JP2002012392A - Winch control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the surge pressure while ensuring the motor speed range. SOLUTION: The relationship A1 between the rope line pull T and the drum rotational speed w for keeping the surge pressure when a motor is suddenly stopped so as not to exceed the allowable value is stored in a controller 14 in advance. A load detector 10 for detecting the rope line pull T is provided on a sheave 49, the drive of an electromagnetic proportional valve 13 is controlled according to the detected value T of the rope line pull, and the capacity of a hydraulic pump 1 is continuously controlled so that the relationship between the rope line pull T and the drum rotational speed w when the engine speed is maximum and the lever operation is maximum is agreed with the stored characteristic A1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winch control device for reducing a surge pressure generated in a hydraulic circuit when the winch is stopped.

[0002]

2. Description of the Related Art Today, there is an increasing demand for driving a winch at a high speed for reasons such as improving work efficiency. However, when the winch is driven at a high speed, an excessive surge pressure is generated at the time of a sudden stop, which adversely affects a hydraulic motor and the like. In order to solve such a problem, a device designed to reduce the surge pressure when the winch is stopped is disclosed in, for example, Japanese Patent No. 287.
No. 5185. In the device described in this publication, the actual load acting as the sum of the load of the suspended load and the impact load expected to be generated when the suspended load is suddenly stopped at the hoisting or lowering speed at that time. Is calculated, and when the actual load is smaller than a predetermined allowable value, the displacement of the hydraulic motor is switched to the small capacity side, and when the actual load is equal to or more than the allowable value, the displacement is switched to the large capacity side. This limits the motor speed when a high load acts on the hydraulic motor, and suppresses the surge pressure when the winch stops.

[0003]

However, in the device described in the above-mentioned publication, the displacement of the motor is switched to either the large-capacity side or the small-capacity side in accordance with the actual applied load, so that the following problem occurs. . In other words, the same motor displacement is used when the actual applied load slightly exceeds the allowable value and when the actual applied load greatly exceeds the allowable value. In this case, the speed of the motor is limited, the motor speed range is narrowed, and the workability deteriorates. In addition, the displacement of the motor is switched to the large-capacity side or the small-capacity side at the boundary of the allowable value, so that the behavior of the suspended load suddenly changes depending on whether the actual applied load is slightly smaller than the allowable value or slightly larger than the allowable value. And it becomes difficult for the operator to handle.

[0004] It is an object of the present invention to provide a winch control device capable of securing a motor speed range, smoothing the behavior of a suspended load, and reducing a surge pressure when the winch is stopped. .

[0005]

A description will be given with reference to the drawings showing an embodiment. (1) As shown in FIG. 1, the invention of claim 1 is driven in accordance with the operation of a hydraulic pump 1, a hydraulic motor 2 rotated by pressure oil discharged from the hydraulic pump 1, and an operation lever 5. And a control valve 3 for controlling the flow of pressurized oil from the hydraulic pump 1 to the hydraulic motor 2. And a load detecting means 10 for detecting a physical quantity T having a correlation with the load acting on the hydraulic motor 2.
And rotation speed limiting means 1a, 13 for limiting the maximum rotation speed w of the hydraulic motor 2, and at least at the time of the lowering operation of the operation lever 5, according to the detection result from the load detection means 10, the lower the higher the load, the lower the maximum. The above-mentioned object is achieved by providing the control means 14 for controlling the rotation speed limiting means 1a, 13 so as to obtain the rotation speed. (2) According to a second aspect of the present invention, in the winch control device according to the first aspect, the control means 14 stores a detection result by the load detection means 10 before the operation lever 5 is lowered. Based on the stored value T0, the rotation speed limiting means 1a,
13 is controlled. (3) The winch control device according to claim 1 or 2, wherein the control means (14) controls the hoisting operation in which the limit value w2 of the maximum number of revolutions during the hoisting operation is determined by horsepower control. The rotation speed limiting means 1a and 13 are controlled so as to be substantially equal to the maximum rotation speed w1 at the time. (4) According to a fourth aspect of the present invention, in the winch control device according to any one of the first to third aspects, the rotation speed limiting means includes pump displacement control devices 1a and 13 for controlling the displacement of the hydraulic pump 1. And the control means 14 controls the load detection means 10
Pump capacity control devices 1a, 1 according to the detection result T from
3 is controlled. (5) According to a fifth aspect of the present invention, in the winch control device according to any one of the first to third aspects, as shown in FIG. Control means 20a, 19,
4 controls the motor displacement control devices 20a and 19 according to the detection result T from the load detection means 10. (6) According to a sixth aspect of the present invention, in the winch control apparatus according to any one of the first to third aspects, as shown in FIG. It has a valve control device 18, and the control means 14 controls the control valve control device 18 according to the detection result from the load detection means 10. (7) The winch control device according to claim 6, wherein the control means controls the differential pressure ΔP across the control valve 3 to be substantially constant irrespective of the load of the hydraulic motor 2. The control valve control device 18 is controlled. (8) According to an eighth aspect of the present invention, in the winch control device according to any one of the first to seventh aspects, as shown in FIG. 9, the holding pressure P1 of the hydraulic motor 2 is a physical quantity. (9) According to a ninth aspect of the present invention, in the winch control device according to any one of the first to seventh aspects, as shown in FIG. 12, the hoisting driving pressure P3 of the hydraulic motor 2 is a physical quantity. . (10) According to a tenth aspect of the present invention, in the winch control device according to any one of the first to ninth aspects, as shown in FIG. The means 14 controls the rotation speed limiting means 1a and 13 according to the winding layer N detected by the winding layer detecting means 21. (11) According to an eleventh aspect of the present invention, in the winch control device according to any one of the first to tenth aspects, as shown in FIG. When the load exceeds a predetermined value Tc, the rotation speed limiting means 1a and 13 are controlled so that the maximum rotation speed becomes a predetermined lower limit wc.

DETAILED DESCRIPTION OF THE INVENTION

[0006] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a hydraulic circuit diagram showing a configuration of a winch control device according to a first embodiment of the present invention, and FIG. 4 is a side view of a crane having the control device. It is. As shown in FIG. 4, the crane includes a traveling body 41 and a revolving body 43 rotatably mounted on the traveling body 41 via a revolving device 42.
And a boom 44 attached to the tip of the revolving structure 43 so as to be able to undulate, by driving a hoisting drum 46 of a winch around which a hoisting rope 45 is wound, to drive up or down.
A suspended load 48 suspended via a hook 47 is moved up and down via a sheave 49 at the end of the boom.

