WO1996028377A1

WO1996028377A1 - Method and system for controlling the speed of a winch

Info

Publication number: WO1996028377A1
Application number: PCT/JP1995/000394
Authority: WO
Inventors: Kinya Mori
Original assignee: Komatsu Ltd.; Komatsu Mec Kabushiki Kaisha
Priority date: 1995-03-10
Filing date: 1995-03-10
Publication date: 1996-09-19
Also published as: EP0819646A4; KR19980702858A; EP0819646A1

Abstract

A method and system for controlling the speed of a winch which can improve the safety and operability thereof without being put into a free fall state and obtain a lowering speed which is the same as what would be obtained in the free fall state. In order to make this happen, the rotation speed of a winch drum (13) is kept substantially at a unique one relative to the stroke of an operation lever (5) until the operation lever (5) reaches a predetermined stroke, while it becomes different relative to the same stroke of the operation lever (5) in accordance with a speed mode selected from a plurality of speed modes when the operation lever exceeds the predetermined stroke.

Description

Method for controlling the speed of a harmful punch and its system

The present invention relates to a winch speed control method and system, and more particularly to a winch speed control method and system for driving a winch drum by hydraulic pressure.

Background technology

Conventionally, a winch device used for a crane or the like includes, for example, a main winch 50 and a capture winch 60 as shown in FIG. The main winding winch 50 driven by hydraulic pressure is connected to a hydraulic motor 51, a speed reducer 52 driven by the hydraulic motor 51, an output shaft 52 a of the speed reducer 52, and a main drum 56. And a clutch 53 interposed between the fixed drive shafts 55. A brake drum 54a is fixed to the flange portion of the main drum 56, and a nozzle brake 54 is wound around the brake drum 54a.

With this configuration, the rotation of the hydraulic motor 51 is accelerated by the speed reducer 52 and transmitted to the output shaft 52a, and when the clutch 53 is connected, the main drive is driven via the drive shaft 55. Is transmitted to system 56. By controlling the rotation of the hydraulic motor 51 by a known method, the rotation of the main drum 56 can be controlled according to the rotation of the hydraulic motor 51. In addition, when lowering light loads such as hooks in a short time, or when the hammering of the hammer by free fall is required, such as in piles and pile driving in civil engineering work, the winch is used. Used in leaffall prone. In these cases, when the clutch 53 is opened, the suspended load of the main winch 50 is in a free falling state. When controlling the falling speed, the brake 54 is pressed against the brake drum 54a, and the braking force is adjusted according to the degree of pressing. As described above, it is used in the free fall state. When using it, a light load can be dropped in a short time or a large impact force can be obtained with a heavy object such as a hammer. Note that the configuration and operation of the auxiliary winch 60 are the same as those of the main winch 50, and a description thereof will be omitted.

However, according to the above-mentioned prior art, when the winch is used in a free fall state, the suspended load descends at a very high speed regardless of the operator's intention, and the suspended load is stopped at a predetermined position. Becomes difficult. There was also a danger that the winch suddenly went into a free fall state due to an erroneous operation of the lever, causing the suspended load to fall, and considerable tension was imposed on the workers. Disclosure of the invention

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the related art, and the drive device for the winch drum and the winch drum are always in a connection state to eliminate the free-full state. It is another object of the present invention to provide a winch speed control method and a system for improving the safety and operability of an operator.

In the method of controlling the speed of the winch according to the present invention, the rotational speed of the winch drum is substantially univocal relative to the stroke of the operating lever up to a predetermined stroke of the operating lever. Above the stroke, the number of rotations for the same stroke of the operating lever is different depending on the speed mode selected from a plurality of speed modes. The selected speed mode may be switched to another speed mode in a stroke in the middle of a predetermined stroke or more. The switching of the speed mode may be possible under a preset condition when switching from the low speed mode to the high speed mode. Furthermore, the winch drum rotation speed up to a predetermined stroke may gradually increase in response to the increase in the stroke of the operation lever, and may be the same among a plurality of speed modes.

