JPS6251875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a constant horsepower type hydraulic winch control system.

In general, a constant horsepower hydraulic winch device maintains the supply flow rate and supply pressure constant from a hydraulic source equipped with a constant displacement hydraulic pump to a variable displacement hydraulic motor, and when the volume of the variable displacement hydraulic motor changes, the rotation speed and The output torque changes and a constant horsepower characteristic as shown in FIG. 2 is obtained.

The prior art of the present invention will be explained with reference to the drawings. In FIG. 1, a hydraulic power source 1 and a variable displacement hydraulic motor 2 (hereinafter simply referred to as the hydraulic motor) are connected through a flow path in which a directional control valve 3 and a counterbalance valve 4 are interposed to form a circulation circuit. The hydraulic pressure between the check valve 8 of the counterbalance valve 4 and the hydraulic motor 2 is selectively guided to the large chamber 6 and small chamber 7 of the volume increase/decrease mechanism 5 of No. 2 through a high pressure selection valve 9 and a constant horsepower control valve 10.

The constant horsepower control valve 10 has a piston 1 attached to one end of a spool 12 that is slidably inserted into a casing 11.
3, a spring 14 is disposed at the other end, and hydraulic pressure from a high pressure selection valve 9 is applied to the piston 13. At this time, when the spool pressing force of the piston 13 is equal to the setting force of the spring 14, the spool 12 is in the neutral position and blocks the large chamber 6 and the small chamber 7, and the spool pressing force of the piston 13 overcomes the force of the spring 14. Then, the spool 12 moves to the right and connects the primary port 15 and the large chamber port 16 and the tank port 17 and the small chamber port 18, and conversely, the force of the spring 14 is applied to the piston 1.
After overcoming the spool pressing force of 3, the spool 12
moves to the left and communicates the primary port 15 with the small chamber port 18 and the tank port 17 with the large chamber port 16. Note that the tank port 17 communicates with the tank side via a return flow path 19.

In this conventional device, in order to hoist a load, the directional control valve 3 is switched from the neutral position to the position A, and the pump working fluid from the hydraulic source 1 is transferred to the counterbalance valve 4.
As shown in FIG. 3, part of the hydraulic fluid enters the primary port 15 of the constant horsepower control valve 10 from the high pressure selection valve 9, and the fluid pressure is applied to the piston. 13. At that time, the spool pressing force by the piston 13 and the spring 1
When the setting forces 4 are balanced, the spool 12 is located at the neutral position as shown in the figure, blocking the large chamber 6 and the small chamber 7, and the hydraulic motor 2 exhibits constant horsepower characteristics. Here, when the pressure acting on the piston 13 decreases due to a change in load, the spool 12 is moved to the left by the spring 14, and as shown in FIG. 16 communicate with each other, hydraulic fluid flows into the small chamber 7, and the volume of the hydraulic motor 2 decreases. In this case, the pressure increases as the volume of the hydraulic motor decreases, and when this pressure reaches a reference pressure at which the spool pressing force of the piston 13 and the setting force of the spring 14 become equal, the spool 1
2 returns to the neutral position where the large chamber 6 and small chamber 7 are blocked (Fig. 3), resulting in constant horsepower control. The capacity of the hydraulic motor 2 at this time is smaller than that at the previous spool neutral position. Then, when the hydraulic pressure acting on the piston 13 increases due to a change in load, the spool 12 moves to the right against the spring 14, and the primary port 15
The large chamber port 16, the tank port 17, and the small chamber port 18 are communicated with each other, the hydraulic fluid flows into the large chamber 6, and the capacity of the hydraulic motor 2 increases. As a result, the pressure decreases and when it reaches the reference pressure, the spool 12 returns to the neutral position. The capacity of the hydraulic motor 2 at this time is larger than that at the previous spool neutral position.

