JPH07309590A - Control circuit for winch - Google Patents

Abstract

PURPOSE:To correctly detect that the tilt angle of a swash plate of a pump for winch is set at a neutral position. CONSTITUTION:The discharge direction of the pressurized liquid is changed by varying the tilt angle of the swash plate 30 of a pump 31 for winch by a cylinder 35 for varying the tilt angle, and the revolution direction of a winch drum driving motor 17 connected through a closed loop liquid passage 34 is changed, and the winding up and rewinding of a winch 7 are carried out, and a tilt angle neutral position detector 47 detects the differential pressure between the hydraulic chambers 38 and 39 on both the sides of the piston 37 of the tilt angle varying cylinder 35, and when the pressure becomes zero it is detected that the tilt angle of the swash plate 30 of the pump 31 for winch is set at a neutral position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winch control circuit.

[0002]

2. Description of the Related Art FIG. 2 shows a general crane 1.

A swivel unit 3 is provided on the upper part of a traveling unit 2 capable of traveling on the ground so as to be horizontally swivelable, and a jib 6 is vertically movable on the swivel unit 3 via a winch 4 and a wire rope 5. A hanging hook 9 is attached to the tip of the jib 6 so as to be able to move up and down via a winch 7 and a wire rope 8.

As shown in FIG. 3, the control circuit of the winch 4 in the crane 1 connects a pump 12 to a prime mover 10 such as a diesel engine via a gear unit 11, and connects the pump 12 to an open liquid passage 13 as shown in FIG. And switching valve 1
4, a winch winding side liquid passage 15 and a winch rewinding side liquid passage 16 are connected to a winch drum drive motor 17.

In the drawing, 18 is a winch drum, 19 is a load holding brake attached to the winch drum 18,
Reference numeral 20 is a suspended load suspended from the suspension hook 9.

Reference numeral 21 denotes a winch drum drive motor 17 which opens the winch winding side liquid passage 15 by the pressure of the pressurized liquid flowing in the winch winding side liquid passage 16 provided in the middle of the winch winding side liquid passage 15. A counter balance valve for discharging the pressure liquid, and 22 is a check valve connected in parallel with the counter balance valve 21.

Reference numeral 23 is a tank 25 connected to the switching valve 14.
To the return liquid passage 23, 24 is a relief valve for releasing the pressure liquid in the open liquid passage 13 to the return liquid passage 23, 26 is a suction passage from the tank 25 to the pump 12, and 27 is provided in the middle of the return liquid passage 23. A cooler 28 is a fan of the prime mover 10.

When operating the winch 7, first, the prime mover 10 such as a diesel engine is driven.

Then, the pump 12 connected to the prime mover 10 via the gear unit 11 is driven, and the pressurized liquid is sent from the pump 12 to the open liquid passage 13.

In the open liquid passage 13, when the switching valve 14 is in the neutral position, the pressure liquid from the pump 12 is released in the open liquid passage 1.
3. It is returned to the tank 25 via the return liquid passage 23, and is cooled by the fan 28 of the prime mover 10 in the cooler 27 partway.

At this time, the winch drum 18 is in a state in which the load holding brake 19 is applied in conjunction with the switching valve 14.

When the switching valve 14 is switched to the A side,
The load holding brake 19 interlocked with this is released, and the pressure liquid from the pump 12 is supplied to the winch drum drive motor 17 through the opening liquid passage 13, the winch winding side liquid passage 15, and the check valve 22. , Winch drum drive motor 1
7 is driven, the winch 7 winds up the wire rope 8, and the suspended load 20 is lifted.

The pressure liquid used to lift the suspended load 20 is
Then, it is returned from the winch drum drive motor 17 to the tank 25 via the winch rewinding side liquid passage 16 and the return liquid passage 23.

On the contrary, when the switching valve 14 is switched to the B side,
With the load holding brake 19 released, the pump 12
Pressure fluid from the open fluid path 13, winch rewind side fluid path 16
Is supplied to the winch drum drive motor 17 via the
Rewinds the wire rope 8 and the suspended load 20 is lowered.

The pressure liquid used for lowering the suspended load 20 is then supplied from the winch drum drive motor 17 to the winch winding side liquid passage 15, the counter balance valve 21, and the return liquid passage 2.
It is returned to the tank 25 via 3.

As described above, in the conventional control circuit of the winch 7, the operation timing of the load holding brake 19 attached to the winch drum 18 is linked to the switching timing of the switching valve 14 as described above. .

However, in recent years, as will be described later, a winch pump capable of changing the discharge direction of the pressure liquid by a swash plate is provided, and a winch in which the winch drum drive motor 17 is connected to the winch pump via a closed loop liquid passage. 7
Control circuits have been developed.

In such a control circuit for the winch 7, the tilt angle of the swash plate of the winch pump is changed by using a tilt angle changing cylinder or the like.

[0019]

However, the winch control circuit in which the winch pump and the winch drum drive motor 17 are provided in the closed loop liquid passage has the following problems.