As shown in FIG. 1, a winch control device according to the present embodiment includes a variable displacement hydraulic pump 1 driven by an engine, and a hydraulic motor driven by hydraulic oil discharged from the hydraulic pump 1. 2 and hydraulic pump 1
Control valve 3 for controlling the flow of pressure oil supplied from the hydraulic motor 2 to the hydraulic motor 2, a hoisting drum 46 driven to hoist and lower by the driving torque from the hydraulic motor 2, Lever 5 for inputting a command, and pilot valves 6A and 6B driven by the operation lever 5.
A pilot pressure source 7 for supplying pressure oil to the pilot valves 6A and 6B, a counter balance valve 8 for generating a holding pressure in the holding line L1, a load detector 10 for detecting a load acting on the sheave 49, Pressure sensors 11A and 11B for detecting the presence / absence of a lifting / lowering command from the operation lever 5, a hydraulic pump 12 for supplying a command pressure ps to a regulator 1a of the variable pump 1, and a
a proportional solenoid valve 13 for controlling the flow of pressure oil supplied to
And a controller 14 for controlling the drive of the electromagnetic proportional valve 13
And The capacity qp of the hydraulic pump 1 can be changed by the regulator 1a in the range of qpmin ≦ qp ≦ qpmax, and horsepower is controlled so that the pump output does not exceed the engine output.

The load detector 10 is, for example, a pin type load cell. The load detector 10 detects a line pull T of the hoisting rope 45. The line pull T has a correlation with the load acting on the hydraulic motor. In the controller 14, the signal from the load detector 10 and the pressure sensor 11
A, performs predetermined processing based on the signal from 11B,
The control signal is output to the solenoid of the electromagnetic proportional valve 13. As a result, the pressure from the hydraulic pump 12 is reduced to the command pressure ps according to the control signal, the pump displacement qp is controlled as described later, and the maximum speed of the hydraulic motor 2 is limited.

When the lowering drive of the drum 46 is suddenly stopped, a surge pressure is generated in the holding pipeline L1 as described later. The magnitude of the surge pressure depends on the inertia force of the suspended load 48 and the like. Therefore, in order to suppress the surge pressure at the time of the sudden stop of the lowering to be equal to or less than the allowable value determined from the pressure resistance of the motor 2 or the like, the lowering speed is reduced with an increase in the lifting load, and the inertial force may be limited. . Therefore, in the first embodiment, as a characteristic of making the surge pressure at the time of the emergency stop under the unwinding sudden stop equal to or less than the allowable value, the maximum speed of the drum 46 decreases as the rope line pull T increases as shown in FIG. Such a characteristic A1 is stored in the controller 14 in advance. And
The rotation speed of the drum 46 at the time of lowering is always equal to or lower than the characteristic A1, that is, the rotation speed of the drum 46 when the engine speed is maximum and the operation lever 5 is operated to the maximum (hereinafter, the maximum drum speed). Speed w) is characteristic A
By controlling the pump displacement qp to be equal to 1, the surge pressure at the time of the sudden stop of the motor is suppressed to an allowable value or less. In addition,
This characteristic A1 is obtained by an experiment, a simulation, or the like. FIG. 2 also shows the characteristic A0 when the maximum command pressure psmax acts on the regulator 1a. Characteristic A0
As shown in (1), since the pump 1 is controlled by horsepower, when the load exceeds a predetermined value, the pump capacity qp decreases according to the characteristic A0, and the drum maximum speed w is limited.

Here, using the flowchart of FIG.
An example of a process executed by the controller 13 will be described.
As shown in FIG. 3, first, in step S1, the pressure sensor 1
The signals from 1A and 11B are read, and then, in step S2, it is determined whether or not a winding operation is performed based on the signal from pressure sensor 11A. If it is determined in step S2 that the operation is not a hoisting operation, step S2 is denied and the process proceeds to step S3, where it is determined whether or not a hoisting operation is performed based on a signal from the pressure sensor 11B. If it is determined in step S3 that the operation is the lowering operation, step S3 is affirmed and the process proceeds to step S4, where the signal from the load detector 10, that is, the detected value T of the rope line pull is read.

Next, in step S5, the detected value T of the rope line pull is determined by using the preset characteristic A1 of FIG.
Is calculated (the unit is rpm). Subsequently, the process proceeds to step S6, and the target pump displacement qpa is calculated from the calculated value w by the following equation (I). qpa = w * I * qm / np (I) where I: reduction ratio between the drums 46 of the motor 2 qm: capacity of the motor 2 np: number of revolutions of the pump 1 Then, in step S7, the target is obtained from the characteristic data of the pump 1. The command pressure ps to the regulator 1a corresponding to the pump capacity qpa is calculated. Subsequently, in step S8, the degree of pressure reduction of the electromagnetic proportional valve 13 for generating the command pressure ps is calculated, and a control signal to the electromagnetic proportional valve 13 for setting the degree of pressure reduction is calculated. Next, in step S9, the control signal is output to the solenoid of the electromagnetic proportional valve 13, and in step S1
Return to As a result, the upper limit of the rotation speed of the drum 46 is controlled as shown by the characteristic A1 in FIG.

On the other hand, if it is determined in step S2 that the operation is a hoisting operation, step S2 is affirmed and the process proceeds to step S10.
The target pump displacement qpa is set to the maximum value qpmax. Next, in steps S7 to S9, a control signal for setting the pump 1 to the maximum capacity qpmax is calculated, and the electromagnetic proportional valve 13 is operated.
Output to the solenoid. Thus, the rotation speed of the drum 46 is controlled according to the characteristic A0 in FIG. Also,
If it is determined in step S3 that the operation lever is neutral, step S3 is denied and the routine proceeds to step S11, where the target pump displacement qpa is set to the minimum value qpmin. Next, in steps S7 to S9, a control signal for setting the pump 1 to the minimum displacement qpmin is calculated and output to the solenoid of the electromagnetic proportional valve 13. Thus, the rotation speed of the drum 46 is always controlled to the minimum.

