CN114212714A

CN114212714A - Hydraulic system of crane

Info

Publication number: CN114212714A
Application number: CN202111321344.9A
Authority: CN
Inventors: 安万平; 郭安罗; 谷文平; 王良伟; 宋兴祥; 王海江; 包宗斌; 赵军勇
Original assignee: South China Marine Machinery Co Ltd
Current assignee: South China Marine Machinery Co Ltd
Priority date: 2021-11-09
Filing date: 2021-11-09
Publication date: 2022-03-22
Anticipated expiration: 2041-11-09
Also published as: CN114212714B

Abstract

The invention provides a hydraulic system of a crane; the device comprises a lifting system, a rotating system, a variable amplitude system, a pump station oil tank and a multi-way valve; the pump station oil tank is communicated with the lifting system, the rotating system, the amplitude varying system and the multi-way valve; the pump station oil tank supplies oil to the multi-way valve, the amplitude varying system, the lifting system and the rotating system respectively; a lifting emergency descending oil way in the lifting system is connected with a lifting ascending oil way and a lifting descending oil way and is connected with a lifting emergency oil way; hydraulic oil circularly flows at two ends of the lifting variable motor through a lifting ascending oil way, a lifting emergency descending oil way and a lifting descending oil way; the lifting winch stably descends under the action of load; the first amplitude-variable communicating oil way in the amplitude-variable system is communicated with the first amplitude-variable ascending oil way and the second amplitude-variable ascending oil way; the second amplitude-variable communicating oil way is communicated with the first amplitude-variable descending oil way and the second amplitude-variable descending oil way; the first variable amplitude hydraulic motor and the second variable amplitude hydraulic motor synchronously rotate; and the amplitude-variable winch stably acts.

Description

Hydraulic system of crane

Technical Field

The invention relates to the field of cranes, in particular to a hydraulic system of a crane.

Background

The marine crane is a special crane for carrying out transportation operation in the marine environment, and is mainly used for important tasks of transportation and transfer of goods among ships, marine supply, throwing and recovering of underwater operation equipment and the like.

In chinese application No. 201811289896.4; the patent document with publication number 2020.5.8 discloses a crane hydraulic system and a working method; it discloses a hoisting system and a luffing system; the amplitude varying system is connected with one end of a first amplitude varying hydraulic motor through an amplitude varying ascending oil supply pipeline; the other variable-amplitude ascending oil supply pipeline is connected with one end of a second variable-amplitude hydraulic motor; is connected with the other end of the first variable-amplitude hydraulic motor through a variable-amplitude descending oil supply pipeline; the other amplitude-variable descending oil supply pipeline is connected with one end of a second amplitude-variable hydraulic motor; but the two amplitude-variable ascending oil supply pipelines and the two amplitude-variable descending oil supply pipelines are not communicated; when the flow of hydraulic oil entering a pipeline is large; when the flow of the hydraulic oil entering the other pipeline is small, the pressure born by the two pipelines is inconsistent; meanwhile, the two pipelines have the condition of inconsistent hydraulic oil flow; the flow of hydraulic oil passing through the first variable amplitude balance valve and the second variable amplitude balance valve respectively is inconsistent; the flow of hydraulic oil entering the first variable amplitude hydraulic motor and the flow of hydraulic oil entering the second variable amplitude hydraulic motor cannot be kept consistent; so that the first variable amplitude hydraulic motor and the second variable amplitude hydraulic motor can not synchronously rotate; hydraulic system pressure imbalance is easily created. The speed of the lifting system can not be adjusted when the lifting system carries out emergency descending action; the stable descent cannot be performed according to the load of the hoisting winch.

Disclosure of Invention

The invention provides a hydraulic system of a crane, which controls the descending speed of a lifting device of a lifting system during emergency operation; and the flow of hydraulic oil of the first amplitude-variable hydraulic motor and the second amplitude-variable hydraulic motor of the amplitude-variable system is kept consistent.

In order to achieve the purpose, the technical scheme of the invention is as follows: a hydraulic system of a crane; the device comprises a lifting system, a rotating system, a variable amplitude system, a pump station oil tank and a multi-way valve; the pump station oil tank is communicated with the lifting system, the rotating system, the amplitude varying system and the multi-way valve; the pump station oil tank supplies oil to the multi-way valve, the amplitude varying system, the lifting system and the rotating system respectively; and a manual power device is connected between the pump station oil tank and the lifting system, between the pump station oil tank and the rotary system and between the pump station oil tank and the amplitude varying system.

The lifting system comprises a lifting winch, a lifting variable motor, a lifting balance valve, a normally closed ball valve I, a normally closed ball valve II, a normally closed adjustable throttle valve and a normally open ball valve; one end of the lifting variable motor is connected with a lifting oil way; a lifting oil circuit is connected with a control oil port WA; a lifting balance valve is connected to the lifting oil path; the other end of the lifting variable motor is connected with a lifting descending oil way; the lifting and descending oil way is connected with a control oil port WB; the lifting and descending oil way is connected with a normally open ball valve; a lifting emergency descending oil way is connected between the lifting ascending oil way and the lifting descending oil way; one end of the lifting emergency descending oil way is connected between the lifting balance valve and the lifting variable motor; the other end of the lifting emergency descending oil way is arranged between the lifting variable motor and the normally-open ball valve; a normally closed adjustable throttle valve and a normally closed ball valve II are sequentially connected to the lifting emergency descending oil circuit; a lifting emergency oil way is connected between the normally closed ball valve II and the lifting emergency descending oil way; the lifting emergency oil way is connected with an emergency oil port BR 1; the oil drain port of the lifting variable motor is connected with a lifting oil return path; the lifting oil return oil path is connected with an oil return port WL; the power output end of the lifting variable motor is connected with a lifting winch; the manual power device is connected with an emergency oil port BR 1.