That is, operations such as rotation, stop, and reverse rotation of the winch drum drive motor 17 are set by changing the tilt angle of the swash plate of the winch pump using the tilt angle changing cylinder. Since the tilt angle changing cylinder continuously changes the tilt angle, the winch drum drive motor 1 can be clearly defined like the switching valve 14 in FIG.
It is not possible to grasp the timing when 7 stops, that is, the timing when the tilt angle reaches the neutral position.

Therefore, the load holding brake 1 of the winch 7
There is a problem that the operation timing of 9 can no longer be controlled.

In view of the above situation, it is an object of the present invention to provide a winch control circuit capable of accurately detecting that the tilt angle of the swash plate of the winch pump is in the neutral position. To do.

[0023]

According to the present invention, a winch drum drive motor is connected via a closed loop liquid passage to a winch pump whose swash plate can change the discharge direction of pressure fluid, and the winch pump is used as a swash plate. Connect the tilt angle changing cylinder and detect the differential pressure between the hydraulic chambers on both sides of the tilt angle changing cylinder piston to obtain the tilt angle neutral position of the swash plate of the winch pump. The present invention relates to a winch control circuit characterized in that a position detector is provided.

[0024]

The operation of the present invention is as follows.

By changing the tilt angle of the swash plate of the winch pump by the tilt angle changing cylinder, the discharge direction of the pressure liquid is changed, and the rotation direction of the winch drum drive motor connected through the closed loop liquid passage. Is changed, and the winch is wound and rewound.

The tilt angle neutral position detector detects the differential pressure between the hydraulic chambers on both sides of the piston of the tilt angle changing cylinder, and when the differential pressure becomes zero, the swash plate of the winch pump is operated. It is detected that the tilt angle is in the neutral position.

[0027]

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

FIG. 1 shows an embodiment of the present invention.

Since the structure of the crane itself is the same as that of FIG. 2, refer to FIG. 2 as necessary.

In the figure, 7 is a winch, 8 is a wire rope wound around the winch 7, 9 is a hanging hook attached to the tip of the wire rope 8, 10 is a prime mover such as a diesel engine, and 11 is a prime mover 10. Gears, 1
7 is a winch drum drive motor, 18 is a winch drum, 19 is a load holding brake attached to the winch drum 18, 20 is a suspended load suspended from a suspension hook 9, 25
Is a tank, and 28 is a fan of the prime mover 10.

In the present invention, the governor 29 for constant speed operation is mounted on the prime mover 10 for controlling the prime mover 10 so that the prime mover 10 is driven while maintaining a predetermined speed range.

Further, a winch pump 31 capable of changing the pressure liquid discharge direction by a swash plate 30 is connected to the gear device 11, and a winch winding is provided between the winch pump 31 and the winch drum drive motor 17. Connection is made by a closed loop liquid passage 34 composed of the intake side liquid passage 32 and the winch rewinding side liquid passage 33.

The swash plate 30 of the winch pump 31
The rod 36 of the tilt angle changing cylinder 35 is attached to the hydraulic pressure chambers 38 and 39 on both sides of the piston 37 of the tilt angle changing cylinder 35, and the tank 25 and the control pressure liquid supply open liquid passage 40. In addition, a switching valve 41 capable of selectively communicating these
Is connected to the switching valve 41, and the control pressure liquid supply opening liquid passages 43 and 44 provided with the operation lever 42 are connected.

Further, the tilt angle neutral position of the shuttle valve 46 or the like in which the valve body 45 is moved in the hydraulic chambers 38 and 39 on both sides of the piston 37 of the tilt angle changing cylinder 35 in accordance with the pressure of both. The load holding brake 19 is provided with a detector 47, and the tilt angle neutral position detector 47 assumes that the tilt angle becomes the neutral position when the valve body 45 reaches the intermediate position.
The switch device 49 for sending the operation signal 48 to the switching valve 51 for operating the brake cylinder 50 is attached.

Next, the operation will be described.

The operation of the crane is the same as that shown in FIG.

When operating a crane, a prime mover 10 such as a diesel engine is driven.

Then, the winch pump 31 connected to the prime mover 10 via the gear unit 11 is driven, and the winch pump 31 discharges the pressure liquid.

Since the governor 29 for constant speed operation is attached to the prime mover 10, the governor 29 for constant speed operation is attached.
However, depending on the fluctuation of the load such as the winch pump 31,
The output of the prime mover 10 is adjusted and controlled so as to be within a predetermined speed range.

In the winch pump 31, when the operating lever 42 is at the stop position, the switching valve 41 is at the neutral position, and the hydraulic chambers 38 and 39 on both sides of the piston 37 of the tilt angle changing cylinder 35 are provided. Since the acting pressures are equal, the swash plate 30 is held at 0 degree, and the pressurized liquid is not discharged from the winch pump 31.