Next, the operation of the first embodiment of the present invention will be described more specifically. In the hydraulic circuit shown in FIG. 1, when the operating lever 5 is hoisted, the pilot valve 6A is driven in accordance with the operation amount, and the hydraulic oil from the pilot hydraulic source 7 is supplied to the pilot valve of the direction control valve 3 via the pilot valve 6A. Supplied to port. As a result, the direction control valve 3 is switched to the position (A) according to the operation amount of the operation lever 5, and the pressure oil from the hydraulic pump 1 passes through the direction control valve 3, the counter balance valve 8, and the holding line L1. And supplied to the hydraulic motor 2. When the pressure in the holding line L1 reaches a predetermined holding pressure defined by the hanging load, the hydraulic motor 2 rotates in the hoisting direction, the drum 4 is driven to hoist, and the suspended load 48 rises. . At this time, the hoisting operation is detected by the pressure sensor 11A, and the pump displacement is set to the maximum qpmax by the processing of step S10 → step S7 to step S9 described above. Therefore, at the time of hoisting, the pump capacity is maximized, and the shortage of torque of the hoisting winch is eliminated.

On the other hand, when the operating lever 5 is lowered, the pilot valve 6B is driven in accordance with the amount of operation, and hydraulic oil from the pilot hydraulic source 7 is sent to the pilot port of the direction control valve 3 via the pilot valve 6B. Supplied. As a result, the direction control valve 3 is switched to the position (B) according to the operation amount of the operation lever 5, and the hydraulic oil from the hydraulic pump 1 is supplied to the hydraulic motor 2 via the direction control valve 3 and the lowering line L2. Supplied to Then, the counterbalance valve 8 is opened and closed according to the pilot pressure from inside the lowering line L2, and the holding line L
In the state where the pressure in 1 reaches the holding pressure, the holding line L1
Pressure oil flows out of the hydraulic motor 2
Rotates in the lower direction. As a result, the drum 4 is driven down and the suspended load 48 is lowered while maintaining the holding pressure.
At this time, the lowering operation is detected by the pressure sensor 11B, and the pump capacity qp is controlled in accordance with the rope line pull T by the processing of steps S4 to S9 described above. Therefore, even if the operation speed of the operation lever 5 is maximized while the engine speed is maximized, the rotation speed w
Does not exceed the characteristic A1 in FIG.

When the operation lever 5 is returned to the neutral position during the lowering drive of the drum 46, the pilot valve 6B also returns to the neutral position, and the pilot pressure oil acting on the pilot port of the direction control valve 3 is transmitted through the pilot valve 6B. Collected in tank. As a result, the direction control valve 3 is switched to the neutral position following the lever operation, the pressure in the lowering line L2 decreases, and the counter balance valve 8 is closed. As a result, the hydraulic brake force acts on the hydraulic motor 2, and the rotation of the hydraulic motor 2 stops immediately. At this time, drum 4
The hydraulic motor 2 is rotated by the inertia force in the lowering direction of 6, and the pressure in the holding pipeline L1 increases to a value corresponding to the inertia force (generation of surge pressure). However, as described above, since the drum maximum speed w is limited according to the rope line pull T, the inertia force of the drum 46 does not become excessive, and the surge pressure is suppressed to an allowable value or less.

When the operation lever 5 is returned to the neutral position, the pump displacement is set to the minimum qpmin by the processing of the above-described steps S11 → S7 to S9. Accordingly, even when the motor 2 rotates due to a malfunction of the direction control valve 3 when the operation lever 5 is in the neutral position, the rotation speed is minimized, so that the influence of the malfunction can be minimized. Although not shown, the drum 46 may be provided with a negative brake that operates when the operation lever 5 is neutral.

As described above, in the first embodiment, the pump capacity qp is controlled based on the rope line pull T having a correlation with the load acting on the hydraulic motor 2, and the maximum lowering speed w of the drum 46 is limited. Therefore, the surge pressure at the time of the lowering stop is reduced, the shock acting on the hydraulic device is reduced, and the durability of the device is improved. In this case, the pump capacity q
p is steplessly controlled, and the drum maximum speed w is reduced as the rope line pull T increases, as shown by the characteristic A1 in FIG. , And the behavior of the suspended load 48 becomes smooth with respect to the change of the rope line pull T.

-Second Embodiment- A second embodiment of the present invention will be described with reference to FIG.
The second embodiment differs from the first embodiment in the processing performed by the controller 14, and the configuration of the hydraulic circuit is the same as that in FIG. The difference is that the first embodiment detects the rope line pull as needed and controls the drum maximum speed w according to the detected value T.
In the second embodiment, the detected value T of the rope line pull is stored, and thereafter, the maximum drum speed is controlled based on the stored value Ta.

FIG. 5 is a flowchart showing an example of the processing in the controller 14 according to the second embodiment. The same portions as those in FIG. 3 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG.
When the target pump displacement qpa is set to the maximum qpmax or the minimum qpmin in step S10 or step S11, the process proceeds to step S21, where the signal from the load detector 10 is read to detect the rope line pull T. Then, step S
At 22, the detected value T is stored in the memory of the controller 14. This stored value Ta is updated each time the processing in step S22 is performed, and the latest value is stored in the memory. Next, the routine proceeds to step S5, where the drum maximum speed w corresponding to the stored value Ta is calculated using the characteristic A1 in FIG. As a result, the pump displacement qp is controlled based on the rope line pull T during the hoisting operation or when the operating lever is neutral,
During the lowering operation, the pump capacity qp is kept constant.

As described above, in the second embodiment, the drum maximum speed w is calculated based on the rope line pull T before the lowering operation, and during the lowering operation, the motor is adjusted to a value corresponding to the calculated value. The capacity qp was kept. As a result, even if the rope line pull T fluctuates at the time of starting the lowering operation, a stable system can be obtained without changing the pump capacity qp.

Third Embodiment A third embodiment of the present invention will be described with reference to FIGS. The third embodiment differs from the first embodiment in the processing performed by the controller 14, and the configuration of the hydraulic circuit is the same as that in FIG. As described above, the hydraulic pump 1
Is controlled by horsepower, so the pump capacity qp
The relationship between the rope line pull T and the drum maximum speed w when the operation lever 5 is operated to the maximum is as shown in FIG. 6, for example. In FIG. 6, the hoisting load acts in a direction that prevents the rotation of the motor 2 during hoisting, whereas the hoisting load acts in a direction that promotes the rotation of the motor 2 during hoisting. A larger load acts in comparison. As a result, the drum maximum speed w1 at the time of hoisting is smaller than the drum maximum speed w2 at the time of hoisting, and even when the same suspended load is hung, the inertia force at the time of hoisting is lower than at the time of hoisting. growing. Therefore, in the third embodiment, the maximum drum speed w2 during the lowering is changed to the maximum drum speed w1 during the lowering.
, Thereby reducing the surge pressure at the time of the lowering stop.