According to such a configuration, in each speed mode, the winch drum rotation speed up to a predetermined stroke is the same, so that the operator has a common operational feeling at the start of operation, and good operability is obtained. In addition, if the stroke exceeds a certain value, for example, the speed will increase By selecting the speed mode, the operating speed increases and the work efficiency improves. Furthermore, when the winch drum rotation speed is gradually increased, the fine operability is improved by lowering the rotation speed at the start of operation. As described above, different speed modes can be selected as necessary, and high operability can be obtained.

The first invention of the winch speed control system according to the present invention includes a regulator for supplying a control pressure corresponding to a pilot pressure to a control cylinder of a variable hydraulic motor, and a pilot valve for a pilot-operated valve. A pilot line for connecting a pilot valve for supplying a pilot pressure, and a mode switching valve for communicating or shutting off the pilot port line are provided. A setting means is provided in the regulator, and the setting means stops the operation of the regulator until a predetermined pilot pressure is reached. When the pilot pressure is equal to or higher than a predetermined pilot pressure, the variable type is controlled according to a control pressure of a regulator. The specific volume of the hydraulic motor may be reduced. The mode switching on / off valve is a solenoid-driven mode switching on / off valve having a solenoid. An electrical signal may be output to the In addition, a throttle device S may be provided in the control pressure pipeline connecting the control cylinder and the control cylinder. Further, there are provided a placement control means for the variable hydraulic motor, a connection means for connecting the capacity control means and the piston port of the control cylinder, and a placement setting means comprising a capacity setting member and a stove. The displacement setting member is fixed to one of the displacement control means, the piston rod, and the connection means to set the minimum displacement of the variable hydraulic motor, and the stopper regulates movement of the displacement setting member. Alternatively, it may be canceled. According to such a configuration, in a state where the regulator and the pilot valve are in communication with each other, the winch drum is controlled by the pilot-type operation valve and the variable hydraulic motor whose fixed capacity is reduced by the control cylinder. The rotation speed is controlled. On the other hand, since the regulator is not operated in the shut-off state, the control pressure of the regulator is not supplied to the control cylinder of the variable hydraulic motor. Therefore, the winch drum rotation speed is controlled only by the pilot operated valve operated in accordance with the pilot pressure. In addition, when the setting means (for example, a spring attached to the regulator) is provided, the control cylinder is not supplied with the control pressure of the regulator until the predetermined stroke of the operation lever, so that the pilot-type operation is performed. The valve controls the winch drum speed. On the other hand, when the operating lever crosses the predetermined stroke, the specific volume of the variable hydraulic motor decreases due to the control pressure of the regulator in accordance with the pilot pressure. Accordingly, the winch drum rotation speed is controlled by the reduced specific volume and the pilot operated valve. If the mode switching valve is shut off at this time, the winch drum rotation speed is controlled only by the pilot type operation valve, and therefore decreases with respect to the stroke of the same operation lever.

As described above, up to a predetermined stroke, the winch drum rotation speed is almost uniquely determined with respect to the stroke of the operation lever, regardless of whether the mode switching on-off valve is connected or disconnected. On the other hand, when the stroke exceeds the predetermined stroke, the winch drum rotation speed becomes the rotation speed corresponding to each mode even if the operation lever is the same stroke.

When a switch is mounted on the control lever knob, the speed mode can be switched by the switch while controlling the winch drum rotation speed with the control lever. In addition, when the above-described expansion device is provided, there is no sudden change in the specific capacity of the variable hydraulic motor, so that a rapid change in the winch drum rotation speed can be prevented. As a result, the safety and the durability of the device can be improved. Further, by providing the above-mentioned capacity setting means, when the stopper regulates the movement of the capacity setting member, the variable hydraulic motor has a predetermined minimum specific volume. On the other hand, when the movement restriction is released, the specific volume of the variable hydraulic motor can be reduced to 0, and the winch can be operated in a free-full state.

