is rotated in the lowering direction, and a powered lowering operation of the suspended load is performed.

That is, when performing normal hoisting and hoisting operations, by holding each selection valve 32, 34 in the illustrated position 32a, 34a, the negative clutch 27 remains automatically turned on, and the following operations are performed. When the hoisting lever 15 is operated in the hoisting direction A or the hoisting down direction B, the auxiliary switching valve 37 moves to the left position 37 in the figure.
a or the right position 37b and the negative brake 30
is turned off, the main switching valve 3 is switched to the upper hoisting position 1Ff3a or the lower hoisting position ta3b, the hydraulic motor 5 and the winch drum 20 are rotated in the lowering direction or lowering direction, and the suspended load is hoisted or lowered. When operation is performed and the hoisting lever 15 is returned to the neutral position, the main switching valve 3 is returned to the neutral position 3C, the hydraulic motor 5 is decelerated and stopped, and the auxiliary switching valve 37 is returned to the neutral position R37c. The negative brake 30 is turned on, and the winch drum 20, that is, the suspended load is automatically stopped, and thereby, by simply operating the hoisting lever 15, hoisting and hoisting operations with high safety can be performed using a so-called neutral automatic stop method. I can do it.

Next, each selection valve 32.34 is connected to the top ff132b in the drawing.

34b, the negative clutch circuit 28 is communicated with the first circuit 33, and the negative brake circuit 31 is communicated with the third circuit 36. As a result, pressure oil is supplied to the negative brake cylinder 29 from the operating hydraulic pump 14 via the third circuit 36, the second selection valve 34, and the negative brake circuit 31, regardless of the position of the auxiliary switching valve 37.
Negative brake 30 is turned off. In this state, when the hoisting lever 15 is in the neutral position, the auxiliary switching valve 37
is in the neutral position 1f37c, and the negative clutch cylinder 26
Meanwhile, pressure oil is supplied from the operation hydraulic pump 14 through the circuit 38, the auxiliary switching valve 37, the first circuit 33, the first selection valve 32, and the negative clutch circuit 28, and the negative clutch 27 is turned off. Then, the winch drum 20 is attached to the drum shaft 19.
The suspended load is free to fall. Furthermore, when the brake pedal 24 is depressed during this free descent, pressure oil is supplied from the pressure reducing valve 25 to the positive brake cylinder 21 via the circuit 23, the positive brake 22 is turned on, and the free descent of the suspended load is stopped. When the pressing force on the pedal 22 is released, the positive brake cylinder 21 is communicated with the tank 8, the positive brake 22 is turned off, and the suspended load is freely lowered.

Therefore, each selection valve 32.34 is placed in the upper part of the drawing 1t32b.

34b and the hoisting lever 15 at the neutral position, shipping can be freely lowered and stopped simply by operating the brake pedal 24. Furthermore, during this free descent, the main switching valve 3 is in the neutral position f13c, so the hydraulic motor 5 is stopped and no power loss occurs.

Next, the respective selection valves 32 and 34 are moved to positions 32b and 32b on the drawing, respectively.
34b, move the hoisting lever 15 in the hoisting direction A.
When operated, the pilot circuit 16 from the remote control valve 10
A pilot pressure for li7JM is derived, and the pilot pressure first switches the auxiliary switching valve 37 to fa37a, which is located in the drawing. As a result, negative clutch cylinder 2
6 is communicated with the tank 8 via the negative clutch circuit 28, the first selection valve 32, the first circuit 33, the auxiliary switching valve 37, and the circuit 39, and the negative clutch 27 is turned on. Note that the negative brake 30 remains off regardless of the operation of the hoisting lever 15. Accordingly, the main switching valve 3 is switched to the upper hoisting position 1!3a by the pilot pressure from the remote control valve 10, and from then on, pressure is applied from the main hydraulic pump 1 to the hydraulic motor 5 in the same way as during the normal hoisting operation. Oil is supplied, the motor 5 is rotationally accelerated in the hoisting direction, the rotational force is transmitted to the winch drum 20 via the negative clutch 27, etc., the drum 20 is rotated in the hoisting direction, and the suspended load is hoisted. Top operation is performed.