The amplitude varying system comprises a first amplitude varying hydraulic motor, a second amplitude varying hydraulic motor, a first amplitude varying balance valve, a second amplitude varying balance valve, an amplitude varying winch, an amplitude varying brake mechanism, a first amplitude varying reversing valve and an amplitude varying shuttle valve; the power output end of the first variable-amplitude hydraulic motor and the power output end of the second variable-amplitude hydraulic motor are respectively connected with a variable-amplitude winch; one end of the first variable amplitude hydraulic motor is connected with a first variable amplitude ascending oil way; the first variable-amplitude ascending oil way is connected with a control oil port BA 1; the other end of the first variable amplitude hydraulic motor is connected with a first variable amplitude descending oil way; the first amplitude-variable descending oil way is connected with a control oil port BB 1; the first amplitude-variable ascending oil way is connected with a first amplitude-variable balance valve; one end of the second variable-amplitude hydraulic motor is connected with a second variable-amplitude ascending oil way; the second variable-amplitude ascending oil way is connected with a control oil port BA 2; the other end of the second variable-amplitude hydraulic motor is connected with a second variable-amplitude descending oil way; the second amplitude-variable descending oil way is connected with a control oil port BB 2; a second variable-amplitude ascending oil path is connected with a second variable-amplitude balance valve; a first variable-amplitude oil-communicating passage is connected between the first variable-amplitude oil-rising passage and the second variable-amplitude oil-rising passage; the flow of the hydraulic oil in the first variable-amplitude ascending oil way is consistent with that of the hydraulic oil in the second variable-amplitude ascending oil way; a second variable-amplitude descending oil way is connected between the first variable-amplitude descending oil way and the second variable-amplitude descending oil way; the flow of the hydraulic oil in the first amplitude-variable descending oil way is consistent with that of the hydraulic oil in the second amplitude-variable descending oil way.

The rotary system comprises a rotary bidirectional balance valve, a rotary hydraulic motor, a rotary one-way throttle valve, a rotary hydraulic control reversing valve and a rotary hydraulic brake; the rotary bidirectional balance valve comprises a rotary first balance valve, a rotary first balance valve and a rotary shuttle valve; one end of the rotary hydraulic motor is connected with a rotary first oil way; the first rotary oil way is connected with a control oil port S01; the other end of the rotary hydraulic motor is connected with a rotary second oil way; the first rotary oil way is connected with a control oil port S02; the oil drain port of the rotary hydraulic motor is connected with a rotary oil drain oil way; the rotary oil drainage oil path is connected with a control oil port SL; the rotary hydraulic motor is also connected with a rotary hydraulic brake; the rotary first balance valve is arranged on the rotary first oil path; the rotary second balance valve is arranged on the rotary second oil path; one end of the rotary shuttle valve is connected between the control oil port S01 and the rotary first balance valve; the other end of the rotary shuttle valve is connected between the control oil port S02 and the rotary second balance valve; the output end of the rotary shuttle valve is connected with the signal end of the rotary hydraulic control balance valve; one end of the rotary hydraulic control reversing valve is connected with the rotary oil drainage oil path; the other end of the rotary hydraulic control reversing valve is connected with a rotary emergency oil port BR3 and a rotary hydraulic brake; the rotary one-way throttle valve is connected between the rotary hydraulic control reversing valve and the rotary hydraulic brake.

According to the arrangement, oil is supplied through the oil tank of the pump station; controlling a lifting system, a rotating system and a variable amplitude system through a multi-way valve; when the lifting system is controlled, hydraulic oil output by a pump station oil tank enters the lifting system; hydraulic oil flows in from a control oil port WA; hydraulic oil enters a lifting variable motor after flowing through a lifting balance valve; then flows out from a control oil port WB; realizing the lifting of a lifting winch; hydraulic oil flows in from the control oil port WB; hydraulic oil enters a lifting variable motor; then flows out from a control port WA; and the descending of the hoisting winch is realized.

When the crane loses power or the power device fails, emergency operation is required, and a lifting emergency descending oil way is arranged; closing the normally open ball valve; opening the normally closed ball valve I and the normally closed ball valve II; oil supply is carried out on the emergency oil port BR1 through a manual power device; hydraulic oil flows in from an emergency oil port BR 1; flows through a lifting emergency oil way, a lifting emergency descending oil way and a lifting descending oil way; hydraulic oil enters a lifting variable motor; oil pressure exists between the lifting variable motor and the lifting balance valve; at the moment, the lifting variable motor does not act; opening a normally closed adjustable throttle valve; hydraulic oil flows through a lifting emergency descending oil way and a lifting descending oil way from one end of the lifting variable motor; then flows to the other end of the lifting variable motor; thus, under the load action of the object connected with the hoisting winch; the hoisting winch performs a lowering action. The opening degree of the normally closed adjustable throttle valve is adjusted; changing the flow rate of hydraulic oil passing through the normally closed adjustable throttle valve; further controlling the speed of the descending action; the lifting system adjusts the descending speed through the opening of the normally closed adjustable throttle valve during emergency operation.

When the amplitude varying system is controlled, hydraulic oil output by a pump station oil tank enters the amplitude varying system; a first amplitude-variable communicating oil way is arranged; hydraulic oil in the first amplitude-variable ascending oil way flows into the second amplitude-variable ascending oil way; hydraulic oil in the second amplitude-variable ascending oil way flows into the first amplitude-variable ascending oil way; the flow of the hydraulic oil in the first variable-amplitude ascending oil way is consistent with that of the hydraulic oil in the second variable-amplitude ascending oil way; a second amplitude-variable communicating oil way is arranged; hydraulic oil in the first amplitude-variable descending oil way flows into the second amplitude-variable descending oil way; hydraulic oil in the second amplitude-variable descending oil way flows into the first amplitude-variable descending oil way; the flow of the hydraulic oil in the first amplitude-variable descending oil way is consistent with that of the hydraulic oil in the second amplitude-variable descending oil way; thus, the pressure born by the first amplitude ascending oil circuit and the second amplitude ascending oil circuit is consistent; the pressure born by the first amplitude-variable descending oil circuit and the second amplitude-variable descending oil circuit is consistent; meanwhile, the flow rates of hydraulic oil between the two amplitude ascending oil ways and between the two amplitude ascending oil ways are consistent; the flow of hydraulic oil is consistent through the first variable amplitude balance valve and the second balance valve; the flow rates of the hydraulic oil respectively entering the first variable amplitude hydraulic motor and the second variable amplitude hydraulic motor are the same; so that the first variable amplitude hydraulic motor and the second variable amplitude hydraulic motor can synchronously rotate; so that the amplitude-variable winch can stably act; while reducing the risk of pressure imbalance in the hydraulic system.

