A winch control method

Abstract

The present invention provides a winch control method, which specifically includes the following steps: (1) a hydraulic pump station supplies oil to a winch control system, and the winch control system drives a motor to operate; (2) when the winch is on standby; (3) the oil circuit between a first control valve and a motor is disconnected; (4) the hydraulic oil in a first oil inlet pipeline flows into a first control end of a first center unloading valve; (5) the first center unloading valve is connected, and the hydraulic oil is unloaded through the first center unloading valve and flows back to the hydraulic pump station; (6) when the winch is started; (7) the first control valve is reversed; (8) a part of the hydraulic oil flows to the motor through the first control valve, and a part of the hydraulic oil flows to the second control end of the first center unloading valve through the P1 end or the T1 end of the first control valve, driving the first center unloading valve to be disconnected, and the hydraulic oil cannot flow back to the oil tank through the first center unloading valve; (9) the hydraulic oil enters the motor through the first control valve and drives the motor to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of winch control, and in particular to a winch control method. Background Art

[0002] Hydraulic winches are widely used in shipbuilding and other engineering industries. As the rated load and working speed requirements of winches continue to increase, the winch power is getting bigger and bigger, and the required flow rate is also getting bigger and bigger.

[0003] For example, Chinese patent application number 201310420155.6, published on December 25, 2013, discloses an energy-saving lifting system for a hydraulic crane. The system comprises a hydraulic oil tank, a hydraulic pump, a lifting motor, and a control valve. The hydraulic pump is driven by a prime mover, the hydraulic pump's inlet connected to the hydraulic oil tank, and the hydraulic pump's outlet connected to the lifting motor via a control valve. The hydraulic oil tank is connected to an accumulator hydraulic pump and a hydraulic pump, respectively. The accumulator hydraulic pump is connected to an unloading relief valve, which is connected to an accumulator and a hydraulically controlled one-way valve. The hydraulically controlled one-way valve is connected to a three-position, four-way valve. The hydraulic pump is connected to a relief valve and a three-position, four-way valve, respectively. The three-position, four-way valve is connected to the lifting motor via a shuttle valve and a two-way balancing valve. The lifting motor is equipped with a normally closed brake. This energy-saving lifting system for a hydraulic crane has a rational structure and reliable performance. It can recycle gravitational potential energy, reduce lifting power loss, and minimize wear on the accumulator hydraulic pump and the sheave.

[0004] This document can reduce the loss of lifting power. However, as the power of current winches is getting larger and larger, winches also require different loads. The hydraulic oil flow required by each winch motor is also different. In order to ensure that the winch can work even when it is at maximum load, a constant pressure variable pump is required. Such a variable pump usually does not stop supplying oil. When the hydraulic system of this document is applied to the current winch, it does not unload the hydraulic oil when the winch is on standby, which leads to increased energy consumption of the winch when it is on standby. Summary of the Invention

[0005] The present invention provides a winch control method, which ensures that the winch can run at high pressure and full load when it is started, and can realize low pressure circulation when the winch is on standby, thereby saving energy consumption, ensuring quantitative output of oil and facilitating pressurization operation.

[0006] To achieve the above object, the technical solution of the present invention is: a winch control method, which is implemented through an unloading system.

[0007] The specific steps include:

[0008] (1) The hydraulic pump station supplies oil to the winch control system, which drives the motor to operate.

[0009] (2) When the winch is on standby.

[0010] (3) The oil circuit between the first control valve and the motor is disconnected.

[0011] (4) The hydraulic oil in the first oil inlet pipeline flows into the first control end of the first mid-position unloading valve.

[0012] (5) The first center unloading valve is connected, and the hydraulic oil is unloaded through the first center unloading valve and flows back to the hydraulic pump station.

[0013] (6) When the winch is turned on.

[0014] (7) The first control valve is switched.

[0015] (8) Part of the hydraulic oil flows to the motor through the first control valve, and part of the hydraulic oil flows to the second control end of the first center unloading valve through the P1 end or T1 end of the first control valve to drive the first center unloading valve to disconnect. The hydraulic oil cannot flow back to the oil tank through the first center unloading valve.