The characteristics at the time of hoisting shown in FIG.
Is stored. FIG. 7 is a flowchart illustrating an example of processing in the controller 14 according to the third embodiment. The same portions as those in FIG. 3 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG.
When the rope line pull T is detected in step S4, the process proceeds to step S23. In step S23, the drum maximum speed w corresponding to the detected value T of the rope line pull is calculated from the winding characteristic in FIG. 6, and the process proceeds to step S6. As a result, the drum 46 when the operation lever 5 is operated to the maximum
Is reduced to the hoisting speed w1.

As described above, in the third embodiment, the pump displacement qp is controlled steplessly, and the drum maximum speed w1 during lowering is controlled.
Is reduced to the maximum drum speed w2 at the time of winding, so that the inertia force of the drum 46 at the time of lowering is reduced, the surge pressure at the time of stopping the lowering is reduced, and the speed range of the drum 46 is greatly narrowed. Also, the behavior of the suspended load 48 with respect to the change of the rope line pull T is smooth. Drum 4
Since the hoisting speed w1 of No. 6 is matched with the hoisting speed w2, the hoisting speed and hoisting speed of the suspended load 48 when the operation lever 5 is operated to the maximum are the same, and the operability is improved.

In FIG. 7, the rope line is detected at any time, and the drum maximum speed w is controlled based on the detected value T. However, similar to the second embodiment, before the lowering operation is performed, The rope line pull T is stored and its stored value Ta
May be used to control the drum maximum speed w. An example of such a flowchart is shown in FIG. Thus, even when the rope line pull T fluctuates at the time of starting the lowering operation, a stable system can be obtained without changing the pump capacity qp.

-Fourth Embodiment- A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a hydraulic circuit diagram showing a configuration of a winch control device according to the fourth embodiment of the present invention. The same portions as those in FIG. 1 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 9, in the fourth embodiment, instead of the load detector 10, the holding conduit L
1, a pressure sensor 15 is provided, and the pressure sensor 15 detects the pressure p1 in the holding pipe line L1. In the controller 14, the signal from the pressure sensor 15 and the pressure sensor 11
A, performs predetermined processing based on the signal from 11B,
The control signal is output to the solenoid of the electromagnetic proportional valve 13.

The characteristic A3 in FIG. 10 shows the relationship between the holding pressure p1 and the drum maximum speed w for keeping the surge pressure at the time of the sudden stop of the motor below the allowable value. Since the holding pressure p1 has a correlation with the lifting load, the drum inertia force increases as the holding pressure p1 increases. Therefore, in order to reduce the surge pressure at the time of the sudden stop of the motor to the allowable value or less, it is necessary to decrease the drum maximum speed w with the increase of the holding pressure p1, as shown by the characteristic A3. Therefore, in the fourth embodiment, the maximum drum speed w is limited by the characteristic A3, thereby reducing the surge pressure at the time of the sudden stop of the motor. Note that the characteristic A3 is obtained by an experiment, a simulation, or the like, and is stored in the controller 14 in advance. FIG. 10 also shows the characteristic A4 (corresponding to the characteristic A0 in FIG. 2) when the maximum command pressure psmax acts on the regulator 1a.

FIG. 11 is a flowchart showing an example of the processing in the controller 14 according to the fourth embodiment. The same portions as those in FIG. 3 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 11, when it is determined that the lowering operation is performed in step S3, step S3 is performed.
Proceeding to 24, the pressure p1 in the holding pipe line L1 is detected based on the signal from the pressure sensor 15. Next, in step S25, a drum maximum speed w corresponding to the holding pressure p1 detected from the characteristic A3 in FIG. 10 is calculated, and the process proceeds to step S6. As a result, the drum maximum speed w at the time of lowering is controlled according to the holding pressure p1.

As described above, in the fourth embodiment, the pressure in the holding pipe line L1 is detected by the pressure sensor 15, and the drum rotation speed at the time of lowering is limited based on the detected value p1. It is not necessary to use a load detector such as a load cell, and the winch control device can be configured at low cost. Further, even when a plurality of winches are used at the same time, the speed of each winch can be independently limited.

Fifth Embodiment A fifth embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a hydraulic circuit diagram showing a configuration of a winch control device according to a fifth embodiment of the present invention.
The same parts as those in FIG. 9 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 12, in the fifth embodiment, not the holding line L1 but the hoisting line L3.
The pressure sensor 16 detects the pressure p3 in the hoisting line L3. Controller 1
4, the signal from the pressure sensor 16 and the pressure sensor 11A,
A predetermined process is executed based on the signal from 11B, and a control signal is output to the solenoid of the electromagnetic proportional valve 13.

A characteristic A5 in FIG. 13 shows the relationship between the hoisting drive pressure p3 and the drum maximum speed w for reducing the surge pressure at the time of the sudden stop of the motor to the allowable value or less. Hoisting drive pressure p
Since No. 3 has a correlation with the lifting load, the drum inertia force increases as the hoisting driving pressure p3 increases. Therefore, in order to reduce the surge pressure at the time of the sudden stop of the motor to the allowable value or less, it is necessary to decrease the drum maximum speed w with an increase in the hoisting drive pressure p5 as shown by the characteristic A5. Therefore, in the fifth embodiment, the drum maximum speed w is controlled in accordance with the characteristic A5, thereby reducing the surge pressure at the time of sudden stop of the motor. The characteristic A5 is obtained by an experiment or a simulation, and is stored in the controller 14 in advance. FIG. 13 also shows a characteristic A6 (corresponding to the characteristic A0 in FIG. 2) when the maximum command pressure psmax acts on the regulator 1a.

FIG. 14 is a flowchart showing an example of the processing in the controller 14 according to the fifth embodiment. The same parts as those in FIG.
Hereinafter, the differences will be mainly described. As shown in FIG. 14, when it is determined in step S2 that a hoisting operation is performed, step S2 is performed.
The program proceeds to 10, the target pump capacity qpa is set to the maximum value qpmax, and the program proceeds to step S26. In step S26, the signal from the pressure sensor 16 is read to detect the hoisting drive pressure p3. Then, in step S27, the hoisting drive pressure p3 is stored in the memory, and the flow advances to step S7. On the other hand, if it is determined in step S3 that the operation is the lowering operation, the process proceeds to step S28. In step S28, the drum maximum speed w corresponding to the pressure p3 stored immediately before the start of the lowering operation in step S27 is calculated from the characteristic A5 in FIG.
Proceed to 6. Thus, the pump displacement qp is controlled based on the hoisting driving pressure p3, and the pump displacement qp is kept constant during the hoisting operation.