When the rotary system is controlled, hydraulic oil output by a pump station oil tank enters the rotary system; hydraulic oil flows into the rotary first oil passage from the control oil port S01; hydraulic oil flows into the rotary first balance valve; hydraulic oil flows to a signal end of the rotary hydraulic control reversing valve; reversing by a rotary hydraulic control reversing valve; hydraulic oil entering from a rotary emergency oil port BR3 opens a rotary hydraulic brake; meanwhile, hydraulic oil in the first rotary oil way flows to the rotary hydraulic motor; then flows out of the rotary second oil way; driving the rotary hydraulic motor to rotate in one direction; when the hydraulic oil flows into the rotary second oil passage from the control oil port S02; hydraulic oil flows into the rotary second balance valve; hydraulic oil flows to a signal end of the rotary hydraulic control reversing valve; reversing by a rotary hydraulic control reversing valve; hydraulic oil entering from a rotary emergency oil port BR3 opens a rotary hydraulic brake; meanwhile, hydraulic oil in the second rotary oil way flows to the rotary hydraulic motor; then flows out of the first rotary oil way; the rotary hydraulic motor is driven to rotate in the other direction.

Furthermore, the lifting system also comprises a lifting hydraulic brake, a lifting shuttle valve I, a lifting reversing valve and a lifting limiting reversing valve; the lifting hydraulic brake is connected with the output end of the lifting variable motor in a clamping manner; the output end of the lifting shuttle valve I is connected with the signal end of the lifting reversing valve and one end of the lifting reversing valve; one end of the lifting reversing valve is also connected with a lifting hydraulic brake; the other end of the lifting reversing valve is connected with a lifting oil return path; one input end of the lifting shuttle valve I is connected with one end of the lifting limiting reversing valve; the other end of the lifting limiting reversing valve is connected with a lifting oil way and an oil tank; the other input end of the first lifting shuttle valve is connected with a lifting descending oil way.

The above setting is carried out; when the lifting winch is normally lifted, hydraulic oil flows in from a control oil port WA; hydraulic oil enters a lifting variable motor after flowing through a lifting balance valve; then flows out from a control oil port WB; hydraulic oil simultaneously flows through the first lifting shuttle valve; the output end of the lifting shuttle valve I outputs signal oil; the signal oil flows to the lifting reversing valve; reversing the lifting reversing valve; then hydraulic oil flows through a lifting reversing valve from the output end of the first lifting shuttle valve to enter a lifting hydraulic brake, and the brake is opened; enabling the lifting winch to perform lifting action; when the lifting winch normally descends; hydraulic oil flows in from the control oil port WB; hydraulic oil enters a lifting variable motor; then flows out from a control port WA; hydraulic oil simultaneously flows through the first lifting shuttle valve; the output end of the lifting shuttle valve I outputs signal oil; the signal oil flows to the lifting reversing valve; reversing the lifting reversing valve; then hydraulic oil enters a lifting hydraulic brake from the output end of the lifting shuttle valve I through a lifting reversing valve, and the brake is opened; so that the hoisting winch performs a lowering action. When the lifting device is normally used, the lifting or descending speed is adjusted according to the load of a lifted object.

Furthermore, the lifting balance valve comprises a lifting one-way valve and a lifting overflow valve; an oil inlet of the lifting overflow valve is connected with one end of a lifting variable motor; an oil outlet of the lifting overflow valve is connected with a control oil port WA; a control oil port of the lifting overflow valve is connected with a lifting descending oil way; an oil inlet of the lifting one-way valve is connected with an oil outlet of the lifting overflow valve; and a lifting one-way throttle valve is connected between a control oil port of the lifting overflow valve and the lifting descending oil way.

Furthermore, the lifting system also comprises a second lifting shuttle valve and a lifting pressure reducing valve; the lifting variable motor is provided with a variable mechanism; one input end of the lifting shuttle valve II is connected with a control oil port WA; the other input end of the lifting shuttle valve II is connected with a control oil port WB; the output end of the second lifting shuttle valve is connected with the oil inlet of the lifting pressure reducing valve; an oil outlet of the lifting pressure reducing valve is connected with a variable mechanism; the oil drain port of the lifting pressure reducing valve is connected with the oil tank.

The above setting is carried out; by setting a variable mechanism; the oil pressure can be adjusted according to the load of an object connected with the hoisting winch; so that when the load is large; the lifting and descending speeds become slow; when the load is small; the lifting and descending speed becomes fast; meanwhile, a lifting pressure reducing valve is arranged; the oil pressure output by the lifting pressure reducing valve is kept in a certain range; the variable mechanism is protected.

Furthermore, the amplitude-variable brake mechanism comprises a first amplitude-variable hydraulic brake and a second amplitude-variable hydraulic brake; the first amplitude-variable hydraulic brake clamps the power output end of the first amplitude-variable hydraulic motor; the second variable amplitude hydraulic brake clamps the power output end of the second variable amplitude hydraulic motor; the first amplitude-variable hydraulic brake and the second amplitude-variable hydraulic brake are both connected with one end of the first amplitude-variable reversing valve; the other end of the first variable amplitude reversing valve is connected with an emergency oil way; the emergency oil way is connected with a control oil port BR 2; the signal end of the first amplitude-changing reversing valve is connected with the output end of the amplitude-changing shuttle valve; one input end of the amplitude-variable shuttle valve is connected with the first amplitude-variable ascending oil way; the other input end of the amplitude-variable shuttle valve is connected with the first amplitude-variable descending oil way.