[0016] (9) The hydraulic oil enters the motor through the first control valve and drives the motor to move.

[0017] (10) When the motor needs to be accelerated, the first manual reversing valve is driven to reverse, connecting the first oil inlet pipe and the motor, and the hydraulic oil flows into the motor through the first manual reversing valve to increase the pressure and speed.

[0018] The unloading system includes a hydraulic pump station and a winch control system. The hydraulic pump station supplies oil to the winch control system, and the winch control system drives the motor to rotate. The winch control system includes a first neutral unloading valve and a first control valve. The oil outlet of the hydraulic pump station is connected to the P end of the first control valve through a first oil outlet pipeline, and the T end of the first control valve is connected to the return oil port of the hydraulic pump station through a first return oil pipeline. The A end of the first control valve is connected to the first port of the motor, and the B end of the first control valve is connected to the second port of the motor.

[0019] A first center unloading valve is provided between the first oil inlet pipeline and the first oil return pipeline, the oil inlet end of the first center unloading valve is connected to the first oil inlet pipeline, the oil outlet end of the first center unloading valve is connected to the first oil return pipeline, and the first control end of the first center unloading valve is connected to the first oil inlet pipeline; the P1 end and the T1 end of the first control valve are connected to the second control end of the first center unloading valve, and when the first control valve is reversed, the P1 end and the P end are connected and the T end and the T1 end are connected, or the P1 end and the T end are connected and the P end and the T1 end are connected.

[0020] The hydraulic pump station includes an oil tank and a metering pump, wherein the oil inlet end of the metering pump is connected to the oil tank, the oil outlet end of the metering pump is connected to the first oil inlet pipeline through the oil outlet, and the first oil return pipeline is connected to the oil tank through the oil return port.

[0021] A first manual reversing valve is provided between the first oil inlet pipeline and the motor. The oil inlet end of the first manual reversing valve is connected to the hydraulic pump station through the first oil inlet pipeline, and the oil outlet end of the first manual reversing valve is connected to the motor.

[0022] The above structure supplies oil to the motor through the hydraulic pump station to drive the motor. When the winch is to be started, the first control valve is controlled to reverse, so that the P end of the first control valve is connected to the A end and the B end is connected to the T end to control the motor to rotate forward, or the P end of the first control valve is connected to the B end and the A end is connected to the T end to control the motor to reverse, thereby realizing the control of the motor. Since a first neutral unloading valve is provided between the first oil inlet pipeline and the first oil return pipeline, when the hydraulic pump station supplies oil, if the first control valve is not reversed, the hydraulic oil in the first oil inlet pipeline flows into the first control end of the first neutral unloading valve, so that the first neutral unloading valve is connected, and the hydraulic oil can be unloaded through the first neutral unloading valve and flow back to the hydraulic pump station; when the first control valve is reversed, the P1 end and the P end are connected and the T end and the T1 end are connected, or the P1 end and the T end are connected and the P end and the T1 end are connected, thereby making the hydraulic oil flowing from the hydraulic pump station to the P end of the first control valve can flow to the first neutral unloading valve through the P1 end and the T1 end. The second control end of the unloading valve, at this time, the hydraulic oil drives the first center unloading valve to disconnect, so that the hydraulic oil cannot be unloaded through the first center unloading valve, and the hydraulic oil can be supplied normally and drive the motor to rotate. Therefore, through the setting of the first center unloading valve, when the winch is on standby, the first center unloading valve is opened to allow the hydraulic oil to be unloaded through the first center unloading valve and flow back to the hydraulic pump station to realize low-pressure circulation, thereby ensuring that the energy consumption of the winch is not too large. When the winch needs to work, the hydraulic oil flowing to the first control valve controls the first center unloading valve to be disconnected, thereby allowing the hydraulic oil to flow normally to the motor for operation. At the same time, since the hydraulic pump station supplies oil through the metering pump, it can ensure a quantitative output of oil, so that the winch can operate stably. By setting the first manual reversing valve, when the winch needs to speed up, by controlling the first manual reversing valve, the hydraulic oil can flow to the motor through the first manual reversing valve, thereby realizing pressurization and speed-up of the motor.