As described above, in the fifth embodiment, since the maximum drum speed w during the lowering operation is limited based on the hoisting driving pressure p3, there is no need to provide a pressure sensor in the holding line L1. As a result, even when the pressure sensor 16 is broken, the predetermined holding pressure can be maintained without the pressure oil flowing out of the holding pipe line L1.

Sixth Embodiment A sixth embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a hydraulic circuit diagram showing a configuration of a winch control device according to the sixth embodiment of the present invention. The same portions as those in FIG. 1 are denoted by the same reference numerals, and the differences will be mainly described below. In the first embodiment, the pump displacement qp is controlled to limit the drum rotation speed w during the lowering. In the sixth embodiment, the pilot acting on the pilot port of the direction control valve 3 is controlled. The pressure pp is controlled to limit the drum rotation speed w during winding down.

As shown in FIG. 15, in the sixth embodiment, the hydraulic pump 17 for supplying the driving pressure oil to the motor 2 is of a fixed displacement type, and the pilot port on the lower side of the directional control valve 3 is connected to the pilot port. An electromagnetic proportional valve 18 is provided between the valve and the valve 6B. The controller 14 executes a predetermined process based on the signal from the load detector 10 and the signals from the pressure sensors 11A and 11B, and outputs a control signal to the solenoid of the electromagnetic proportional valve 18. As a result, the pressure oil from the lowering pilot valve 6B becomes equal to the pilot pressure p according to the control signal.
The pressure is reduced to p, and the maximum speed of the hydraulic motor 2 is limited during the lowering. Note that, in this case, the relationship between the rope line pull T and the drum maximum speed w for reducing the surge pressure at the time of the sudden lowering stop to the allowable value is the same as that shown in FIG.

FIG. 16 is a flowchart showing an example of the processing in the controller 14 according to the sixth embodiment. The same portions as those in FIG. 3 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 16, when the drum maximum speed w corresponding to the rope line pull T is calculated from the characteristic A1 in FIG. 2 in step S5, the process proceeds to step S31. In step S31, the target opening degree s of the directional control valve 3 required for flowing the pump discharge oil corresponding to the maximum drum speed w when the engine speed is below the maximum.
Calculate a. Next, in step S32, using the characteristic data of the directional control valve 3, a pilot pressure ppa for setting the opening of the directional control valve 3 to the target opening sa when the operation lever 5 is operated at the maximum is calculated. Subsequently, step S33
Then, a control signal to the electromagnetic proportional valve 18 required to generate the pilot pressure ppa is calculated, and the process proceeds to step S
At 34, the control signal is output to the solenoid of the electromagnetic proportional valve 18, and the process returns to step S1. Thereby, the drum 46
The upper limit of the rotation speed is limited according to the rope line pull T, and the surge pressure is suppressed to an allowable value or less.

On the other hand, if it is determined in step S2 that the operation is a hoisting operation, or if it is determined that the operation is not a hoisting operation in step S3, the process proceeds to step S35, where the target opening degree sa is set to the maximum opening degree smax. Proceed to. As a result, the valve opening of the electromagnetic proportional valve 18 is maximized, and the return oil from the pilot port of the directional control valve 3 during the lowering operation is collected in the tank without being blocked by the electromagnetic proportional valve 18 and the response oil is returned. The property becomes good.

As described above, in the sixth embodiment, the electromagnetic proportional valve 18 is provided between the pilot port of the directional control valve 3 and the pilot valve 6B, and the pilot to the directional control valve 3 is controlled according to the rope line pull T. Since the pressure is controlled, the surge pressure at the time of the emergency stop of the lowering operation is reduced. Further, unlike the first embodiment, since the pump displacement qp is not controlled, even if the rope line pull T changes when the hydraulic pump is a pressure source of another actuator, the drive of the other actuator is adversely affected. Does not affect.

-Seventh Embodiment- A seventh embodiment will be described with reference to FIGS.
FIG. 17 is a hydraulic circuit diagram showing a configuration of a winch control device according to the seventh embodiment of the present invention. Note that FIG.
The same parts as those described above are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG.
Are provided between the pump 17 and the motor 2, between the motor 2 and the tank, between the pump 17 and the tank, respectively.
c is provided. In this case, the amount of driving pressure oil supplied to the hydraulic motor 2 is equal to the flow rate Q passing through the meter-in throttle 3a.
And the flow rate Q passing through the meter-in throttle 3a is
It is generally given by the following equation (II). Q = C × A√ (2 × ΔP / ρ) (II) where C: constant A: throttle area ΔP: differential pressure across the throttle ρ: density

Accordingly, when the stroke amount of the switching valve 2 is constant, when the load acting on the motor 2 is large, the differential pressure ΔP across the throttle 3a decreases, the flow rate Q decreases, and the winch speed decreases. . As a result, even if the maximum drum speed w is controlled with respect to the rope line pull T in the same manner as in the sixth embodiment, the characteristic of the maximum drum speed w is lower than the characteristic A1 as shown by the characteristic A7 in FIG. Therefore, the seventh
In the embodiment, the motor proportional flow rate Q is pressure-compensated, and the characteristic of the electromagnetic proportional valve 1 is set so that the characteristic of the drum maximum speed w becomes the characteristic A1.
8 is controlled. That is, the controller 14 previously stores a characteristic A7 'in consideration of the decrease in the flow rate Q due to the load, and by controlling the driving of the electromagnetic proportional valve 18 along this characteristic A7, the characteristic of the actual drum maximum speed w becomes Characteristic A
It becomes 1.

FIG. 19 is a flowchart showing an example of the processing in the controller according to the seventh embodiment. The same parts as those in FIG. 16 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 19, when the rope line pull T is detected in step S4, the process proceeds to step S36. In step S36, the characteristic A7 'of FIG.
, A drum maximum speed w corresponding to the rope line pull T is calculated, and the process proceeds to step S31. Thereafter, the drum maximum speed w is controlled so as to match the characteristic A7 '.