The above setting is carried out; when the amplitude-variable winch carries out lifting action; hydraulic oil is input from the first amplitude-variable ascending oil path and is input into a signal end of the first amplitude-variable reversing valve; reversing the first variable amplitude reversing valve; hydraulic oil entering from the emergency oil way flows into a variable amplitude hydraulic brake and a second variable amplitude hydraulic brake to open the brake; the first variable amplitude hydraulic motor and the second variable amplitude hydraulic motor synchronously rotate; when the amplitude-variable winch descends; hydraulic oil is input into a signal end of the first amplitude-variable reversing valve from the first amplitude-variable descending oil way; reversing the first variable amplitude reversing valve; hydraulic oil entering from the emergency oil way flows into a variable amplitude hydraulic brake and a second variable amplitude hydraulic brake to open the brake; the first amplitude-variable hydraulic motor and the second amplitude-variable hydraulic motor rotate synchronously.

Furthermore, the amplitude varying system also comprises an amplitude varying upper limiting reversing valve and an amplitude varying lower limiting reversing valve; the amplitude variation upper limiting reversing valve is connected between the amplitude variation shuttle valve and the first amplitude variation ascending oil way; the amplitude-variable lower limiting reversing valve is connected between the amplitude-variable shuttle valve and the first amplitude-variable descending oil way. Therefore, the lifting and the descending of the amplitude-variable winch can be respectively limited.

Furthermore, an oil drain port of the first variable amplitude hydraulic motor, an oil drain port of the second variable amplitude hydraulic motor, one end of the first variable amplitude reversing valve, one end of the variable amplitude upper limiting reversing valve and one end of the variable amplitude lower limiting reversing valve are connected with an oil return line; the oil return oil way is connected with a control oil port BL.

Further, the first amplitude-variable balance valve comprises a first amplitude-variable one-way valve and a first amplitude-variable overflow valve; an oil inlet of the first variable amplitude overflow valve is connected with one end of the first variable amplitude hydraulic motor; an oil outlet of the first variable amplitude overflow valve is connected with a control oil port BA 1; a control oil port of the first variable-amplitude overflow valve is connected with the second variable-amplitude descending oil way; an oil inlet of the first variable amplitude one-way valve is connected with an oil outlet of the first variable amplitude overflow valve; an oil outlet of the first variable amplitude one-way valve is connected with an oil inlet of the first variable amplitude overflow valve; the second amplitude-variable balance valve comprises a second amplitude-variable one-way valve and a second amplitude-variable overflow valve; an oil inlet of the second variable amplitude overflow valve is connected with one end of the second variable amplitude hydraulic motor; an oil outlet of the second variable-amplitude overflow valve is connected with a control oil port BA 2; a control oil port of the second variable-amplitude overflow valve is connected with the second variable-amplitude descending oil way; an oil inlet of the second variable amplitude one-way valve is connected with an oil outlet of the second variable amplitude overflow valve; an oil outlet of the second variable amplitude one-way valve is connected with an oil inlet of the second variable amplitude overflow valve.

Drawings

FIG. 1 is a schematic diagram of the present invention.

Fig. 2 is a hydraulic schematic diagram of a lifting system of the present invention.

FIG. 3 is a hydraulic schematic of a luffing system according to the present invention.

Fig. 4 is a hydraulic schematic of the swing system of the present invention.

Detailed Description

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

As shown in fig. 1-4; a hydraulic system of a crane; the device comprises a lifting system 1, a rotary system 2, a variable amplitude system 3, a pump station oil tank 4 and a multi-way valve 5; the pump station oil tank is communicated with the lifting system, the rotating system, the amplitude varying system and the multi-way valve; the pump station oil tank supplies oil to the multi-way valve, the amplitude varying system, the lifting system and the rotating system respectively; and a manual power device 6 is connected between the pump station oil tank 4 and the lifting system 1, between the rotary system 2 and between the pump station oil tank and the amplitude varying system 3. In this embodiment, the manual power device 6 is a hand pump.

The lifting system comprises a lifting winch 11, a lifting hydraulic brake 12, a lifting variable motor 13, a lifting shuttle valve I14, a lifting shuttle valve II 15, a lifting balance valve 16, a lifting reversing valve 17, a lifting limiting reversing valve 18, a lifting pressure reducing valve 191, a normally closed ball valve I192, a normally closed ball valve II 193, a normally closed adjustable throttle valve 194, a normally open ball valve 195 and a lifting one-way throttle valve 196.

One end of the lifting variable motor 13 is connected with a lifting oil-lifting circuit 101; the lifting oil-lifting circuit 101 is connected with a control oil port WA; a lifting balance valve 16 is connected to the lifting oil path 101; the control oil port WA is connected with an oil inlet of the lifting balance valve 16; an oil outlet of the lifting balance valve 16 is connected with one end of a lifting variable motor 13; the other end of the lifting variable motor 13 is connected with a lifting descending oil way 102; the lifting and descending oil way 102 is connected with a control oil port WB; the control oil port of the lifting balance valve 16 is connected with a lifting descending oil path 102. The oil drain port of the lifting variable motor 13 is connected with a lifting oil return path 103; the lifting oil return oil path 103 is connected with an oil return port WL; the power output end of the lifting variable motor 13 is connected with a lifting winch 11, and a lifting hydraulic brake 12 is connected with the output end of the lifting variable motor 13 in a clamping manner. And the control oil port WA, the control oil port WB and the control oil port WL are connected with the pump station oil tank.

In this embodiment, the lifting directional control valve is a two-position three-way hydraulic control directional control valve. The output end of the lifting shuttle valve I14 is connected with the signal end of the lifting reversing valve 17 and the port A2 of the lifting reversing valve 17; the port B2 of the lifting reversing valve 17 is connected with a lifting hydraulic brake 12; another P2 port of the lifting reversing valve 17 is connected with a lifting oil return path; an input end of the lifting shuttle valve I14 is connected with a port B1 of the lifting limit reversing valve 18; a P1 port of the lifting limit reversing valve 18 is connected with a control oil port WA; the T1 port of the lifting limiting reversing valve 18 is connected with a pump station oil tank; the port a1 of the lift limit switching valve 18 is closed. The other input end of the first lifting shuttle valve 14 is connected with a normally open ball valve 195.