[0023] Furthermore, a spring is provided on the second control end of the first mid-position unloading valve, and the spring pushes the internal oil circuit of the first mid-position unloading valve so that the oil inlet and oil outlet of the first mid-position unloading valve are disconnected.

[0024] The above arrangement overcomes the pressure of the hydraulic oil flowing into the first control end of the first center unloading valve by adding the hydraulic oil pressure of the spring to the second control end, thereby ensuring that the oil inlet and oil outlet ends of the first center unloading valve are disconnected, preventing the hydraulic oil from flowing back from the first center unloading valve to the oil tank when the oil circuit is working normally.

[0025] Furthermore, a first shuttle valve is provided between the P1 end and the T1 end of the first control valve and the second control end of the first mid-position unloading valve, the first port of the first shuttle valve is connected to the P1 end of the first control valve, the second port of the first shuttle valve is connected to the T1 end of the first control valve, and the third port of the first shuttle valve is connected to the second control end of the first mid-position unloading valve.

[0026] The above arrangement, by providing the first shuttle valve, prevents the hydraulic oils from the P1 end and the T1 end of the first control valve from flowing into the second control end of the first mid-position unloading valve from conflicting with each other.

[0027] Furthermore, a first overflow valve is provided between the second control end of the first mid-position unloading valve and the first oil return pipeline, the oil inlet end of the first overflow valve is connected to the second control end of the first mid-position unloading valve, and the oil outlet end of the first overflow valve is connected to the first oil return pipeline.

[0028] The above setting, by setting the first relief valve, when the winch is on standby, the first relief valve is normally open when power is off, so that the hydraulic oil is unloaded and the pressure is reduced through the first relief valve to realize low-pressure circulation of the hydraulic oil, thereby saving energy. When the winch is working, the first relief valve is powered on and closed, so that the hydraulic oil is pressurized and enters the motor to work.

[0029] Furthermore, a first pressure reducing valve is provided in the first oil inlet pipeline, the oil inlet end of the first pressure reducing valve is connected to the oil outlet of the hydraulic pump station through the first oil inlet pipeline, and the oil outlet end of the first pressure reducing valve is connected to the P end of the first control valve through the first oil inlet pipeline.

[0030] The above arrangement, through the arrangement of the first pressure reducing valve, enables the oil pressure of the oil circuit to be set, thereby facilitating the control of the winch.

[0031] Furthermore, the metering pump includes a first oil pump and a second oil pump, the oil inlet ends of the first oil pump and the second oil pump are connected to the oil tank, the oil outlet ends of the first oil pump and the second oil pump are connected to the first oil inlet pipe through the oil outlet, and the first oil return pipe is connected to the oil tank through the oil return port.

[0032] The above arrangement, by providing two oil pumps, enables the winch to operate at full load, and if one of the oil pumps fails to work, the other oil pump can drive the winch to operate at half load, preventing accidents caused by sudden stop of the winch.

[0033] Furthermore, a second pressure reducing valve is provided on the first oil inlet pipeline, the oil inlet end of the second pressure reducing valve is connected to the first oil inlet pipeline, and the oil outlet end of the second pressure reducing valve is connected to the oil inlet end of the first manual reversing valve.

[0034] The above arrangement, by providing the second pressure reducing valve, enables the pressure of the hydraulic oil delivered to the motor via the first manual reversing valve to be set, thereby facilitating control of the speed increase of the winch.

[0035] Furthermore, step (7) specifically includes:

[0036] (71) When it is necessary to control the motor to rotate forward, the P end of the first control valve is connected to the A end and the B end is connected to the T end, and the hydraulic oil flows into the first port of the motor through the A end of the first control valve and flows back to the oil tank from the second port through the B end of the first control valve; the P1 end of the first control valve is connected to the P end and the T end is connected to the T1 end.

