JPS6181392A - Hydraulic circuit for hydraulic winch - Google Patents

Abstract

(57) [Summary] 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 free 7-all (
The present invention relates to a hydraulic circuit for a hydraulic winch capable of free fall. Specifically, the present invention relates to a hydraulic circuit for a hydraulic winch that has a negative brake function and a positive brake function that can be selected by hydraulic pressure without using a mechanical brake device or a clutch device.

[Conventional technology]

A conventional hydraulic winch includes a clutch device that transmits power from a hydraulic motor and a brake device that holds and stops a suspended load.

This brake device is roughly divided into a counterbalance valve for lowering a suspended load with power, and a band brake for stopping a suspended load from free fall when the clutch is OFF.
The combination of F corresponds to negative brake and positive brake. In the case of a negative brake, the clutch is always ON during power hoisting, movable hoisting, and stopping, and when stopping, the band brake is also automatically turned ON to hold the suspended load. On the other hand, in the case of a body brake, the clutch is ON when the hoist is being hoisted up or when the hoist is being hoisted down, but when the hoist is stopped (when the hoisting lever is in the neutral position), the clutch is turned off and the load is allowed to free fall. At this time, the load can be stopped and held by stepping on the band brake. Negative brakes are generally used for normal crane work, and positive brakes are generally used for packet work (clamshell dragline work).

However, the above-mentioned hydraulic winch requires a very complicated control hydraulic circuit, a mechanical latch device, and a band brake device in order to support both negative brakes and positive brakes. Furthermore, clutch linings and brake linings require constant maintenance, and failure to do so may directly lead to a serious accident. In addition, current band brakes are subject to heavy load conditions (squeaking noises may be generated and cause noise pollution), and they may not be able to handle high temperatures during heavy work, and lack braking power (brakes may slip). ) and damage to the hoisting drum (line scratches), and improvements are desired.

[Problem that the invention seeks to solve]

The present invention aims to provide a hydraulic circuit for a hydraulic winch that solves the above-mentioned problems.

[Means for solving problems]

The present invention takes the following measures to solve the above-mentioned problems. That is, a variable throttle valve is provided in parallel between the hydraulic motor and the counterbalance valve, a brake operating device is linked to the variable throttle valve, a switching valve is connected to the pilot valve, and the switching valve is connected to the variable throttle valve. Connect in series to the variable throttle valve.

[Effect]

The hydraulic circuit of the hydraulic winch of the present invention can be selected for positive braking by locking the brake operating device, and for positive braking by unlocking the brake operating device.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic circuit for a hydraulic winch according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the hydraulic circuit of the hydraulic winch of the present invention.

FIG. 2 is a side view of a crawler crane using the hydraulic winch hydraulic circuit of the present invention.

In FIG. 2, reference numeral 16 is the crane body. This crane main body 16 has built-in a hydraulic circuit of the present invention, which will be described later, and a hoisting drum 13 driven by the hydraulic circuit of the present invention. A base end of a jib 17 is attached to the front part of the crane body 16 so as to be able to rise and fall.

A hoisting rope 18 wound around the hoisting drum 13 is wound around the tip of the jib 17. A suspended load 19 is suspended from the tip of the hoisting rope 18.

As shown in FIG. 1, the hydraulic circuit of the hydraulic winch of the present invention in this embodiment includes a boost hydraulic pump 1, a hydraulic motor drive hydraulic pump 2, and a pilot hydraulic pump 3.

A boost relief valve 4 is connected to the boost hydraulic pump 1 to keep the pressure of the hydraulic pump 1 constant (generally a low pressure of about 50 liters since it is used for boost). On the other hand, a pilot relief valve 5 is connected to the pilot hydraulic pump 3 to keep the pressure of the hydraulic pump 3 constant (approximately 50 to 100 to 1,000 psi for pilot use). A pilot valve 6 is connected to this pilot hydraulic pump 3. This pilot valve 6 is connected to a hoisting lever 6', and when the hoisting lever 6' is operated to the "hoisting" side, pressure oil from the hydraulic pump 3 is transferred to the A port side of a shuttle valve 7 and a directional control valve 8, which will be described later. When the hoisting boat 6a is sent to the control section of It consists of a lowering boat 6b that is sent to the control section.