In the present embodiment, the lift limiting directional control valve 18 is a two-position four-way mechanical directional control valve. When the hydraulic pump rises, the hydraulic oil flowing from the control oil port WA flows from the P1 to the B1 port; then flows into a lifting shuttle valve I14; when the lifting limit reversing valve 18 reaches the limit reversing; hydraulic oil flows from P1 to A1; the A1 port is cut off; at the moment, hydraulic oil does not flow into the lifting shuttle valve I14; and then the lifting hydraulic brake 12 is reset to brake the lifting winch 11. The lifting hydraulic brake 12 is a normally closed brake; the lifting hydraulic brake 12 is prior art and will not be described herein in detail.

The normally open ball valve 195 is connected between the lifting variable motor 13 and the control oil port WB; a lifting emergency descending oil way 104 is connected between the lifting ascending oil way 101 and the lifting descending oil way 102; the lifting emergency descending oil way 104 is connected with a lifting emergency oil way 105; one end of the lifting emergency descending oil line 104 is connected between the lifting balance valve 16 and the lifting variable motor 13; the other end of the lifting emergency descending oil line 104 is between the lifting variable motor 13 and the normally-open ball valve 195. The lifting emergency oil way 105 is connected with an emergency oil port BR 1; the lifting emergency descending oil way 104 is sequentially provided with a normally closed adjustable throttle valve 194 and a normally closed ball valve II 193. One end of the lifting emergency oil path 105 is connected between the normally closed ball valve II 193 and the lifting descending oil path 102.

The lifting variable motor 13 is provided with a variable mechanism 131; one input end of the second lifting shuttle valve 15 is connected with the control oil port WA; the other input end of the second lifting shuttle valve 15 is connected with a control oil port WB; the output end of the second lifting shuttle valve 15 is connected with the oil inlet of the lifting pressure reducing valve 191; an oil outlet of the lifting pressure reducing valve 191 is connected with the variable mechanism 131; and an oil drainage port of the lifting pressure reducing valve 191 is connected with an oil tank of the pump station. The variable mechanism 131 is prior art; in chinese application No. 201420083556.7; patent document No. 2014.2.26; the technical features and the working principle of the variable mechanism 131 are disclosed; and will not be described herein in a repeated manner. By providing a variable mechanism 131; the oil pressure can be adjusted according to the load of the object connected with the hoisting winch 11; so that when the load is large; the lifting and descending speeds become slow; when the load is small; the lifting and descending speed becomes fast; meanwhile, a lifting pressure reducing valve 191 is arranged; the oil pressure output by the lifting pressure reducing valve 191 is kept in a certain range; the variable mechanism 131 is protected.

The lifting balance valve 16 comprises a lifting one-way valve 161 and a lifting overflow valve 162; an oil inlet of the lifting overflow valve 162 is connected with one end of the lifting variable motor 13; an oil outlet of the lifting overflow valve 162 is connected with a control oil port WA; a control oil port of the lifting overflow valve 162 is connected with one end of a lifting one-way throttle valve 196; the other end of the lifting one-way throttle valve 196 is connected with a lifting descending oil way; the oil inlet of the lifting one-way valve 161 is connected with the oil outlet of the lifting overflow valve 162.

Pressure measuring points 197 are arranged between the lifting hydraulic brake 12 and one end of the lifting reversing valve 17, between one end of the lifting limiting reversing valve 18 and the oil inlet and the control oil port WA of the lifting balance valve 16, and between one end of the lifting variable motor 13 and the normally open ball valve 195.

When the lifting winch is normally lifted, hydraulic oil is input into a lifting system from an oil tank of a pump station; hydraulic oil flows in from a control oil port WA; hydraulic oil enters the lifting variable motor 13 after flowing through the lifting balance valve 16; then flows out from a control oil port WB; hydraulic oil simultaneously flows through the first lifting shuttle valve 14; the output end of the lifting shuttle valve I14 outputs signal oil; the signal oil flows to the lifting reversing valve 17; reversing the lifting reversing valve 17; then, hydraulic oil flows from the output end of the first lifting shuttle valve 14 through the lifting reversing valve 17 to enter the lifting hydraulic brake 12, and the brake is opened; so that the hoisting winch 11 performs a hoisting action; when the lifting winch normally descends; hydraulic oil flows in from the control oil port WB; hydraulic oil enters the lifting variable motor 13; then flows out from a control port WA; hydraulic oil simultaneously flows through the first lifting shuttle valve 14; the output end of the lifting shuttle valve I14 outputs signal oil; the signal oil flows to the lifting reversing valve 17; reversing the lifting reversing valve 17; then, hydraulic oil flows from the output end of the first lifting shuttle valve 14 through the lifting reversing valve 17 to enter the lifting hydraulic brake 12, and the brake is opened; so that the hoisting winch 11 performs a lowering action.

When the crane loses power or the power device fails, emergency operation is required, and the normally open ball valve 195 is closed; opening a first normally closed ball valve 192 and a second normally closed ball valve 193; hydraulic oil flows in from an emergency oil port BR 1; hydraulic oil flows in through the first lifting shuttle valve 14; the output end of the lifting shuttle valve I14 outputs signal oil; the signal oil flows to the lifting reversing valve 17; reversing the lifting reversing valve 17; then, hydraulic oil flows from the output end of the first lifting shuttle valve 14 through the lifting reversing valve 17 to enter the lifting hydraulic brake 12, and the brake is opened; hydraulic oil simultaneously enters the lifting variable motor 13; oil pressure exists between the lifting variable motor 13 and the lifting balance valve 16; at this time, the lifting variable motor 13 does not act; opening the normally closed adjustable flow valve 194; hydraulic oil flows from one end of the lifting variable motor 13 through the normally closed adjustable throttle valve 194 and the normally closed ball valve II 193; then flows to the other end of the lifting variable motor 13; thus under the load of the object to which the hoisting winch 11 is connected; the hoisting winch descends; the opening degree of the adjustable throttle valve 194 is adjusted to be normally closed; changing the flow rate of hydraulic oil through the normally closed adjustable flow valve 194; further controlling the descending speed of the hoisting winch; when the lifting system is normally used, the lifting or descending speed is adjusted according to the load of a lifted object; in the emergency operation, the lowering speed is adjusted by closing the opening degree of the adjustable throttle valve 194. After the object is put down; closing the first normally closed ball valve 192, the second normally closed ball valve 192 and the normally closed adjustable throttle valve 194; the normally open ball valve 195 is opened.