As described above, according to the seventh embodiment, the switching of the directional control valve 3 is controlled in consideration of the variation in the flow rate Q to the hydraulic motor 2 due to the load fluctuation. Load compensation is performed, and the target characteristic A1 of the maximum drum speed w can be obtained. As a result, the surge pressure during the sudden stop of the motor is reduced as desired.

-Eighth Embodiment- An eighth embodiment of the present invention will be described with reference to FIGS. FIG. 20 is a hydraulic circuit diagram showing a configuration of a winch control device according to the eighth embodiment of the present invention. The same portions as those in FIG. 1 are denoted by the same reference numerals, and the differences will be mainly described below. In the first embodiment, the pump capacity qp is controlled to limit the drum maximum speed w during lowering. However, in the eighth embodiment, the motor capacity qm is controlled to control the motor capacity qm. Limit the maximum drum speed w.

As shown in FIG. 20, the hydraulic motor 20 is of a variable displacement type, the hydraulic pump 17 for supplying the driving pressure oil to the motor 20 is of a fixed displacement type, and the hydraulic pump 12 and the regulator 20a of the hydraulic motor 20 are connected to each other. Between them, an electromagnetic proportional valve 19 is provided. The controller 14 executes a predetermined process based on the signal from the load detector 10 and the signals from the pressure sensors 11A and 11B, and outputs a control signal to the solenoid of the electromagnetic proportional valve 19. Thereby, the pressure oil from the hydraulic pump 12 is reduced to the command pressure ps according to the control signal, the motor capacity qm is controlled, and the hydraulic motor 2
A maximum speed of 0 is limited. In this case, the relationship between the rope line pull T and the drum maximum speed w for reducing the surge pressure at the time of the sudden lowering stop to the allowable value is the same as that shown in the characteristic A1 in FIG. Capacity qm of hydraulic motor 20
Is set to qmmin ≦ qm ≦ qmmax by the regulator 20a.
Can be changed within the range.

FIG. 21 is a flowchart showing an example of the processing in the controller 14 according to the eighth embodiment. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 21, when the drum rotation speed w (rpm) corresponding to the rope line pull T is calculated from the characteristic A1 in FIG. 2 in step S5, the process proceeds to step S41, and the target motor capacity qma is calculated by the following equation (III). I do. qma = qp × np / (w × I) (III) Then, in step S42, the command pressure ps and the motor displacement qm
Then, a command pressure ps to the regulator 20a corresponding to the target motor capacity qma is calculated from the motor characteristic data indicating the relationship with the target motor capacity qma. Subsequently, in step S43, the command pressure ps
Is calculated, and the control signal is output to the solenoid of the electromagnetic proportional valve 19 in step S44 to return to step S1. As a result, the upper limit of the rotation speed of the drum 46 is
Is controlled according to the characteristic A1 in FIG.

On the other hand, if it is determined in step S2 that the operation is a hoisting operation, the flow advances to step S45 to set the target motor displacement qma to the minimum value qmmin. Next, in steps S42 to S44, a control signal for setting the motor 20 to the minimum displacement qmmin is calculated and output to the solenoid of the proportional solenoid valve 19. As a result, the maximum drum speed w becomes the characteristic A0 in FIG.
Is controlled in accordance with If it is determined in step S3 that the operation lever is neutral, the process proceeds to step S46, where the target motor displacement qmmax is set to the maximum value. Then, step S
From 42 to step S44, a control signal for setting the motor 20 to the maximum displacement qmmax is calculated and output to the solenoid of the electromagnetic proportional valve 19. Thus, the rotation speed of the drum 46 is always controlled to the minimum.

As described above, in the eighth embodiment, the motor capacity qm is steplessly controlled based on the rope line pull T to limit the drum maximum speed w during lowering. Can be suppressed below the allowable value. Further, since the pump capacity qp is not controlled, even when the rope line pull T changes when the hydraulic pump is a pressure source of another actuator, the driving of the other actuator is not adversely affected.

In FIG. 21, the rope line T is detected at any time, and the drum maximum speed w is limited based on the detected value T. However, similar to the second embodiment, before the lowering operation is performed. May be stored, and the drum maximum speed w may be limited based on the stored value T0. An example of such a flowchart is shown in FIG.
It is shown in FIG. Thereby, even if the rope line pull T fluctuates at the time of starting the lowering operation, a stable system can be obtained without a change in the motor capacity qm.

Ninth Embodiment A ninth embodiment of the present invention will be described with reference to FIGS. The ninth embodiment differs from the eighth embodiment in the processing performed by the controller 14, and the configuration of the hydraulic circuit is the same as that in FIG. In order to obtain the driving torque required for holding the suspended load 48, the motor capacity qm of the variable motor 20 is controlled according to the holding pressure p1. As a result, rope line pull T and drum 4
As shown in FIG. 22, the relationship between the rotation speed w of the motor 6 and the rotation speed w increases as the rope line pull T increases, so that the motor capacity qm increases and the drum rotation speeds w1 and w2 decrease. In FIG. 22, as described above, the hoisting load acts in the direction of preventing the rotation of the motor 20 during hoisting, so that the drum maximum speed w1 during hoisting is smaller than the drum maximum speed w2 during hoisting. In the ninth embodiment, the maximum drum speed w2 at the time of lowering is matched with the maximum speed w1 of the drum at the time of lowering, thereby reducing the surge pressure at the time of stopping the lowering.

The characteristics at the time of hoisting shown in FIG. 23 are obtained by experiments, simulations and the like, and are stored in the controller 14. FIG. 24 is a flowchart illustrating an example of processing in the controller according to the ninth embodiment.
The same portions as those in FIG. 22 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG.
If it is determined in step S3 that the operation is the lowering operation, the process proceeds to step S4, where the rope line pull T is detected, and the process proceeds to step S47. In step S47, the drum maximum speed w corresponding to the rope line pull T is calculated from the characteristic at the time of winding in FIG. 23, and the process proceeds to step S41. In step S45 or step S46, the target motor capacity qma is reduced to the minimum capacity qmn.
The process proceeds to step S42 as in or the maximum capacity qmmax.
Thus, the lowering speed w2 of the drum 46 when the operation lever 5 is operated to the maximum is limited to be equal to the hoisting speed w1.

As described above, in the ninth embodiment, the motor capacity qm is controlled steplessly, and the drum maximum speed w2 during lowering is controlled.
Has been reduced to the maximum drum speed w1 when hoisting, so that the surge pressure at the time of stopping the lowering operation is reduced, and the hoisting speed and hoisting speed of the suspended load 48 when the operation lever 5 is operated to the maximum. Are the same, and the operability is improved. Also, since the pump capacity qp is not controlled, there is no adverse effect on the driving of other actuators.