That is, when hoisting a load, as shown in Figure 2, when the load becomes heavy, the volume of the hydraulic motor increases and the hoisting speed decreases, and when the load becomes light, the volume of the hydraulic motor decreases and the hoisting speed increases. Become.

Next, move the directional control valve 3 to position B to lower the load.
When the pump operating fluid is guided to the hydraulic motor 2 through the flow path 20, as shown in FIG.
When the discharge fluid passes through the counterbalance valve 4, a control pressure is generated upstream of the check valve 8 of the counterbalance valve 4, and since this pressure is higher than the motor inlet pressure, it acts on the piston 13 through the high pressure selection valve 9. do. In this case, when the spool pressing force of the piston 13 and the force of the spring 14 are balanced, the large chamber 6 and the small chamber 7 are blocked by the spool 12. Also, when the spool pressing force of the piston 13 overcomes the force of the spring 14 due to a change in load, the spool 12 moves to the right and the large chamber 6
The hydraulic fluid flows into the hydraulic motor 2, increasing the volume of the hydraulic motor 2.
Lowering speed decreases. Conversely, when the spool pressing force of the piston 13 becomes lower than the force of the spring 14 due to a change in load, the spool 12 moves to the left and the small chamber 7
The hydraulic fluid flows into the hydraulic motor 2 and the volume of the hydraulic motor 2 decreases.
The lowering speed increases. Therefore, the lowering speed is the second
As shown in the figure, the speed corresponds to the load, similar to when hoisting cargo. For this reason, when unloading cargo, high speed can only be achieved with light loads, resulting in a significant drop in work efficiency.

Next, when the load is suspended in the air, the braking pressure generated by the counterbalance valve 4 acts on the piston 13 of the constant horsepower control valve 10, as shown in FIG. Similarly to time, the volume of the hydraulic motor 2 changes depending on the load. Therefore, when the volume of the hydraulic motor is small, the amount of sag (the amount of load shedding), which is inversely proportional to the square of the volume of the hydraulic motor, increases.

To explain this, the sag amount is ΔN, the load is P,
Letting the volume of the hydraulic motor be q and the amount of oil leaking from the hydraulic motor etc. be ΔQ, the following relational expression can be obtained.

ΔQ∝P...(1) ΔN=ΔQ/q...(2) The output torque T of the hydraulic motor is T=P・q/2π...(3) When the load is constant, the output torque T is constant. ,
From equation (3), P∝1/q...(4) ∴ΔN=ΔQ/q∝P/q∝1/q ² ...(5) In other words, the sag amount ΔN is the square of the volume q of the hydraulic motor. Since it is inversely proportional to , if the volume of the hydraulic motor is small when suspending a load, the amount of sag will be large, making the work dangerous.

In view of the above-mentioned points, the present invention has a relatively simple configuration, and when hoisting a load, the speed corresponds to the load, and when the load is suspended, the volume of the hydraulic motor is kept at the maximum, thereby reducing the amount of sag, thereby making cargo handling work safer. The purpose of this invention is to improve the efficiency of cargo handling operations by keeping the volume of the hydraulic motor to a minimum regardless of the weight of the load during cargo unloading, and by lowering the cargo at high speed.

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 7, a hydraulic source 1 equipped with a constant displacement hydraulic pump and a variable displacement hydraulic motor 2 (hereinafter referred to as hydraulic motor) are connected to flow paths 21, 22, 23 with a direction control valve 3 and a counterbalance valve 4 interposed therebetween. , 24 to form a circulation circuit, and the passages 22 and 24 on both sides of the hydraulic motor 2 are connected to a high pressure selection valve 27 through passages 25 and 26, and the hydraulic fluid from this high pressure selection valve 27 is controlled by constant horsepower. The valve 28 selectively guides the hydraulic motor 2 to a large chamber 30 and a small chamber 31 of the volume increase/decrease mechanism 29 . The above configuration is substantially the same as the conventional device shown in FIG. However, in this embodiment, the structure of the constant horsepower control valve 28 is different from that of the conventional device;
A hydraulic switching valve 32 for controlling the constant horsepower control valve 28 and a sequence valve 33 for switching the hydraulic switching valve are provided.