The amplitude changing system comprises a first amplitude changing hydraulic motor 21, a second amplitude changing hydraulic motor 22, a first amplitude changing balance valve 23, a second amplitude changing balance valve 24, an amplitude changing winch 25, an amplitude changing brake mechanism, a first amplitude changing reversing valve 26, an amplitude changing shuttle valve 27, an amplitude changing upper limiting reversing valve 28 and an amplitude changing lower limiting reversing valve 29.

One end of the first variable amplitude hydraulic motor 21 is connected with a first variable amplitude ascending oil path 201; the first variable-amplitude ascending oil path 201 is connected with a control oil port BA 1; the other end of the first luffing hydraulic motor 21 is connected with a first luffing descent oil path 202; the first luffing descent oil passage 202 is connected with a control oil port BB 1. The oil drain port of the first variable amplitude hydraulic motor 21 and the oil drain port of the second variable amplitude hydraulic motor 22 are connected with an oil return path 207; the oil return passage 207 is connected to a control port BL.

The first variable-amplitude ascending oil path 201 is connected with a first variable-amplitude balance valve 23; one end of the second luffing hydraulic motor 22 is connected with a second luffing oil lifting oil path 203; the second variable-amplitude ascending oil way 203 is connected with a control oil port BA 2; the other end of the second variable-amplitude hydraulic motor 22 is connected with a second variable-amplitude descending oil path 204; the second amplitude-variable descending oil way 204 is connected with a control oil port BB 2; the second variable-amplitude ascending oil way 203 is connected with a second variable-amplitude balance valve 24; a first amplitude-variable communication oil way 205 is connected between the first amplitude-variable ascending oil way 201 and the second amplitude-variable ascending oil way 203; the flow rate of the hydraulic oil in the first variable-amplitude ascending oil path 201 is consistent with that of the hydraulic oil in the second variable-amplitude ascending oil path 203; a second amplitude-variable descending oil passage 206 is connected between the first amplitude-variable descending oil passage 202 and the second amplitude-variable descending oil passage 204; the flow rate of the hydraulic oil in the first amplitude-varying descending oil passage 202 is the same as that of the hydraulic oil in the second amplitude-varying descending oil passage 204.

The power output end of the first amplitude-variable hydraulic motor 21 and the power output end of the second amplitude-variable hydraulic motor 22 are respectively connected with an amplitude-variable winch 25, and the amplitude-variable brake mechanism comprises a first amplitude-variable hydraulic brake 31 and a second amplitude-variable hydraulic brake 32; the first luffing hydraulic brake 31 clamps the power output end of the first luffing hydraulic motor 21; the second luffing hydraulic brake 32 clamps the power output of the second luffing hydraulic motor 22; the first luffing hydraulic brake 31 and the second luffing hydraulic brake 32 are both connected to the B5 end of the first luffing reversing valve 26; the A5 end of the first variable amplitude reversing valve 26 is connected with the emergency oil way 208; the P5 end of the first variable amplitude reversing valve 26 is connected with the oil return path 207; the emergency oil way 208 is connected with a control oil port BR 2; the signal end of the first luffing shuttle valve 26 is connected to the output end of the luffing shuttle valve 27. And the control oil port BA1, the control oil port BA2, the control oil port BB1, the control oil port BB2 and the control oil port BL are connected with the oil tank of the pump station.

One input end of the luffing shuttle valve 27 is connected with the B3 end of the luffing upper limiting reversing valve 28; the P3 end of the luffing upper limiting directional valve 28 is connected to the first luffing oil rising passage 201. The other input end of the luffing shuttle valve 27 is connected with the end B4 of the luffing lower limiting reversing valve 29; the P4 end of the amplitude lower limiting directional control valve 29 is connected to the first amplitude lowering oil passage 202. Thus, the lifting and the descending of the amplitude-variable winch 25 can be respectively limited. The end T3 of the amplitude upper limit reversing valve 28 and the end T4 of the amplitude lower limit reversing valve 29 are connected with the oil return passage 207. The end A3 of the upper amplitude limiting directional valve 28 and the end a4 of the lower amplitude limiting directional valve 29 are stopped. In the present embodiment, the amplitude upper limit reversing valve 28 and the amplitude lower limit reversing valve 29 are both two-position four-way mechanical reversing valves.

The first amplitude balance valve 23 comprises a first amplitude one-way valve 231 and a first amplitude overflow valve 232; an oil inlet of the first variable amplitude overflow valve 232 is connected with one end of the first variable amplitude hydraulic motor 21; an oil outlet of the first variable amplitude overflow valve 232 is connected with a control oil port BA 1; a control oil port of the first amplitude-variable overflow valve 232 is connected with the second amplitude-variable descending oil way 204; an oil inlet of the first variable amplitude one-way valve 231 is connected with an oil outlet of the first variable amplitude overflow valve 232; an oil outlet of the first variable amplitude one-way valve 231 is connected with an oil inlet of the first variable amplitude overflow valve 232.

The second amplitude balance valve 24 comprises a second amplitude one-way valve 241 and a second amplitude overflow valve 242; an oil inlet of the second variable amplitude overflow valve 242 is connected with one end of the second variable amplitude hydraulic motor 22; an oil outlet of the second variable amplitude overflow valve 242 is connected with a control oil port BA 2; a control oil port of the second amplitude-variable overflow valve 242 is connected with the second amplitude-variable descending oil path 204; an oil inlet of the second variable amplitude one-way valve 241 is connected with an oil outlet of the second variable amplitude overflow valve 242; the oil outlet of the second variable amplitude one-way valve 241 is connected with the oil inlet of the second variable amplitude overflow valve 242.