[0037] (72) When it is necessary to control the motor to reverse, the P end of the first control valve is controlled to be connected to the B end and the A end is controlled to be connected to the T end, and the hydraulic oil flows into the second port of the motor through the B end of the first control valve and flows back to the oil tank from the first port through the A end of the first control valve; the P1 end of the first control valve is connected to the T end and the P end is connected to the T1 end.

[0038] The above arrangement facilitates the connection between the motor and the hydraulic pump station by reversing the first control valve, thereby achieving hydraulic control of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a hydraulic schematic diagram of the unloading system of the present invention.

[0040] Figure 2 It is a hydraulic schematic diagram of the winch control system of the present invention.

[0041] Figure 3 It is the workflow diagram of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] like Figures 1 to 2 As shown, an unloading system includes a hydraulic pump station 1 and a winch control system 2, wherein the hydraulic pump station 1 supplies oil to the winch control system 2, and the winch control system 2 drives the motor 3 to rotate. The winch control system 2 includes a first neutral unloading valve 21 and a first control valve 22. The oil outlet 11 of the hydraulic pump station 1 is connected to the P end of the first control valve 22 through a first oil outlet pipe 12, and the T end of the first control valve 22 is connected to the oil return port 14 of the hydraulic pump station 1 through a first oil return pipe 13. The A end of the first control valve 22 is connected to the first port A1 of the motor 3, and the B end of the first control valve 22 is connected to the second port B1 of the motor 3.

[0044] like Figure 2As shown, a first mid-position unloading valve 21 is provided between the first oil inlet pipeline 12 and the first oil return pipeline 13, the oil inlet end of the first mid-position unloading valve 21 is connected to the first oil inlet pipeline 12, the oil outlet end of the first mid-position unloading valve 21 is connected to the first oil return pipeline 13, and the first control end 211 of the first mid-position unloading valve 21 is connected to the first oil inlet pipeline 12; the P1 end and the T1 end of the first control valve 22 are connected to the second control end 212 of the first mid-position unloading valve 21, and when the first control valve 22 is switched, the P1 end and the P end are connected and the T end and the T1 end are connected, or the P1 end and the T end are connected and the P end and the T1 end are connected.

[0045] A spring 213 is also provided on the second control end 212 of the first center unloading valve 21. The spring 213 pushes the internal oil circuit of the first center unloading valve 21, disconnecting the oil inlet and outlet of the first center unloading valve 21. The spring 213 plus the hydraulic oil pressure at the second control end 212 overcomes the pressure of the hydraulic oil flowing into the first control end 211 of the first center unloading valve 21, thereby ensuring that the oil inlet and outlet of the first center unloading valve 21 are disconnected, preventing hydraulic oil from flowing back from the first center unloading valve 21 to the fuel tank when the oil circuit is functioning normally.

[0046] A first shuttle valve 23 is provided between the P1 and T1 ends of the first control valve 22 and the second control end 212 of the first center unloading valve 21. A first port 231 of the first shuttle valve 23 is connected to the P1 end of the first control valve 22, a second port 232 of the first shuttle valve 23 is connected to the T1 end of the first control valve 22, and a third port 233 of the first shuttle valve 23 is connected to the second control end 212 of the first center unloading valve 21. The provision of the first shuttle valve 23 prevents the hydraulic oil from the P1 and T1 ends of the first control valve 22 from conflicting with each other when flowing into the second control end 212 of the first center unloading valve 21.

[0047] A first relief valve 24 is provided between the second control end 212 of the first mid-position unloading valve 21 and the first oil return pipe 13. The oil inlet of the first relief valve 24 is connected to the second control end 212 of the first mid-position unloading valve 21, and the oil outlet of the first relief valve 24 is connected to the first oil return pipe 13. By providing the first relief valve 24, when the winch is in standby mode, the first relief valve 24 is de-energized and remains open, allowing the hydraulic oil to be unloaded and reduced in pressure through the first relief valve 24, achieving low-pressure circulation of the hydraulic oil and thus saving energy. When the winch is operating, the first relief valve 24 is energized and closed, allowing the hydraulic oil to be pressurized and enter the motor for operation.