A shuttle valve 7 is connected to the hoisting boat 6a and the hoisting boat 6b of the pilot valve 6. This shuttle valve 7 sends the high pressure side of the control oil of the pilot valve 6 to a switching valve 15 which will be described later. The hydraulic motor drive pump 2 is connected to the directional control valve 8 on the input side, and the hoisting boat 6a and lowering boat 6b of the pilot valve 6 are connected to the control section of the directional control valve 80A on the boat side and the boat B side. control unit is connected. When pilot pressure is applied to the control section on the A boat side, this directional switching valve 8 switches to the A boat and the B boat.
When pilot pressure is applied to the control section on the boat side, the boat is switched to B boat, and the direction of the pressure oil from the hydraulic pump 2 is switched.

The outlet side of the directional switching valve 8 is connected to the inlet side of a counterbalance valve 9. This counterbalance valve 9 consists of a relief valve 9a, a pressure regulating valve 9b, and a check valve 9C, and controls the pressure 11 opening a61-81392 (3) oil between the directional control valve 8 and the hydraulic motor 11, which will be described later. . The A side and B side of a hydraulic motor 11 are connected to the outlet side of the counterbalance valve 9, and a hoisting drum 13 is directly connected to the rotating shaft of the hydraulic motor 11. This hydraulic motor 11 is driven by pressure oil from the hydraulic pump 2 for driving the hydraulic motor, and drives the winding hydraulic drum 13 . A check valve 10 is connected between the B side of the hydraulic motor 11 (the suction port side is the same in free fall) and the boost hydraulic pump 1, and the check valve 10 is connected to the B side of the hydraulic motor 11. It is configured so that the boost is applied through the This check valve 10 prevents the pressure oil of the hydraulic motor 11 from flowing back into the hydraulic pump 1.

A variable throttle valve 12 is differentially provided between the counterbalance valve 9 and the hydraulic motor 11. A brake pedal 14 is attached to this variable throttle valve 12.
4'. This variable throttle valve 12 is
The movement of the brake pedal 14 is transmitted via the brake link 14' and throttles the circuit in proportion to the displacement of the brake pedal 14. 1, this throttle valve 12 performs pressure compensation and temperature compensation, and is not affected by load level or viscosity change, and can obtain a flow rate characteristic proportional to the displacement of the brake pedal 14. The throttle valve 12 is rotated back by a spring, and when the brake pedal 14 is released, it returns to the fully open position.
When the brake pedal 14 is depressed to its full stroke, it is fully closed. Furthermore, D of the upstream side, that is, the switching valve 15 to be described later.
The pressure at section D is used as a pilot pressure and is guided to the opposite side of the brake pedal force.As the pressure at section D increases, the pressure at which the brake pedal 14 is depressed becomes heavier. This brake pedal 14 is equipped with a locking device (not shown). A switching valve 15 is connected in series upstream of the variable throttle valve 12, and a shuttle valve 7 is connected to a control section of the switching valve 15. Pressure oil from the pilot valve 6 acts on the switching valve 15 through the shuttle valve 7 to switch the boat. When the hoisting lever 6' is in the neutral position, it becomes the D port, and the A side and B side of the hoisting motor 11 communicate with each other.

When the hoisting lever 6' is operated, the boat is switched to the C boat, and the A side and B side of the hoisting motor 11 are cut off.

The hydraulic circuit of the hydraulic winch of the present invention in this embodiment has the configuration as described above), and its operation will be described below.

First, by operating the negative brake (hoisting lever 6') the suspended load 19
When the hoisting lever 6' is in the neutral position, the suspended load is held. ), brake pedal 1
Depress 4 and mechanically lock 1'.