A first variable amplitude communicating oil way 205 is arranged; the hydraulic oil in the first amplitude ascending oil path 201 flows into the second amplitude ascending oil path 203; the hydraulic oil in the second amplitude ascending oil path 203 flows into the first amplitude ascending oil path 201; the flow rate of the hydraulic oil in the first variable-amplitude ascending oil path 201 is consistent with that of the hydraulic oil in the second variable-amplitude ascending oil path 203; a second variable amplitude communication oil way 206 is arranged; the hydraulic oil in the first amplitude descending oil path 202 flows into the second amplitude descending oil path 204; the hydraulic oil in the second amplitude descending oil path 204 flows into the first amplitude descending oil path 202; the flow rate of the hydraulic oil in the first amplitude-varying descending oil path 202 is consistent with that of the hydraulic oil in the second amplitude-varying descending oil path 204; thus, the pressure born by the first amplitude ascending oil path 201 and the pressure born by the second amplitude ascending oil path 203 are consistent; the pressure born by the first amplitude-varying descending oil path 202 and the second amplitude-varying descending oil path 204 is consistent; meanwhile, the flow rates of hydraulic oil between the two amplitude ascending oil ways and between the two amplitude ascending oil ways are consistent; the flow rate of hydraulic oil is consistent through the first luffing balance valve 23 and the second balance valve; so that the flow rates of the hydraulic oil respectively entering the first luffing hydraulic motor 21 and the second luffing hydraulic motor 22 are the same; so that the first variable amplitude hydraulic motor 21 and the second variable amplitude hydraulic motor 22 can synchronously rotate; so that the amplitude-variable winch 25 can stably act; while reducing the risk of pressure imbalance in the hydraulic system.

The rotary system 3 comprises a rotary bidirectional balance valve 36, a rotary hydraulic motor 37, a rotary one-way throttle valve 33, a rotary hydraulic control reversing valve 34 and a rotary hydraulic brake 35; the swing bidirectional balanced valve 36 includes a swing first balanced valve 311, a swing second balanced valve 312, and a swing shuttle valve 313; one end of the rotary hydraulic motor 37 is connected to a rotary first oil passage 301; the rotary first oil passage 301 is connected with a control oil port S01; the other end of the rotary hydraulic motor 37 is connected to a rotary second oil passage 302; the rotary first oil passage 301 is connected with a control oil port S02; the oil drain port of the rotary hydraulic motor 37 is connected with a rotary oil drain oil path 303; the rotary oil drainage oil path 303 is connected with a control oil port SL; the control oil port S01, the control oil port S02 and the control oil port SL are connected with the oil tank of the pump station.

The rotary hydraulic motor 37 is also connected with a rotary hydraulic brake 35; a swing first balance valve 311 is provided on the swing first oil passage 301; the rotary second balance valve is arranged on the rotary second oil path 302; one end of the rotary shuttle valve 313 is connected between the control oil port S01 and the rotary first balance valve 311; the other end of the rotary shuttle valve 313 is connected between the control oil port S02 and the rotary second balance valve; the output end of the rotary shuttle valve 313 is connected with the signal end of the rotary hydraulic control balance valve; one end of the rotary hydraulic control reversing valve 34 is connected with the rotary oil drainage oil path 303; the other end of the rotary hydraulic control reversing valve 34 is connected with a rotary emergency oil port BR3 and a rotary hydraulic brake 35; the rotary one-way throttle valve 33 is connected between the rotary pilot operated directional valve 34 and the rotary hydraulic brake 35.

Hydraulic oil output by the pump station oil tank 4 enters the rotary system 3; the hydraulic oil flows into the rotary first oil passage 301 from the control oil port S01; the hydraulic oil flows into the swing first balance valve 311 and the swing shuttle valve 316; hydraulic oil flows to a signal end of the rotary hydraulic control reversing valve; reversing by a rotary hydraulic control reversing valve; hydraulic oil entering from a rotary oil receiving port BR3 flows to a port B6 from a port A6 of the rotary hydraulic control reversing valve, and a rotary hydraulic brake 35 is opened; meanwhile, hydraulic oil in the first rotary oil way flows to the rotary hydraulic motor; then flows out of the rotary second oil way; drives the rotary hydraulic motor 37 to rotate in one direction; when the oil tank 4 of the pump station stops inputting hydraulic oil; reversing by a rotary hydraulic control reversing valve; the rotary hydraulic brake 35 is turned off; the hydraulic oil in the rotary hydraulic brake 35 flows from the port B6 of the rotary hydraulic control directional control valve to the port P6, enters the rotary oil drain oil path 303 and then flows out.

When the hydraulic oil flows into the rotary second oil passage from the control oil port S02; hydraulic oil flows into the rotary second balance valve; hydraulic oil flows to a signal end of the rotary hydraulic control reversing valve; reversing by a rotary hydraulic control reversing valve; hydraulic oil entering from a rotary emergency oil port BR3 opens a rotary hydraulic brake; meanwhile, hydraulic oil in the second rotary oil way flows to the rotary hydraulic motor; then flows out of the first rotary oil way; the rotary hydraulic motor is driven to rotate in the other direction.

The control method comprises a control method of a hoisting system, a control method of a luffing system and a control method of a rotating system;

the control method of the lifting system comprises the following steps:

(1.1) if the hoisting winch is normally hoisted, performing the step (1.2); if the lifting winch descends normally, the step (1.3) is carried out; and (5) operating the hoisting winch, and then performing the step (1.4); .

(1.2) hydraulic oil flows in from a control oil port WA; hydraulic oil enters a lifting variable motor after flowing through a lifting balance valve; then flows out from a control oil port WB; hydraulic oil simultaneously flows through the first lifting shuttle valve; the output end of the lifting shuttle valve I outputs signal oil; the signal oil flows to the lifting reversing valve; reversing the lifting reversing valve; then hydraulic oil flows through a lifting reversing valve from the output end of the first lifting shuttle valve to enter a lifting hydraulic brake, and the brake is opened; the hoisting winch performs a lifting action.

(1.3) hydraulic oil flows in from the control oil port WB; hydraulic oil enters a lifting variable motor; then flows out from a control port WA; hydraulic oil simultaneously flows through the first lifting shuttle valve; the output end of the lifting shuttle valve I outputs signal oil; the signal oil flows to the lifting reversing valve; reversing the lifting reversing valve; then hydraulic oil enters a lifting hydraulic brake from the output end of the lifting shuttle valve I through a lifting reversing valve, and the brake is opened; the hoisting winch performs a lowering action.