Next, in a second invention of the winch speed control system, a selection valve is provided, and the selection valve controls the pressure between the predetermined pressure of the pressure source and the driving pressure of the variable hydraulic motor that drives the winch drum. It is characterized in that the higher pressure is selected from among these and is supplied as the original pressure for the regiure.

According to this configuration, the control pressure supplied to the control cylinder of the variable hydraulic motor is such that the predetermined pressure of the pressure source is the original pressure while the drive pressure of the variable hydraulic motor is low. On the other hand, When the dynamic pressure increases, this drive pressure becomes the original pressure of the regulator and is supplied to the control cylinder of the variable hydraulic motor, so that the specific volume of the variable hydraulic motor can be reliably controlled. .

Next, a third invention of the winch speed control system comprises a relief valve for controlling the return hydraulic pressure of the hydraulic motor to a predetermined pressure when the winch drum is lowered, and a relief valve installed at a connection between the hydraulic motor and the winch drum. A switching valve is provided between the negative brake and the negative brake, and this switching valve communicates or shuts off the pilot pressure for releasing the function of the relief valve and the pilot pressure for opening the negative brake. And

According to such a configuration, when the switching valve is switched to the communication position, the pilot pressure for releasing the function and the pressure for opening the pilot are supplied, and the winch drum can be rotated once. Maintenance inspection becomes easy. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a control circuit diagram for the main winding pinch and a part of the auxiliary winding inch according to the embodiment of the present invention,

FIG. 2 is a chart illustrating Hi / rated mode, Hi / high-speed mode, L0-no rated mode, and LoZ high-speed mode, which are the speed modes according to the embodiment.

FIG. 3 is a diagram for explaining the speed control system of the winch according to the embodiment, and is a chart showing the relationship between the operation stroke of the main winding winch and the rotation speed of the winch drum, and FIG. 4 is a main winding winch according to the embodiment. Cross section of the

FIG. 5 is a schematic diagram of a ゥ inch apparatus according to the related art. BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the method and system for controlling the speed of a winch according to the present invention will be described in detail below with reference to the accompanying drawings.

In Fig. 1, 1 is a winch pump for driving a winch, 3 is a pressure compensation valve, 4 is a pilot operated valve, 5 is an operating lever for operating a winch, and 5a is a pilot operated valve. A pilot valve for supplying pilot pressure to the valve operation 4 etc., and 5 b is a high-speed mode switching button. Reference numeral 6 denotes a hydraulic motor (in this embodiment, a variable hydraulic motor is used); 6b, a splash plate (capacity control means) provided in the hydraulic motor 6; 7a, a check valve; A relief valve, 8 is a control pump (pressure source) for supplying the control pressure of this speed control system, 9 is a switching valve for supplying the control pressure of the motor, and 9a is a control of the auxiliary winding winch. A switching valve for supplying pressure, 11 is a switching valve for the source pressure of the pilot port of the pilot pump 8 maintained at a constant pressure by the relief valve 10, and 12 is built in the hydraulic motor 6. A negative brake 13 is a winch drum driven by a hydraulic motor 6.

Reference numeral 18 denotes a high-speed mode switching valve for switching the pilot pressure of the pilot valve 5a output via the shuttle valve 23, and reference numeral 19 denotes a high-speed mode switching valve provided via the high-speed mode switching valve 18. Pilot pressure and setting spring (setting means) Regulating unit for capacity control of hydraulic motor 6 controlled by the difference between 19a spring force and 20 are control cylinders for hydraulic motor 6, 20 a is a link (connection means) for connecting the piston rod of the control cylinder 20 to the splash plate 6b, and 21 is a throttle provided in a control pressure line to the control cylinder 20. Reference numeral 22 denotes a relief valve provided between the main driving lines of the hydraulic motor 6.