The constant horsepower control valve 28 has one end of a spool 35 slidably fitted into the casing 34 abutting a small diameter piston 37 fitted into the liquid chamber 36, a spring 38 at the other end, and a small diameter piston 37 fitted into the liquid chamber 39 at the other end. A large-diameter piston 40 is installed to set the spring 38 to a predetermined spring force at the stroke end of the spool side, and when the spool 35 moves to the left from the neutral position shown in the figure, the primary port 41, the small chamber port 42, and the tank port 43 are connected to each other. Chamber port 4
4 communicate with each other, and when the spool 35 moves to the right from the neutral position shown in the figure, the primary port 41 and the large chamber port 44 and the tank port 43 and the small chamber port 42 communicate with each other.

A passage 46 connecting the secondary port 45 of the high pressure selection valve 27 and the primary port 41 of the constant horsepower control valve 28 is connected to the sequence valve 3 which takes the hydraulic pressure here as the pilot pressure.
3 through a branch passage 47, and this sequence valve 3
3 is in position A under normal conditions, that is, except when lowering an excessive load, blocking the branch passage 47 and communicating the passage 48 branched from the flow passage 26 with the pilot passage 49 of the hydraulic switching valve 32; The holding circuit 50 is communicated with a return flow path 51. In addition, when lowering an excessive load, in position B, the branch passage 47 is connected to the holding circuit 50, the passage 48 is blocked, and the pilot passage 49 of the hydraulic switching valve 32 is connected to the holding circuit 50.
is communicated with the return passage 51.

The hydraulic switching valve 32 connects a passage 52 branched from the passage 46 and a passage 53 branched from the passage between the directional control valve 3 and the counterbalance valve 4 to the constant horsepower control valve 2.
The liquid chambers 36 and 39 of No. 8 are selectively connected to each other. When unloading a load, the pump is switched to position B by the hydraulic pressure of the pump led to the pilot passage 49, and the passage 52
The liquid pressure is led to the liquid chamber 39, and the liquid chamber 36 is led to the tank via the directional control valve 3.

Since the present embodiment has the above-mentioned configuration, in FIG.
2. When guided to the hydraulic motor 2 via the check valve 8,
A part of the pump working fluid passes through the high pressure selection valve 27 and reaches the primary port 41 of the constant horsepower control valve 28. On the other hand, the hydraulic switching valve 32 is in position A because the pilot passage 49 communicates with the tank side. High pressure selection valve 27
The fluid pressure from the constant horsepower control valve 28 is transferred to one of the fluid chambers 36
and guides the hydraulic pressure in the passage 53 to the other liquid chamber 39. As a result, the large diameter piston 40 is positioned at the left stroke end and the spring 38 is set to a predetermined set pressure. In this case, when the force of the spring 38 and the spool pressing force of the small diameter piston 37 are balanced, the spool 35 is moved to the neutral position. The large chamber 30 and the small chamber 31 are blocked by the hydraulic motor 2, and the hydraulic motor 2 exhibits constant horsepower characteristics. Here, when the load becomes heavy and the pressure acting on the small diameter piston 37 becomes high, and the spool pressing force overcomes the force of the spring 38, the spool 35 moves to the right and moves toward the primary port 41.
The large chamber port 44 and the tank port 43 are communicated with the small chamber port 42, and the hydraulic fluid flows into the large chamber 30, increasing the capacity of the hydraulic motor 2. In this case, the pressure decreases as the volume of the hydraulic motor increases, and when this pressure decreases to a reference pressure at which the spool pressing force of the small diameter piston 37 and the setting force of the spring 38 are equal, the spool 35 is moved between the large chamber 30 and the small chamber 31. The engine returns to the neutral position where the engine is blocked, and constant horsepower control is established. The capacity of the hydraulic motor 2 at this time is larger than that at the previous spool neutral position. Then, when the load becomes lighter and the pressure acting on the small-diameter piston 37 decreases, the spool 35 moves to the left by the spring 38 to connect the primary port 41 and the small chamber port 42 and the tank port 43 and the large chamber port 44, and is activated. Liquid is in small chamber 3
1 and the volume of the hydraulic motor decreases. As a result, the pressure increases and when it reaches the reference pressure, the spool 35 returns to the neutral position and blocks the large chamber 30 and small chamber 31. The capacity of the hydraulic motor 2 at this time is smaller than that at the previous spool neutral position.