-Tenth Embodiment- A tenth embodiment of the present invention will be described with reference to FIGS. FIG. 25 is a hydraulic circuit diagram showing a configuration of a winch control device according to the tenth embodiment of the present invention.
The same portions as those in FIG. 1 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 25, in the tenth embodiment, a winding layer detector 21 for detecting the winding layer N of the rope 45 wound around the drum 46 is additionally provided. The moving speed of the suspended load 48 also depends on the winding layer n of the rope 45. The larger the rope winding layer N, the larger the diameter of the drum 46, and the moving speed of the suspended load 48 even if the maximum drum speed w is the same. Is faster and the suspended load 48
Inertia force of the vehicle increases. Therefore, in the tenth embodiment, the drum maximum speed w is limited according to the rope line pull T and the winding layer N.

FIG. 26 is a diagram showing the relationship between the rope line pull T and the drum maximum speed w for reducing the surge pressure at the time of a sudden stop of the motor to an allowable value or less. The characteristic of the maximum drum speed w at the maximum is shown, and the characteristic Nmin shows the characteristic of the maximum drum speed w when the winding layer N is the minimum. As described above, since the inertia force of the suspended load 48 increases as the rope winding layer N increases, the drum maximum speed w for reducing the surge pressure to an allowable value or less, as shown in FIG. It gets smaller. The controller 14 controls the characteristics Nmin and Nmax of the maximum drum speed for each winding layer.
And the pump capacity qp along with those characteristics
Control.

FIG. 27 is a flowchart showing an example of the processing in the controller 14 according to the tenth embodiment. The same parts as those in FIG.
Hereinafter, the differences will be mainly described. As shown in FIG. 27, when the rope line pull T is detected by the signal from the load detector 10 in step S4, the process proceeds to step S51,
The rope winding layer N is detected based on a signal from the winding layer detector 21. Next, in step S52, the drum maximum speed w corresponding to the detected values of the rope line pull T and the rope winding layer N is calculated from the relationship of FIG. 26, and the process proceeds to step S6. As a result, the drum rotation speed w at the time of the maximum lever operation is limited to different characteristics for each rope winding layer.

As described above, in the tenth embodiment, since the pump capacity qp is controlled in accordance with the rope line pull T and the rope winding layer N, the surge pressure can be ensured regardless of the size of the winding layer N. Below the allowable value. Therefore, it is not necessary to perform an operation in consideration of the increase in the moving speed of the suspended load due to the thickening of the winding.
Can be rotated at a high speed, thereby increasing the working efficiency.

In the above-described embodiment, the maximum drum speed w is limited in accordance with the rope line pull T. However, if the drum motor has a correlation with the load acting on the hydraulic motor 2, other than the rope line pull may be used. The maximum drum speed w may be limited according to the following. In the above-described embodiment, the drum maximum speed w is limited along a characteristic in which the drum maximum speed w decreases as the rope line pull T increases (so-called downward-sloping characteristics A1, A3, A5, etc.). However, the shape of these characteristics does not necessarily have to be right-downward for all rope line pulls T, and may have a horizontal characteristic portion depending on the value of the rope line pulls T. An example is shown in FIG. In the characteristic Ac of FIG. 28, the drum maximum speed w has a predetermined value wc above the rope line pull Tc. By determining the lower limit of the drum maximum speed w, the surge pressure can be effectively reduced without sacrificing usability.

Further, in the above embodiment, the pump displacement qp, the motor displacement qm, the control valve 3 and the like are steplessly controlled according to the rope line pull T. However, unless the rope maximum speed w changes abruptly. It is not always necessary to perform stepless control, and control may be performed stepwise gradually.
Furthermore, in the above-described embodiment, the drum maximum speed w when the hydraulic motor 2 lowers is limited. However, when the surge pressure at the time of lowering is reduced, the same as when lowering. The maximum drum speed w at the time may be limited. Further, the first to tenth embodiments may be configured to be variously combined.

In the correspondence between the above embodiment and the claims, the load detector 10 or the pressure sensor 15 or the pressure sensor 15 serves as a load detecting means, and the regulator 1a and the electromagnetic proportional valve 13, or the electromagnetic proportional valve 18, or the regulator. 20a and the proportional solenoid valve 19 control the rotation speed limiting means, the controller 14 controls the control means, the regulator 1a and the proportional solenoid valve 13 control the pump displacement control device, and the regulator 20a and the proportional solenoid valve 19 control the motor displacement control device. Valve 18
Constitutes a control valve control device, and the wound layer detector 21 constitutes a wound layer detecting means.

[0059]

As described above, according to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, at least at the time of the lowering operation of the operation lever, in accordance with the detection result from the load detecting means, the maximum rotational speed of the hydraulic motor becomes lower as the load becomes larger. Is limited, the maximum motor speed range can be obtained in a state where the surge pressure is kept below the allowable value, and the behavior of the suspended load when the load changes can be made smooth. (2) According to the second aspect of the invention, the maximum rotation speed of the hydraulic motor is limited based on the load detection result before the operation lever is operated to lower the load. Even if it fluctuates, stable lowering can be performed without changing the maximum rotation speed of the motor. (3) According to the third aspect of the invention, the maximum rotation speed of the hydraulic motor is set so that the limit value of the maximum rotation speed during the lowering operation is substantially equal to the maximum rotation speed of the hoisting rotation speed by the horsepower control. Since the restriction is made, the hoisting speed and the hoisting speed of the suspended load with respect to the operation of the operation lever become equal, and the operability is improved. (4) According to the invention of claim 5, the maximum rotational speed of the hydraulic motor is limited by controlling the motor capacity. According to the invention of claim 6, the maximum rotational speed of the hydraulic motor is controlled by controlling the control valve. Since the restriction is made, even if the hydraulic pump is a pressure source for another actuator, the load fluctuation does not adversely affect the other actuator. (5) According to the seventh aspect of the present invention, the drive of the control valve is controlled so that the differential pressure across the control valve becomes substantially constant regardless of the load. Even if there is, the maximum rotation speed of the hydraulic motor can be limited to a target value. (6) According to the invention of claim 8, since the maximum number of revolutions of the hydraulic motor is limited according to the holding pressure, it is not necessary to detect the load with a load detector such as a load cell, and the winch control device. Can be constructed at low cost,
Even when a plurality of winches are used simultaneously, the speed of each winch can be independently limited. (7) According to the ninth aspect of the invention, the maximum rotation speed of the hydraulic motor is limited in accordance with the hoisting driving pressure of the motor, so that it is not necessary to provide a pressure sensor or the like in the holding pipeline.
Therefore, the pressure oil does not flow out of the holding pipeline due to breakage of the pressure sensor or the like. (8) According to the tenth aspect, the maximum rotation speed of the hydraulic motor is limited in accordance with the winding layer detected by the winding layer detection means, so that the surge pressure can be reliably maintained regardless of the size of the winding layer. Below the allowable value. (9) According to the eleventh aspect, when the load exceeds a predetermined value, the maximum rotation speed of the hydraulic motor is set to the lower limit value. Therefore, the surge pressure can be effectively reduced without sacrificing usability. Reduced.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a configuration of a winch control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing characteristics of a maximum drum speed of a winch control device according to the first embodiment.