Further, reference numeral 24 denotes a controller, and reference numeral 24a denotes an AND circuit constituting the controller 24. Under the predetermined conditions, for example, in the case of this embodiment, the AND circuit 24a has (i) the 0N signal of the high-speed mode switching button 5b, and (ii) the lower-side pilot pressure of the pilot valve 5. When the signals P d and (Si) the predetermined rope tension signal T s are simultaneously inputted, an excitation signal is outputted to the solenoid 18 a of the high-speed mode switching valve 18. The reasons for setting (ii) and (Hi) as the conditions for restricting the switching to the high-speed mode are as follows. That is, condition (ii) is a problem when speeding up the hoisting work, for example, excessive winding due to irregular winding of the rope due to deterioration of the winding ability of the rope on the drum, or sudden stop when the hook is overwound. This is to avoid the occurrence of a click. Condition (iii) is that even if the lifting load exceeds the holding capacity of the hydraulic motor, This is to prevent lowering. In addition, in (iii), during normal work, heavy loads are wound up at a high speed and are rarely unwound. The purpose is to prevent unnecessary loads and increase safety. Here, the rope tension is an input signal corresponding to the suspension load, and a load that directly acts on the winch device from the outside is an input signal. The rope tension can be obtained, for example, by dividing the suspension load obtained via the overload prevention device by the hook number of the hook previously input.

Reference numeral 27 denotes a low-pressure relief valve provided in the winch lowering line, reference numeral 28 denotes a tank, reference numeral 30 denotes a drum free switch, reference numeral 31 denotes a drum free switching valve, and reference numeral 32 denotes a brake. A throttle provided in a pipeline that supplies the pilot pressure of the pilot pump 8 to the negative brake 12 via the valve 11, 33 is a solenoid-operated on-off valve, 34 is a capacity setting cylinder 34 a Capacity setting means including a capacity setting member 34 b fixed to the piston rod of the control cylinder 20, 35 a, 35 b and 35 c are check valves. Next, the operation of the above configuration will be described.

The speed modes of the present embodiment include four modes, i.e., Hi rated mode and Hi no high speed mode at high engine speed, and L0 rated mode and L0 no high speed mode at low engine speed. .

First, the operation of the main winch common to each speed mode of the present embodiment will be described. The auxiliary winding winch is the same as the main winding winch, and the description is omitted. In FIG. 1, when the operation lever 5 is operated, a pilot pressure corresponding to the operation amount is output from the pilot valve 5a, and the pilot-type operation valve 4 is operated. A flow rate corresponding to the operation amount of the pilot operated valve 4 is supplied from the winch pump 1 and a boom pump (not shown) to the hydraulic motor 6 and is taken out from the pilot operated valve 4 at the same time. The switching valve 9 is switched to the position b by the load pressure. As a result, the control pressure of the pilot pump 8 is supplied to the brake valve 11 via the b position of the switching valve 9 and the throttle 32, so that the braking of the negative brake 12 is released. With this release, the winch drum 13 is moved to the operation amount of the operation lever 5. It rotates at the corresponding rotation speed.

When the operation lever 5 is suddenly operated to the lowering side, the winch drum 13 tries to rotate rapidly to the lowering side, but the relief valve 27 set at a predetermined pressure causes the lowering line to be operated. Since the hydraulic oil of the wire is relieved, a sudden increase in the number of revolutions to the lowering side is prevented, and irregular winding of the wire can be prevented.

When the winch drum 13 is to be free-rotated, the drum free switch 30 is turned on, so that the drum free switching valve 31 is at the b position and the brake valve 11 is at the a position. become. As a result, the negative brake 12 is released by the control pressure of the control pump 8, and the control pressure of the control pump 8 is supplied to the relief valve 7b. Will be able to make a full turn on the unwinding side.

As another free rotation operation, first, an electric signal of a switch (not shown) is output to the solenoid of the brake valve 11, the brake valve 11 is set to the a position, and the negative brake 1 2 To release. At the same time, an electric signal is also output to the solenoid of the solenoid on-off valve 33, and by setting the solenoid on-off valve 33 to the b position, the control pressure of the control pump 8 is set to the capacity. It is supplied to the rod chamber of the cylinder 34a and the control cylinder 20. As a result, the rod (stopper) of the capacity setting cylinder 34a contracts, and the movement restriction of the capacity setting member 34b is released. The released capacity setting member 34 b moves the splash plate 6 b via the piston rod of the control cylinder 20 and the link 20 a, and the hydraulic motor 6 Set capacity to 0 cc / rev. Therefore, if a higher unwinding speed than the Hi-no high-speed mode is required, by setting the capacity of the hydraulic motor 6 to Occ / rev as described above, even if the clutch is omitted, the flywheel can be removed. Work is possible.