That is, when hoisting a load, as shown in Figure 8, when the load becomes heavy, the volume of the hydraulic motor increases and the hoisting speed decreases, and when the load becomes light, the volume of the hydraulic motor decreases and the hoisting speed increases. Become.

When the load is suspended in the air, as shown in FIG. 10, the braking pressure generated by the counterbalance valve 4 acts on the small diameter piston 37 of the constant horsepower control valve 28 via the high pressure selection valve 27 and the hydraulic switching valve 32. On the other hand, the liquid chamber 39 is connected to the hydraulic switching valve 32 and the passage 5.
3. It communicates with the tank through the flow path 22, the directional control valve 3, and the flow path 23, and the spring 38 presses the large diameter piston 40 toward the right stroke end, reducing the spring force, so the spool 35 moves toward the right stroke end. At this time, the primary port 41 and the large chamber port 44 and the tank port 43 and the small chamber port 42 are communicated with each other, and the capacity of the hydraulic motor 2 is maximized. Therefore, the amount of slip rotation due to leakage of the hydraulic motor, etc. is reduced, and the amount of sag can be minimized.

Next, move the directional control valve 3 to position B to lower the load.
When the pump hydraulic fluid is guided to the hydraulic motor 2 through the flow paths 21 and 24, the pump fluid pressure is changed to the flow path 26, the passage 48, and the sequence valve 3, as shown in FIG.
3. Since the hydraulic switching valve 32 is switched to position B via the pilot passage 49, the liquid chamber 36 of the constant horsepower control valve 28 is transferred via the hydraulic switching valve 32, the passage 53, the flow path 22, the directional control valve 3, and the flow path 23. On the other hand, when the discharged fluid from the hydraulic motor 2 passes through the counterbalance valve 4, the braking pressure generated upstream of the check valve 8 is led to the fluid chamber 39 via the high pressure selection valve 27 and the hydraulic switching valve 32, and the large Since the diameter piston 40 is positioned at the left stroke end, the spool 35 is at the left stroke end and communicates between the primary port 41 and the small chamber port 42, and between the tank port 43 and the large chamber port 44, regardless of the weight or weight of the load. Therefore, the capacity of the hydraulic motor 2 is minimized, and as shown in FIG. 8, the maximum load unloading speed is obtained regardless of the weight or weight of the load, improving work efficiency.

Furthermore, when switching the directional control valve 3 to position B to lower an excessive load, the discharged fluid from the hydraulic motor 2 is transferred to the counterbalance valve 4 as shown in FIG.
The braking pressure generated upstream of the check valve 8 when passing through is led to the passage 46 via the high pressure selection valve 27, and switches the sequence valve 33 to position B, which is where the fluid from the passage 47 led to the holding circuit 50 is transferred. By being held under pressure, the pilot passage 49 of the hydraulic switching valve 32 communicates with the tank side via the return passage 51. As a result, the hydraulic switching valve 32 is switched to position A, the pressure from the high pressure selection valve 27 acts on the small diameter piston 37 of the constant horsepower control valve 28, and the liquid chamber 39 is connected to the hydraulic switching valve 32, the passage 53, and the flow path 22. , the directional control valve 3, and the flow path 23 to the tank, and the spring 38 is expanded and the spring force is reduced, so the spool 35 is located at the right stroke end, and the primary port 41 and the large chamber port 4 are connected to each other.
4 and the tank port 43 and the small chamber port 42 are communicated with each other. Therefore, the hydraulic fluid flows into the large chamber 30, the volume of the hydraulic motor 2 becomes maximum, the pressure decreases, and the unloading speed becomes the minimum speed, so that cargo handling work can be carried out safely.