[0048] A first pressure reducing valve 25 is also provided in the first oil inlet pipeline 12. The oil inlet end of the first pressure reducing valve 25 is connected to the oil outlet of the hydraulic pump station through the first oil inlet pipeline 12, and the oil outlet end of the first pressure reducing valve 25 is connected to the P end of the first control valve 22 through the first oil inlet pipeline 12. The provision of the first pressure reducing valve 25 allows the oil pressure of the oil circuit to be adjusted, facilitating the control of the winch.

[0049] like Figure 1 As shown, the hydraulic pump station 1 includes an oil tank 15, a first oil pump 16, and a second oil pump 17. The oil inlets of the first oil pump 116 and the second oil pump 17 are connected to the oil tank 15, and the oil outlets of the first oil pump 16 and the second oil pump 17 are connected to the first oil inlet pipe 12 through the oil outlet 11. The first oil return pipe 13 is connected to the oil tank 15 through the oil return port 14. The first oil pump 16 and the second oil pump 17 are fixed-displacement pumps. By providing fixed-displacement pumps, it is ensured that the winch can operate under the maximum load. By providing two oil pumps, the winch can be operated at full load. If one of the oil pumps fails and cannot work, the other oil pump can drive the winch to operate at half load, preventing the winch from stopping suddenly and causing an accident.

[0050] like Figure 1 As shown, a first manual reversing valve 18 is provided between the first oil inlet pipeline 12 and the motor 3. The oil inlet end of the first manual reversing valve 18 is connected to the hydraulic pump station 1 through the first oil inlet pipeline 12, and the oil outlet end of the first manual reversing valve 18 is connected to the motor 3. A second pressure reducing valve 19 is also provided on the first oil inlet pipeline 12. The oil inlet end of the second pressure reducing valve 19 is connected to the first oil inlet pipeline 12, and the oil outlet end of the second pressure reducing valve 19 is connected to the oil inlet end of the first manual reversing valve 18. The above configuration, by providing the second pressure reducing valve 19, allows the pressure of the hydraulic oil delivered to the motor 3 through the first manual reversing valve 18 to be adjusted, thereby facilitating the control of the speed increase of the winch.

[0051] like Figure 3 As shown, a winch control method includes the following specific steps:

[0052] The specific steps include:

[0053] (1) The hydraulic pump station supplies oil to the winch control system, which drives the motor to operate.

[0054] (2) When the winch is on standby.

[0055] (3) The oil circuit between the first control valve and the motor is disconnected.

[0056] (4) The hydraulic oil in the first oil inlet pipeline flows into the first control end of the first mid-position unloading valve.

[0057] (5) The first center unloading valve is connected, and the hydraulic oil is unloaded through the first center unloading valve and flows back to the hydraulic pump station.

[0058] (6) When the winch is turned on.

[0059] (7) The first control valve is switched.

[0060] (71) When it is necessary to control the motor to rotate forward, the P end of the first control valve is connected to the A end and the B end is connected to the T end, and the hydraulic oil flows into the first port of the motor through the A end of the first control valve and flows back to the oil tank from the second port through the B end of the first control valve; the P1 end of the first control valve is connected to the P end and the T end is connected to the T1 end.

[0061] (72) When it is necessary to control the motor to reverse, the P end of the first control valve is controlled to be connected to the B end and the A end is controlled to be connected to the T end, and the hydraulic oil flows into the second port of the motor through the B end of the first control valve and flows back to the oil tank from the first port through the A end of the first control valve; the P1 end of the first control valve is connected to the T end and the P end is connected to the T1 end.

[0062] (8) Part of the hydraulic oil flows to the motor through the first control valve, and part of the hydraulic oil flows to the second control end of the first center unloading valve through the P1 end or T1 end of the first control valve to drive the first center unloading valve to disconnect. The hydraulic oil cannot flow back to the oil tank through the first center unloading valve.