FIG. 2 shows four speed modes of the present embodiment. Here, the engine speed is expressed in two states, i.e., Hi state corresponding to the high idle rotation state and L 0 state corresponding to the low idle rotation state, for the sake of simplicity. However, the actual use condition may be set to a state corresponding to an intermediate point. Also engine Even if the rotation speed of the hydraulic motor is constant, the maximum flow rate to the hydraulic motor can be changed by changing the number of hydraulic pumps that supply hydraulic oil to the hydraulic motor according to the specific volume or speed mode of the hydraulic pump. , L i, L 0, or an intermediate state thereof. Further, in the high-speed mode, the specific volume of the hydraulic motor is changed from V to 0.5 V, but the minimum specific volume is not limited to 0.5 V. Therefore, it is of course possible to appropriately select the high-speed mode and to set a plurality of the minimum specific volumes.

FIG. 3 is an explanatory diagram of a winch speed control system having the above configuration. Each mode at the time of lowering by the main winch shown on the right side of FIG. 3 will be described with reference to the operating conditions of FIG. 2 and FIG.

(1) In case of Hi-no rated mode

Between the lever strokes N to S1, there is a dead zone due to oil leaking from hydraulic equipment such as the hydraulic pump 1 and the hydraulic motor 6, and the winch drum 13 does not rotate. The winch drum 13 between the lever strokes N to S1 does not rotate in any of the Hi-no high speed mode, the Lo rated mode, and the Lo high speed mode described later. Next, the number of rotations of the drum between the lever strokes S 1 to S 6 is increased up to N 6 by the flow rate determined by the opening characteristic of the pilot operated valve 4. The drum rotation speed is shown with the rated rotation speed N 6 being 100%.

(2) Hi-Z high-speed mode

The pilot pressure signal Pd and the rope load signal TS, which is a predetermined safety load, output from the pressure switch (installed in the pipe line on the lower side of the pilot valve type operation valve 4) are When the high-speed mode switching button 5b of the control lever 5 is pressed while the signal is input to the AND circuit 24a of the controller 24, the high-speed mode is switched by the signal from the AND circuit 24a. Valve 18 switches to position b.

Therefore, according to the lever stroke of the operating lever 5, The pilot pressure of the pilot valve 5a is supplied to the volume control regulator 19. However, between the lever strokes SI and S4, the pressing force due to the pie mouth pressure increases the spring force of the setting spring 19a. Since the force is set smaller than the force, the displacement control regulator 19 remains at the b position.

The number of rotations of the drum between the lever strokes SI to S4 increases up to N4 due to the opening characteristics of the pilot operated valve 4. The range between S I and S 4 is exactly the same as the Hino rated mode. When the lever stroke reaches S4, the pressing force of the displacement control regulator 19 becomes larger than the spring force of the setting spring 19a, and the displacement control regulator 19 starts to be operated in the a direction.

Between the lever strokes S 4 and S 5, the inherent fertility of the hydraulic motor 6 is reduced from V to 0.5 V by the pie mouth pressure according to the lever stroke, and the pie mouth operated valve 4 is used. As the flow rate increases, the rotation speed of the winch drum 13 increases up to N 7. In other words, the winch drum rotation speed in S4 to S5 is twice the Hi-no rated mode. Since the specific volume of the hydraulic motor 6 is constant between the lever strokes S5 and S6, and the amount of increase in the flow rate due to the opening characteristics of the pilot valve 4 due to the lever stroke is small, the winch drum rotates. The number is constant at N 7.