Then, the variable throttle valve 12 is completely blocked, and no pressure oil flows through the variable throttle valve 12. In this state, when the hoisting lever 6' is moved to the hoisting side (B side), the pressure oil of the hydraulic pump 3 flows from the hoisting boat 6a of the pilot valve 6 to the A boat side control section of the direction switching valve 8, and the The switching valve 8 switches to the A boat. At this time, the pressure oil passes through the shuttle valve 7 and the switching valve 15.
The switching valve 15 also switches to the C boat. Therefore, in the figure, the area between X and Y is blocked by the variable throttle valve 12 and the switching valve 15. Therefore, pressure oil does not flow in the direction of the dashed-dotted line arrow. On the other hand, the pressure oil of the hydraulic pump 2 flows from the A boat of the directional control valve 8 in the direction of the solid line arrow, passes through the check valve 9c of the counterbalance valve 9, enters the hydraulic motor 11 from the A side of the hydraulic motor 11, and enters the hydraulic motor 11 from the B side. It exits, passes through the directional control valve 8, and returns to the hydraulic tank. At the time of page 11, the hydraulic motor 11 rotates to the hoisting side, and the rotational force is transmitted to the hoisting drum 13, and the suspended load 1 is transferred via the hoisting lobe 18.
Wind up 9. When the hoisting lever 6' is returned to neutral, the pressure oil that was pushing the A side boat of the directional control valve 8 is transferred to the pilot valve 6.
6a and returns to the hydraulic tank, and the directional control valve 8 also returns to neutral. Therefore, the pressure oil from the hydraulic pump 2 returns to the hydraulic tank through the neutral boat of the directional control valve 8, so the hydraulic motor 11 is stopped. At this time, an external force (due to the hanging load 19) is applied to the hydraulic motor 11 to discharge oil to the A side, but the A side of the hydraulic motor 11 is diblocked by the variable throttle valve 12 and the counterbalance valve 9. Therefore, the suspended load 19 is hydraulically locked (by the holding pressure), and the hydraulic motor 11 and drum 13 can hold the suspended load 19 without rotating toward the lower side. At this time, the switching valve 15 has been switched to the D port. Next, when the hoisting lever 6' is moved to the lower hoisting side (B side), the pressure oil from the hydraulic pump 3 passes through the lowering boat 6b of the pilot valve 6 to the control section on the B boat side of the directional control valve 8. As a result, the directional control valve 8 is switched to the B boat. The three-way switching valve 15 is also switched to the C boat. However, since the brake pedal 14 is depressed, the variable throttle 9 valve 12 is fully closed and the connection between X and Y remains cut off, and the switching valve 15 is actually There is no change. When the direction switching valve 8 is switched to the B boat, the pressure oil of the hydraulic pump 2 flows in the direction of the dotted line arrow, enters the B side of the hydraulic motor 11, passes through the A side of the hydraulic motor 11, and reaches the counterbalance valve 9. In the counterbalance valve 9, since both the pressure regulating valve 9b and the check valve 9C are blocked, the pressure on the B side of the hydraulic motor 11 increases, and the pi-cut pressure opens the pressure regulating valve 9b, and the pressure oil flows through the pressure regulating valve 9b and the direction. It passes through the switching valve 8 and returns to the tank. At this time, the pressure regulating valve 9b establishes back pressure on the A side of the hydraulic motor 11 according to the load of the suspended load 19, and prevents the suspended load 19 from escaping. The above is the operation during negative braking. At this time, the hydraulic motor 11 rotates at a speed that matches the flow rate of the hydraulic pump 2, and the suspended load 1
Roll up 9 and lower 1 roll. Further, when the hydraulic motor 11 is stopped, the suspended load 19 is held.

Next, the operation during positive braking will be explained.

-13--.

Positive brakes are mainly used when crawler cranes are used as excavators for clamshells, draglines, etc. When the hoisting lever 6' is placed on the hoisting side a, the hoisting drum 1
3 rotates to the hoisting side to hoist the suspended load 19, and the hoisting lever 6
'Holding and lowering of the suspended load 19 in the neutral state is performed by operating the brake pedal 14. In addition, the winding lever 6'
Power lowering is also possible by placing it in the lower side tray. Since the power hoisting and power hoisting are the same as the operations during negative braking, a description will be given of the case where the suspended load 19 is caused to free fall and is braked using the brake pedal 14. Hanging load 19
Free fall is possible when the hoisting lever 6' is in the neutral position, and at this time the switching valve 15 is in the D position. In this state, when the foot pressure on the brake pedal 14 is released, the variable throttle valve 12 is fully opened by the spring force. At this time, since a load is applied to the hoisting drum 13 in the lowering direction (because the load 19 is suspended), the hydraulic motor 11 acts as a pump and discharges pressure oil in the input direction. The pressure oil passes through the D boat of the switching valve 15 (flows in the direction of the dashed-dotted line arrow)
, passes through the variable throttle valve 12, and enters the hydraulic motor 11 again from the B side of the hydraulic motor 11.

That is, the hoisting drum 13 is rotated by an external force, and the pressure oil circuits from the hydraulic motor IIA boat to the switching valve 15 D boat to the variable throttle valve 12 to the hydraulic motor IIB boat.

At this time, oil leaked due to leakage of the hydraulic motor 11 or the like is replenished to the B side of the hydraulic motor 11 via the check valve 10 by the boost hydraulic pump l.

This prevents cavitation and prevents the hydraulic brake from becoming ineffective due to air intrusion. When braking the free-falling suspended load 19, the brake pedal 14 is depressed. brake pedal 1
4, the opening area of the variable throttle valve 12 is small, and its passage resistance causes brake pressure to be built up on the A side of the hydraulic motor 11, thereby braking the hydraulic motor 11 and braking the suspended load 19. When the weight of the suspended load 19 is constant, the more strongly the brake 14 is depressed, the smaller the opening area of the variable throttle valve 12 becomes.
The free fall speed of can be reduced. The brake pressure at this time acts on the spring side of the variable throttle valve 12 (the opposite side to which the pedal force is applied) and reaches the brake pedal 14, so that the pedal force on the brake pedal 14 becomes heavier.