Therefore, as in clamshell work, the free fall of a suspended load,
When stopping and hoisting operations are repeated, as described above, with each selection valve 32, 34 switched to the upper position in the drawing @ 32b, 34b, the hoisting lever 15 is set to neutral, so that the negative clutch 27 and the negative brake are switched off. 30 to freely lower the suspended load, then turn on the positive brake 22 with the brake pedal 24 to stop the suspended load, and then operate the hoisting lever 15 in the hoisting direction A. The negative clutch 27 is turned on to perform hoisting operation for shipping. In this way, the suspended load can be freely lowered, stopped, and hoisted by operating the hoisting lever 15 and brake pedal 24.

By the way, in the above embodiment, the hoisting lever 15 operates the remote control valves io and 11, and the secondary pressure is used to switch the main switching valve 3 and the auxiliary switching valve 37. The main switching valve 3 may be switched mechanically or electrically.
The auxiliary switching valve 37 may be switched mechanically or electrically in conjunction with the switching of the auxiliary switching valve 3 by extracting pilot pressure from the circuits 4 and 6 on both sides of the hydraulic motor 5.
7 may be switched.

Further, it is also possible to easily configure the selection valves 32 and 34 into one, and in this way, the circuit configuration can be simplified and costs can be reduced.

(Effects of the Invention) As described above, the present invention provides free descent that prevents power loss by switching the work selection valve, repetitive work of the free descent and hoisting operation, and safety of the hoisting lever neutral automatic stop system. It is possible to freely select between hoisting and hoisting operations, which are rich in speed, and improve work efficiency. Switching from operation to neutral automatic braking and vice versa, as well as from hoisting operation to neutral free descent and vice versa, can always be performed smoothly, resulting in stability and It is very safe.

[Brief explanation of the drawing]

The figure is a hydraulic circuit diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Main hydraulic pump, 3... Main switching valve, 5... Hydraulic motor for winch, 8... Tank, "to, ii...
...Remote control valve, 14...Hydraulic pump for operation, 15.
...Hoisting lever, 20...Winch drum, 22...
- Body brake, 24... Brake pedal, 26...
・Negative clutch cylinder, 27...Negative clutch, 2
8... Negative clutch circuit, 29... Negative brake cylinder, 30... Negative brake, 31... Negative brake circuit, 32... Work selection valve, 33... First circuit, 34... ...Second circuit, 37...Auxiliary switching valve.

Claims (1)

[Claims] 1. A main switching valve that can be switched by operating the hoisting lever;
A winch hydraulic motor whose rotation direction can be switched by switching the main switching valve, a negative clutch cylinder which is biased by a spring in the direction of connecting the clutch and is operated in the direction of releasing the clutch by introducing pressure oil, and this negative clutch. A winch drum to which the rotation of the hydraulic motor is transmitted by a cylinder, a positive brake that is operated in the direction of braking the winch drum by operating the brake pedal, and a spring that is biased in the direction of braking the winch drum and introduction of pressure oil. a negative brake cylinder operated in the direction of releasing braking by the hoisting lever; and a hoisting lever held in a position where the first circuit is connected to the operating hydraulic pressure source and the second circuit is communicated with the tank when the hoisting lever is in the neutral state. an auxiliary switching valve that is switched to a position where the first circuit is connected to the tank and the second circuit is connected to the operating hydraulic power source during operation; and a third circuit that is constantly connected to the operating hydraulic power source. , a selection valve that can freely switch between a position where the negative clutch circuit connected to the negative clutch cylinder is communicated with the tank and a position where the negative brake circuit connected to the negative brake cylinder is communicated with the first circuit; A control circuit for a hydraulic winch, comprising a selection valve that can be freely switched between a position communicating with the circuit and a position communicating with a third circuit.