In the lever strokes S4 to S6, the position is switched from the position P to the position Q by releasing the pressing of the high-speed mode switching button 5b. Conversely, pressing the high-speed mode switching button 5b allows switching from position Q to position P.

The source pressure of the displacement control regulator 19 is controlled by the higher drive pressure of the hydraulic motor 6 selected by the check valves 35 a and 35 b and the relief pressure by the relief valve 10. A high oil pressure is selected by the check valve 35c (selection valve) with the discharge pressure of the control pump 8 held at the pressure. The original pressure is reduced according to the operation amount of the regulator 19 in accordance with the lever stroke, and is supplied to the control cylinder 20 of the hydraulic motor 6. Therefore, the control pressure supplied to the control cylinder 20 is ensured by the discharge pressure of the control pump 8 maintained at a predetermined pressure while the drive pressure of the hydraulic motor 6 is low. On the other hand, when the driving pressure of the hydraulic motor 6 increases, this driving pressure increases Since it is supplied to the control cylinder 20 as the source pressure of the gear 19, the capacity of the hydraulic motor 6 can be reliably controlled.

(3) Lo rated mode

The rotation speed of the winch drum between the lever strokes SI to S3 increases to a maximum of N3 due to the opening characteristics of the pilot operated valve 4. Next, the number of rotations of the winch drum between the lever strokes S3 and S6 is N3 because the flow rate flowing into the pilot valve 4 is a predetermined maximum flow rate (constant) corresponding to the Lo rated mode. It remains constant.

(4) Lo high speed mode

The winch drum rotation speed is increased to a maximum of N3 by the pilot valve 4 between the lever strokes S1 and S3, and is constant N3 between the lever strokes S3 and S4. Therefore, the winch drum rotation speed between SI and S4 is the same as the Lo rated mode. The rotation speed of the winch drum 13 between the lever strokes S4 and S5 is determined by the capacity reduction of the hydraulic motor 6 according to the lever stroke and the opening characteristics of the pilot operated valve 4, as in the Hi-no high-speed mode. Depending on the increase in the flow rate, the speed is reduced up to N5. The winch drum rotation speed between the lever strokes S5 to S6 is a constant rotation speed N5 because the specific volume of the hydraulic motor 6 is constant and the flow rate increase due to the increase in the lever stroke is small.

Also, as in the case of the Hi-no high-speed mode, when the high-speed mode switching button 5b is released between the lever strokes S4 and S6, the position is switched from the position T to the position S. It is possible to switch from position S to position T by pressing high-speed mode switching button 5b.

For example, when changing from the Lo Z high-speed mode to the Hi rated mode, it is possible to increase the engine speed in advance and then switch to the Hi no rated mode.

As described above, each mode at the time of lowering by the main winding winch has been described. However, the lever stroke and winch drum rotation on the hoisting side of the main winding winch (left side in FIG. 3) are described. The relationship with the number of turns is the same as that of the Hi-rated mode and the LoZ-rated mode on the unwinding side, the absolute value is the same, and the rotation direction is reversed. Further, the auxiliary winding winch is the same as the main winding winch, and the description is omitted. In FIG. 4, 6a is a main shaft of the hydraulic motor 6, 12 is a negative brake, 13a is a planetary reduction gear of the winch drum 13, and 16 is a rope wound around the winch drum 13. The operation of this configuration will be described. When hydraulic oil is supplied from a hydraulic line (not shown) to the hydraulic motor 6, the main shaft 6 a rotates at a rotational speed determined by the hydraulic oil flow rate and the specific volume of the hydraulic motor 6. The rotation of the main shaft 6a is reduced by the planetary decelerator 13a to rotate the winch drum 13 in the hoisting or lowering direction. As a result, the rope 16 hoists or lowers the suspended load. The auxiliary winding winch is symmetrical to the main winding winch in FIG. 4 and will not be described. Industrial applicability

According to the present invention, by always dynamically connecting the winch drum to the drive source, safety and operability are improved without a free fall state, and the unwinding speed equivalent to a free fall can be achieved by a simple operation. It is useful as a method for controlling the speed of the obtained winch and its system.