[0063] (9) The hydraulic oil enters the motor through the first control valve and drives the motor to move.

[0064] (10) When the motor needs to be accelerated, the first manual reversing valve is driven to reverse, connecting the first oil inlet pipe and the motor, and the hydraulic oil flows into the motor through the first manual reversing valve to increase the pressure and speed.

[0065] The working principle of the present invention is as follows: the motor 3 is driven by the hydraulic pump station 1 to supply oil to the motor 3. When the winch is to be started, the first control valve 22 is controlled to be reversed, so that the P end of the first control valve 22 is connected to the A end and the B end is connected to the T end to control the motor 3 to rotate forward, or the P end of the first control valve 22 is connected to the B end and the A end is connected to the T end to control the motor 3 to reverse, thereby realizing the control of the motor 3. Since the first mid-position unloading valve 21 is set between the first oil inlet pipeline 12 and the first oil return pipeline 13, when the hydraulic pump station 1 is supplying oil, If the first control valve 22 is not switched, the hydraulic oil in the first oil inlet pipe 12 flows into the first control end 211 of the first center unloading valve 21, so that the first center unloading valve 21 is connected, and the hydraulic oil can pass through the first center unloading valve 21 and then be unloaded through the first return pipe 13 and flow back to the oil tank 15; when the first control valve 22 is switched, the P1 end and the P end are connected and the T end and the T1 end are connected, or the P1 end and the T end are connected and the P end and the T1 end are connected, so that the hydraulic oil flowing from the hydraulic pump station 1 to the P end of the first control valve 22 can be The hydraulic oil can flow to the second control end 212 of the first center unloading valve 21 through the P1 end and the T1 end. At this time, the hydraulic oil drives the first center unloading valve 21 to be disconnected, so that the hydraulic oil cannot be unloaded through the first center unloading valve 21, and the hydraulic oil can be supplied normally and drive the motor 3 to rotate. Therefore, through the setting of the first center unloading valve 21, when the winch is on standby, the first center unloading valve 21 is opened to unload the hydraulic oil through the first center unloading valve 21 and flow back to the oil tank 15 to realize low-pressure circulation, thereby ensuring that the energy consumption of the winch will not be reduced. Too large, and when the winch needs to work, the first mid-position unloading valve 21 is disconnected by controlling the hydraulic oil flowing to the first control valve 22, so that the hydraulic oil can flow normally to the motor to operate. At the same time, since the hydraulic pump station supplies oil through the metering pump, the quantitative output oil volume can be ensured, so that the winch can operate stably. By setting the first manual reversing valve, when the winch needs to speed up, the first manual reversing valve is controlled so that the hydraulic oil can flow to the motor through the first manual reversing valve, thereby achieving pressurization and speed-up of the motor.