As explained above, according to the present invention, by the combination of the constant horsepower control valve that controls the volume increase/decrease mechanism of the variable displacement hydraulic motor and the hydraulic switching valve that switches to the constant horsepower control valve,
Since the hoisting speed corresponding to the load during cargo hoisting is obtained and the capacity of the hydraulic motor is maximized when the cargo is suspended, the amount of sag is reduced and cargo handling work can be carried out safely. Furthermore, since the volume of the hydraulic motor is kept at a minimum regardless of the weight or weight of the load during unloading, high-speed unloading is possible regardless of the weight or weight of the load, improving work efficiency.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram of a conventional device, Fig. 2 is a chart showing the relationship between load (hydraulic motor capacity) and cargo hoisting/unloading speed in the conventional device, Figs.
Fig. 6 is an explanatory diagram of the operation of the conventional device, Fig. 3 is a hydraulic circuit diagram during constant horsepower control during cargo hoisting, and Fig. 4 is an explanatory diagram of the operation of the conventional device.
The figure is a hydraulic circuit diagram for hoisting a load, Figure 5 is a hydraulic circuit diagram for constant horsepower control when lowering a load, Figure 6 is a hydraulic circuit diagram for suspending a load, and Figure 7 is an example of the present invention. 8 is a diagram showing the relationship between the load and the load hoisting/lowering speed in the device of the present invention. FIGS. 9 to 12 are diagrams explaining the operation of this embodiment. Hydraulic circuit diagram during constant horsepower control during hoisting, Fig. 10 is a hydraulic circuit diagram when a load is suspended, Fig. 11 is a hydraulic circuit diagram when lowering a load, Fig. 12
The figure is a hydraulic circuit diagram when lowering an excessive load. 1... Hydraulic source, 2... Variable displacement hydraulic motor, 3...
Direction control valve, 4...Counter balance valve, 8...Check valve, 27...High pressure selection valve, 28...Constant horsepower control valve, 29...Volume increase/decrease mechanism, 30...Large chamber, 31...Small chamber, 32...Hydraulic pressure switching valve, 33 ...Sequence valve, 3
5...Spool, 37...Small diameter piston, 38...Spring, 40...Large diameter piston.

Claims (1)

[Claims] 1 A circulation circuit is constructed by connecting a variable displacement hydraulic motor connected to a winch drum and a hydraulic power source through a flow path equipped with a direction control valve and a counterbalance valve,
In a constant horsepower control valve that selectively guides hydraulic pressure to the large chamber and small chamber of the volume increase/decrease mechanism of the variable displacement hydraulic motor to change the volume of the variable displacement hydraulic motor, the constant horsepower control valve A small-diameter piston is provided at one end of the spool, and a large-diameter piston that presses the spring and sets a predetermined spring force is provided at the other end of the spool. A hydraulic switching valve is provided that selectively guides the pressure before and after the check valve, and this hydraulic switching valve transfers the hydraulic pressure on the variable displacement hydraulic motor side of the check valve to the large diameter piston when unloading the load. The hydraulic pressure on the side of the directional control valve of the check valve is guided to the small diameter piston, and the hydraulic pressure on the variable displacement hydraulic motor of the check valve is directed to the small diameter piston, and the hydraulic pressure on the directional control valve of the check valve is increased when hoisting a load or suspending the load. A constant horsepower type hydraulic winch control device characterized by being guided to a diameter piston.