FIG. 3 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the first embodiment;

FIG. 4 is a side view of a crane having a winch control device according to the embodiment of the present invention.

FIG. 5 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the second embodiment;

FIG. 6 is a view showing a characteristic of a maximum drum speed of a winch control device according to a third embodiment.

FIG. 7 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the third embodiment;

FIG. 8 is a flowchart showing another example of the processing in the controller constituting the winch control device according to the third embodiment.

FIG. 9 is a hydraulic circuit diagram showing a configuration of a winch control device according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a characteristic of a maximum drum speed of a winch control device according to a fourth embodiment.

FIG. 11 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the fourth embodiment;

FIG. 12 is a hydraulic circuit diagram showing a configuration of a winch control device according to a fifth embodiment of the present invention.

FIG. 13 is a diagram illustrating characteristics of a maximum drum speed of a winch control device according to a fifth embodiment.

FIG. 14 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the fifth embodiment;

FIG. 15 is a hydraulic circuit diagram showing a configuration of a winch control device according to a sixth embodiment of the present invention.

FIG. 16 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the sixth embodiment;

FIG. 17 is a hydraulic circuit diagram showing a configuration of a winch control device according to a seventh embodiment of the present invention.

FIG. 18 is a view showing a characteristic of a maximum drum speed of a winch control device according to a seventh embodiment.

FIG. 19 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the seventh embodiment;

FIG. 20 is a hydraulic circuit diagram showing a configuration of a winch control device according to an eighth embodiment of the present invention.

FIG. 21 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the eighth embodiment;

FIG. 22 is a flowchart illustrating another example of the processing performed by the controller included in the winch control device according to the eighth embodiment;

FIG. 23 is a hydraulic circuit diagram showing a configuration of a winch control device according to a ninth embodiment of the present invention.

FIG. 24 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the ninth embodiment;

FIG. 25 is a hydraulic circuit diagram showing a configuration of a winch control device according to a tenth embodiment of the present invention.

FIG. 26 is a view showing characteristics of a maximum drum speed of the winch control device according to the tenth embodiment.

FIG. 27 is a flowchart illustrating an example of a process performed by a controller included in the winch control device according to the tenth embodiment;

FIG. 28 is a diagram showing another characteristic of the maximum drum speed of the winch control device according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hydraulic motor 1a Regulator 2 Hydraulic motor 3 Directional control valve 5 Operating lever 8 Counter balance valve 10 Load detector 13 Electromagnetic proportional valve 14 Controller 15 Pressure sensor 16 Pressure sensor 17 Hydraulic pump 18 Electromagnetic proportional valve 19 Electromagnetic proportional valve 20 Hydraulic motor 20a Regulator 21 winding layer detector

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F15B 11/02 F 11/04 B

Claims (11)

[Claims] 1. A hydraulic pump, a hydraulic motor that is rotated by hydraulic oil discharged from the hydraulic pump, and a hydraulic pump that is driven in response to an operation of an operation lever and controls a flow of hydraulic oil from the hydraulic pump to the hydraulic motor. A winch control device having a control valve, a load detecting means for detecting a physical quantity having a correlation with a load acting on the hydraulic motor, a rotational speed limiting means for limiting a maximum rotational speed of the hydraulic motor, at least an operation A control unit that controls the rotation speed limiting unit so that the larger the load, the lower the maximum rotation speed is, in accordance with the detection result from the load detection unit, during a lever lowering operation. Winch control device. 2. The winch control device according to claim 1, wherein the control unit stores a detection result by the load detection unit before the operation lever is operated to lower the operating lever, and based on the stored value. A winch control device for controlling the rotation speed limiting means. 3. The winch control device according to claim 1, wherein the control means controls a maximum rotation speed during a hoisting operation in which a limit value of the maximum rotation speed during the hoisting operation is determined by horsepower control. A winch control device for controlling the rotation speed limiting means so as to be substantially equal in number to the number of rotations. 4. The winch control device according to claim 1, wherein the rotation speed limiting device has a pump displacement control device that controls a displacement of the hydraulic pump, and the control device includes: A winch control device for controlling the pump displacement control device in accordance with a detection result from the load detection means. 5. The winch control device according to claim 1, wherein the rotation speed control unit has a motor displacement control device that controls a displacement of the hydraulic motor, and the control unit includes: A winch control device for controlling the motor displacement control device according to a detection result from the load detection means. 6. The winch control device according to claim 1, wherein the rotation speed limiting device has a control valve control device for controlling a driving amount of the control valve, and the control device includes: A winch control device for controlling the control valve control device according to a detection result from the load detection means. 7. The winch control device according to claim 6, wherein the control means controls the control valve control device such that a differential pressure across the control valve is substantially constant regardless of a load on the hydraulic motor. Control device for controlling a winch. 8. The winch control device according to claim 1, wherein the physical quantity is a holding pressure of the hydraulic motor. 9. The winch control device according to claim 1, wherein the physical quantity is a hoisting driving pressure of the hydraulic motor. 10. The winch control device according to claim 1, further comprising a winding layer detecting unit that detects a winding layer, wherein the control unit detects the winding layer. A winch control device for controlling the rotation speed limiting means according to a layer. 11. The winch control device according to claim 1, wherein the control means sets the maximum rotation speed to a lower value as the load increases, and sets the maximum rotation speed to a predetermined value when the load exceeds a predetermined value. The control device for a winch, wherein the rotation speed limiting means is controlled so as to have a lower limit value.