Claims

The scope of the claims

1. In the method of controlling the speed of the winch drum by controlling the rotation of the winch drum by the operation lever, the rotation speed of the winch drum is controlled until the predetermined talk of the operation lever. The rotation speed becomes almost univocal with respect to the stroke, and above a predetermined stroke, different rotation speeds for the same stroke of the operating lever are selected according to the speed mode selected from a plurality of speed modes. A winch speed control method.

2. The winch speed control method according to claim 1, wherein the selected speed mode is switched to another speed mode in a stroke in the middle of the predetermined stroke or more. .

3. The winch according to claim 2, wherein the switching of the speed mode is possible under a preset condition when switching from the low speed mode to the high speed mode. Speed control method.

4. The winch drum rotation speed up to the predetermined stroke gradually increases in accordance with the stroke of the operating lever, and is the same among the plurality of speed modes. The winch speed control method according to claim 1.

5. A hydraulic pump, a variable hydraulic motor that drives a winch drum, and a pilot-operated valve that is interposed between the hydraulic pump and the variable hydraulic motor and controls the rotation speed of the winch drum. A pilot valve for supplying pilot pressure to the pilot type operation valve; and a regulator for supplying a control pressure corresponding to the pilot pressure to a control cylinder of the variable hydraulic motor. In a winch speed control system, a pilot line connecting the regulator and the pilot valve is provided; A winch speed control system, comprising: a mode switching on-off valve for communicating or shutting off the pilot pipe line.

6. A setting means is provided in the regulator, and the setting means stops the operation of the regulator until a predetermined pilot pressure is reached. When the pilot pressure is higher than a predetermined pilot pressure, the setting means stops the operation of the regulator. 6. The winch speed control system according to claim 5, wherein the specific volume of the variable hydraulic motor is reduced according to the control pressure of the regulation.

7. The mode switching on-off valve is a solenoid-driven mode switching on-off valve having a solenoid, and a switch is provided on an operation lever knob of the pilot valve. 6. The winch speed control system according to claim 5, wherein an electric signal is output from a switch to the solenoid.

8. The winch speed control system according to claim 5, wherein a throttling device is provided in a control pressure line connecting the regulator and the control cylinder.

9. Capacity control means for the variable hydraulic motor, capacity connection means for connecting the capacity control means to the piston port of the control cylinder, capacity setting member and a stove Means, and the capacity setting member is fixed to any one of the capacity control means, the piston port, and the connection means, and sets a minimum capacity S of the variable hydraulic motor. 6. The winch speed control system according to claim 5, wherein the stop is set, and the stop regulates or releases the movement of the capacity setting member.

10. A hydraulic pump, a variable hydraulic motor for driving a winch drum, and a pilot-operated valve interposed between the hydraulic pump and the variable hydraulic motor to control the rotation speed of the winch drum Supply pilot pressure to the pilot operated valve A winch speed control system comprising: a pilot valve for controlling the pilot pressure; and a regulator for supplying a control pressure corresponding to the pilot pressure to a control cylinder of the variable hydraulic motor. The selector valve selects the higher pressure out of the predetermined pressure of the pressure source and the driving pressure of the variable hydraulic motor, and supplies the higher pressure as the original pressure of the regulator. Dinch speed control system characterized by the following.

1 1. A hydraulic pump, a hydraulic motor for driving a winch drum, an operation valve interposed between the hydraulic pump and the hydraulic motor to control the rotation speed of the winch drum, and a hydraulic pressure connecting these. A drive line, a relief valve interposed on the winch drum winding side of the hydraulic drive line to control the return hydraulic pressure of the hydraulic motor to a predetermined pressure when the winch drum is lowered; In a winch speed control system including a negative brake installed at a connection between the hydraulic motor and the winch drum, a switching valve is provided between the relief valve and the negative brake. A switching valve for communicating or shutting off the pilot pressure for releasing the function of the relief valve and the pilot pressure for opening the negative brake. Speed control system switch.