That is, when the heavy suspended load 19 is lowered by braking, the brake pressure of the hydraulic motor 11 increases, so the brake pedal 14
becomes heavy. As a result, the situation of the suspended load 19 (load weight, falling speed, etc.) is fed back to the foot that depresses the brake pedal 14, so that an appropriate brake operation can be performed. In addition, this variable throttle valve 12 performs pressure compensation and temperature compensation, so that regardless of the weight of the load, if the brake pedal stroke is the same, the passing flow rate will be the same (the free fall speed is the same), and the oil temperature will change. Even if the viscosity of the oil changes, it will not be affected because it is squeezed by the orifice.

In the above-described embodiment, a hydraulic winch for a crawler crane has been described, but the hydraulic circuit of the present invention can also be used for a hydraulic winch capable of seven leaf alls for other machines. In addition, hoisting up, hoisting down, and stopping and holding are simply suspended loads.
9 has been explained, but it goes without saying that JP-A-61-81392 (5) can also be used for clamshell and dragline excavators.

〔Effect of the invention〕

As is clear from the above embodiments, the hydraulic circuit of the hydraulic winch of the present invention includes a variable throttle valve provided in parallel between the hydraulic motor and the counterbalance valve, and a brake operating device linked to the variable throttle valve. In addition, a switching valve is connected to the pilot valve, and the switching valve is connected in series to the variable throttle valve, so freefall is possible by circuiting the hydraulic motor, variable throttle valve, and switching valve. Furthermore, the variable throttle valve can be actuated by operating the brake operating device to apply back pressure to the hydraulic motor and generate braking force. Therefore, there are negative brakes that apply hydraulic pressure when the hoist lever is in the neutral position without using a mechanical latch device, brake device, or clutch and brake control device, and positive brakes that allow free fall and manual brake operation when the hoist lever is in the neutral position. brake and can be selected. In addition, a mechanical latch device, a brake device, and a clutch and brake control device are no longer required, resulting in an extremely simple structure. Furthermore, since the brake and clutch contact parts of the hoisting drum are no longer required,
Accordingly, the width of the drum can be increased, the winding capacity of the hoisting rope can be improved, and the durability of the rope can be extended. Furthermore, the degree of freedom when designing the winch is increased. Furthermore, parts such as conventional brake and clutch devices that require maintenance due to wear of the linings are no longer required, making it completely maintenance-free and preventing serious accidents such as dropped loads due to poor maintenance. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the hydraulic winch hydraulic circuit of the present invention. FIG. 2 is a side view of a crawler crane using the hydraulic winch hydraulic circuit of the present invention. 1... Hydraulic pump for boost, 2... Hydraulic pump for hydraulic motor drive, 3... Hydraulic pump for pilot, 6
...Pilot valve, 8...Directional switching valve, 9...Counterbalance valve, 11...Hydraulic motor, 12...
・Variable throttle 18 □ Valve, 13...Hoisting drum, 14...Brake pedal, 14'...Brake link, 15...Switching valve.

Claims (1)

[Claims] 1. A hydraulic power source and a pilot valve connected to the hydraulic power source;
A directional switching valve that is connected to a hydraulic power source and a pilot valve and switches the direction of pressure oil by operating the pilot valve, a counterbalance valve connected to the directional switching valve, and a counterbalance valve that is connected to the counterbalance valve to drive the hoisting drum. In the hydraulic circuit of a hydraulic winch equipped with a hydraulic motor, a variable throttle valve is provided in parallel between the hydraulic motor and the counterbalance valve, a brake operating device is linked to the variable throttle valve, and a switching valve is connected to the pilot valve. By connecting the switching valve in series with the variable throttle valve, you can select negative brake by locking the brake operating device, and positive braking by unlocking the brake operating device. A hydraulic circuit for a hydraulic winch characterized by comprising: 2. The hydraulic circuit for a hydraulic winch as set forth in claim 1, wherein the hydraulic circuit is configured to apply a boost to the suction port side of the hydraulic motor during free fall. 3. The brake pressure of the hydraulic motor during braking with the variable throttle valve is configured to be guided in a direction opposite to the operating direction of the brake operating device of the variable throttle valve. Hydraulic circuit of the hydraulic winch according to item 2.