When the operating lever 42 is tilted to the winding side, the pressure liquid acts on the A side of the switching valve 41 via the control pressure liquid supply opening liquid passage 43, and the switching valve 41 is switched to the A side. While the pressure liquid from the control pressure liquid supply opening liquid passage 40 enters the hydraulic pressure chamber 39 side of the tilt angle changing cylinder 35, the pressure liquid in the hydraulic pressure chamber 38 escapes to the tank 25 and the swash plate 30 tilts. The
The pressure liquid from the winch pump 31 is discharged to the winch winding side liquid passage 32 and supplied to the winch drum drive motor 17, and the winch drum drive motor 17 is driven,
The winch 7 winds the wire rope 8 and the suspended load 20
Will be hung up.

The pressure liquid that has driven the winch drum drive motor 17 then exits from the winch drum drive motor 17 and enters the winch rewind side liquid passage 33, and the winch pump 3
1, is discharged to the winch winding side liquid passage 32 again, and is circulated and used.

On the contrary, when the operation lever 42 is tilted to the rewinding side, the pressure fluid acts on the B side of the switching valve 41 through the control pressure fluid supply opening fluid passage 44 to switch the switching valve 41 to the B side. Therefore, the pressure liquid from the control pressure liquid supply opening liquid passage 40 enters the hydraulic pressure chamber 38 side of the tilt angle changing cylinder 35, and the pressure liquid in the hydraulic pressure chamber 39 escapes to the tank 25 so that the swash plate 30 is removed. On the contrary, the winch pump 31 is rotated in the same direction and the discharge direction of the pressure liquid is changed to the winch rewind side liquid passage 33 side, so that the pressure liquid flows from the winch rewind side liquid passage 33 to the winch drum drive motor 17 The winch drum drive motor 17 is reversed, the winch 7 rewinds the wire rope 8, and the suspended load 20 is lowered.

The pressure liquid that has come out of the winch drum drive motor 17 then comes out of the winch drum drive motor 17 and enters the winch winding side liquid passage 32, is sucked into the winch pump 31 and again becomes the winch rewinding side liquid passage. It is discharged to 33 and is recycled.

Since potential energy acts on the suspended load 20 when the wire rope 8 is unwound, a rotational force is generated in the winch drum drive motor 17 due to the potential energy, and the winch drum drive motor 17 is closed loop liquid. Road 3
4 is connected to the winch pump 31 via the winch winding side liquid passage 32, and a driving force is generated in the winch pump 31 by the potential energy of the suspended load 20.

Then, the driving force of the winch pump 31 causes the winch pump 31 to pass through the gear unit 11.
The driving force is transmitted to the prime mover 10 and the like connected to the.

Therefore, the winch pump 3 is attached to the prime mover 10.
Since the driving force from 1 will be added,
The load on the prime mover 10 is lightened, the governor 29 for constant speed operation reduces the output of the prime mover 10, and the fuel supplied to the prime mover 10 is saved.

As described above, when the winch pump 31 and the winch drum drive motor 17 are connected by the closed loop liquid passage 34, there is an advantage that energy can be saved. However, as in the conventional case, the operation lever 42 is used. Even if the changeover valve 41 and the movement of the switching valve 41 are detected, the tilt angle changing cylinder 35 has a response delay. Therefore, when the operation lever 42 is switched to the stop position, the swash plate 30 of the winch pump 31 is It is not always at the tilt angle neutral position, and it is difficult to accurately detect the timing.

Therefore, in the present invention, the tilting angle neutral position detector 47 such as the shuttle valve 46 is provided in the hydraulic pressure chambers 38 and 39 on both sides of the piston 37 of the tilting angle changing cylinder 35, and the hydraulic pressure chambers 38 and 39 are provided. The valve body 45 is moved according to the pressure of 39, and the time when the tilt angle neutral position is reached is detected depending on the position of the valve body 45.

Therefore, when the valve body 45 of the tilt angle neutral position detector 47 reaches the intermediate position, the switch device 49 sends the operation signal 48 to the switching valve 51 to switch the switching valve 51 to the D side. By extending the brake cylinder 50, the operation of the load holding brake 19 can be performed at an accurate timing and other control can be performed.

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0052]

As described above, according to the winch control circuit of the present invention, it is possible to accurately detect that the tilt angle of the swash plate of the winch pump is in the neutral position. It can be effective.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of an embodiment of the present invention.

FIG. 2 is an outline view of a general crane.

FIG. 3 is a schematic system diagram of a conventional example.

[Explanation of symbols]

 17 Winch Drum Drive Motor 30 Swash Plate 31 Winch Pump 34 Closed Loop Fluid Path 35 Tilt Angle Change Cylinder 37 Pistons 38, 39 Hydraulic Chamber 47 Tilt Angle Neutral Position Detector

Claims (1)

[Claims] 1. A winch drum drive motor is connected to a winch pump whose swash plate can change the discharge direction of pressure fluid through a closed loop liquid passage, and a tilt angle changing cylinder is connected to the swash plate of the winch pump. The tilt angle neutral position detector is provided in the hydraulic chambers on both sides of the piston of the tilt angle changing cylinder to detect the differential pressure between the two and detect the tilt angle neutral position of the swash plate of the winch pump. Characteristic winch control circuit.