Claims

1. A winch control method implemented by an unloading system, wherein the unloading system includes a hydraulic pump station and a winch control system, wherein the hydraulic pump station supplies oil to the winch control system, and the winch control system drives a motor to rotate, characterized in that: The specific steps include: (1) The hydraulic pump station supplies oil to the winch control system, which drives the motor to operate; (2) When the winch is on standby; (3) The oil circuit between the first control valve and the motor is disconnected; (4) The hydraulic oil in the first oil inlet pipeline flows into the first control end of the first mid-position unloading valve; (5) The first center unloading valve is connected, and the hydraulic oil is unloaded through the first center unloading valve and flows back to the hydraulic pump station; (6) When the winch is turned on; (7) The first control valve reversing includes: (71) When the motor needs to be controlled to rotate forward, the P end of the first control valve is connected to the A end and the B end is connected to the T end, and the hydraulic oil flows into the first port of the motor through the A end of the first control valve and flows back to the oil tank from the second port through the B end of the first control valve; the P1 end of the first control valve is connected to the P end and the T end is connected to the T1 end; (72) When the motor needs to be reversed, the P end of the first control valve is connected to the B end and the A end is connected to the T end, and the hydraulic oil flows into the second port of the motor through the B end of the first control valve and flows back to the oil tank from the first port through the A end of the first control valve; the P1 end of the first control valve is connected to the T end and the P end is connected to the T1 end; (8) Part of the hydraulic oil flows to the motor through the first control valve, and part of the hydraulic oil flows to the second control end of the first center unloading valve through the P1 end or T1 end of the first control valve to drive the first center unloading valve to open. The hydraulic oil cannot flow back to the oil tank through the first center unloading valve; (9) The hydraulic oil enters the motor through the first control valve and drives the motor to move; (10) When the motor needs to be accelerated, the first manual reversing valve is driven to reverse, connecting the first oil inlet pipe and the motor, and the hydraulic oil flows into the motor through the first manual reversing valve to increase pressure and speed; The winch control system includes a first mid-position unloading valve and a first control valve, the oil outlet of the hydraulic pump station is connected to the P end of the first control valve through a first oil outlet pipeline, the T end of the first control valve is connected to the oil return port of the hydraulic pump station through a first return oil pipeline, the A end of the first control valve is connected to the first port of the motor, and the B end of the first control valve is connected to the second port of the motor; a first shuttle valve is provided between the P1 end and the T1 end of the first control valve and the second control end of the first mid-position unloading valve, the first port of the first shuttle valve is connected to the P1 end of the first control valve, the second port of the first shuttle valve is connected to the T1 end of the first control valve, and the third port of the first shuttle valve is connected to the second control end of the first mid-position unloading valve; A first center unloading valve is provided between the first oil inlet pipeline and the first oil return pipeline. The oil inlet end of the first center unloading valve is connected to the first oil inlet pipeline, the oil outlet end of the first center unloading valve is connected to the first oil return pipeline, and the first control end of the first center unloading valve is connected to the first oil inlet pipeline; the P1 end and the T1 end of the first control valve are connected to the second control end of the first center unloading valve. When the first control valve is switched, the P1 end and the P end are connected and the T end and the T1 end are connected, or the P1 end and the T end are connected and the P end and the T1 end are connected; a spring is also provided on the second control end of the first center unloading valve, which pushes the internal oil circuit of the first center unloading valve to disconnect the oil inlet end and the oil outlet end of the first center unloading valve; The hydraulic pump station includes an oil tank and a metering pump, wherein the oil inlet end of the metering pump is connected to the oil tank, the oil outlet end of the metering pump is connected to the first oil inlet pipe through the oil outlet, and the first oil return pipe is connected to the oil tank through the oil return port; A first manual reversing valve is provided between the first oil inlet pipeline and the motor. The oil inlet end of the first manual reversing valve is connected to the hydraulic pump station through the first oil inlet pipeline, and the oil outlet end of the first manual reversing valve is connected to the motor.

2. A winch control method according to claim 1, characterized in that: A first overflow valve is provided between the second control end of the first mid-position unloading valve and the first oil return pipeline, the oil inlet end of the first overflow valve is connected to the second control end of the first mid-position unloading valve, and the oil outlet end of the first overflow valve is connected to the first oil return pipeline.

3. A winch control method according to claim 1, characterized in that: A first pressure reducing valve is also provided in the first oil inlet pipeline. The oil inlet end of the first pressure reducing valve is connected to the oil outlet of the hydraulic pump station through the first oil inlet pipeline, and the oil outlet end of the first pressure reducing valve is connected to the P end of the first control valve through the first oil inlet pipeline.

4. A winch control method according to claim 1, characterized in that: The metering pump includes a first oil pump and a second oil pump, the oil inlet ends of the first oil pump and the second oil pump are connected to the oil tank, the oil outlet ends of the first oil pump and the second oil pump are connected to the first oil inlet pipeline through the oil outlet, and the first oil return pipeline is connected to the oil tank through the oil return port.

5. A winch control method according to claim 4, characterized in that: A second pressure reducing valve is further provided on the first oil inlet pipeline, the oil inlet end of the second pressure reducing valve is connected to the first oil inlet pipeline, and the oil outlet end of the second pressure reducing valve is connected to the oil inlet end of the first manual reversing valve.

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