(1.4) closing the normally-open ball valve; opening the normally closed ball valve I and the normally closed ball valve II; the manual power device supplies oil to the emergency oil port BR 1; hydraulic oil flows in from an emergency oil port BR 1; flows through a lifting emergency oil way, a lifting emergency descending oil way and a lifting descending oil way; hydraulic oil enters a lifting variable motor; opening a normally closed adjustable throttle valve; hydraulic oil flows through a lifting emergency descending oil way and a lifting descending oil way from one end of the lifting variable motor; then flows to the other end of the lifting variable motor; under the load action of an object connected with a hoisting winch; the hoisting winch performs a lowering action.

According to the method, hydraulic oil flows out from one end of the lifting variable motor and flows through the lifting emergency descending oil way and the lifting descending oil way; then flows to the other end of the lifting variable motor; the lifting variable motor can rotate; under the load action of an object connected with a hoisting winch; the hoisting winch performs a lowering action. Avoiding the power loss of the crane or the failure of the power device; hydraulic oil cannot flow into the control oil port WB; the lifting balance valve cannot be conducted; hydraulic oil output by the lifting variable motor flows out through a lifting oil way; oil pressure exists between the lifting balance valve and the lifting variable motor; the lifting variable motor does not act; situations arise where the hoisting winch cannot be lowered.

The control method of the amplitude changing system comprises the following steps:

(2.1) carrying out the step (2.2) when the amplitude-variable winch carries out lifting action; and (3) descending the amplitude variation winch, and then performing the step (2.3).

(2.2) hydraulic oil flows into the control oil port BA1 and the control oil port BA 2; part of hydraulic oil flows from the first amplitude ascending oil way to the second amplitude ascending oil way; part of the hydraulic oil flows to the first amplitude-variable hydraulic motor through the first amplitude-variable ascending oil way and then flows to the control oil port BB 1; part of the hydraulic oil flows from the second amplitude-variable ascending oil path to the second amplitude-variable hydraulic motor and then flows to the control oil port BB 2; part of the hydraulic oil flows to the first amplitude-variable ascending oil way through the second amplitude-variable ascending oil way; the flow of the hydraulic oil in the first amplitude-variable ascending oil path is consistent with that of the hydraulic oil in the second amplitude-variable ascending oil path.

Part of hydraulic oil flows to the amplitude variation shuttle valve through the amplitude variation upper limiting reversing valve, the first amplitude variation reversing valve reverses, and then the hydraulic oil flows into the first amplitude variation hydraulic brake and the second amplitude variation hydraulic brake to open the brakes; the first amplitude-variable hydraulic motor and the second amplitude-variable hydraulic motor drive the amplitude-variable winch to lift.

(2.3) hydraulic oil flows into the control oil port BB1 and the control oil port BB 2; part of hydraulic oil flows from the first amplitude descending oil way to the second amplitude descending oil way; part of the hydraulic oil flows to the first amplitude-variable hydraulic motor through the first amplitude-variable descending oil way and then flows to the control oil port BA 1; part of the hydraulic oil flows from the second amplitude-variable descending oil way to the second amplitude-variable hydraulic motor and then flows to the control oil port BA 2; part of hydraulic oil flows to the first amplitude-variable descending oil way through the second amplitude-variable descending oil way; the flow of the hydraulic oil in the first amplitude-variable descending oil way is consistent with that of the hydraulic oil in the second amplitude-variable descending oil way.

Part of hydraulic oil flows to the amplitude variation shuttle valve through the amplitude variation lower limiting reversing valve, the first amplitude variation reversing valve reverses, and then the hydraulic oil flows into the first amplitude variation hydraulic brake and the second amplitude variation hydraulic brake to open the brakes; the first amplitude-variable hydraulic motor and the second amplitude-variable hydraulic motor rotate towards the other direction.

In the method, when the amplitude-variable winch carries out lifting action; hydraulic oil input from the first amplitude-variable ascending oil way is input into a signal end of the first amplitude-variable reversing valve; reversing the first variable amplitude reversing valve; hydraulic oil is input from the emergency oil way and flows into a variable amplitude hydraulic brake and a second variable amplitude hydraulic brake to open the brake; meanwhile, hydraulic oil flows from the first amplitude ascending oil way to the first amplitude descending oil way and from the second amplitude ascending oil way to the second amplitude descending oil way; hydraulic oil in the first amplitude-variable ascending oil way flows into the second amplitude-variable ascending oil way; hydraulic oil in the second amplitude-variable ascending oil way flows into the first amplitude-variable ascending oil way; the flow of the hydraulic oil in the first variable-amplitude ascending oil way is consistent with that of the hydraulic oil in the second variable-amplitude ascending oil way; driving the first variable amplitude hydraulic motor and the second variable amplitude hydraulic motor to synchronously rotate; when the amplitude-variable winch descends; hydraulic oil input from the first amplitude-variable descending oil way is input into a signal end of the first amplitude-variable reversing valve; reversing the first variable amplitude reversing valve; hydraulic oil input from the emergency oil way flows into a variable amplitude hydraulic brake and a second variable amplitude hydraulic brake to open the brake; meanwhile, hydraulic oil flows from the first amplitude descending oil way to the first amplitude ascending oil way and from the second amplitude descending oil way to the second amplitude ascending oil way; hydraulic oil in the first amplitude-variable descending oil way flows into the second amplitude-variable descending oil way; hydraulic oil in the second amplitude-variable descending oil way flows into the first amplitude-variable descending oil way; the flow of the hydraulic oil in the first amplitude-variable descending oil way is consistent with that of the hydraulic oil in the second amplitude-variable descending oil way; hydraulic oil in the first amplitude-variable descending oil way flows into the second amplitude-variable descending oil way; hydraulic oil in the second amplitude-variable descending oil way flows into the first amplitude-variable descending oil way; the flow of the hydraulic oil in the first amplitude-variable descending oil way is consistent with that of the hydraulic oil in the second amplitude-variable descending oil way; the first amplitude-variable hydraulic motor and the second amplitude-variable hydraulic motor are driven to synchronously rotate.

The step (2.2) further comprises the following steps: after the amplitude variation upper limiting reversing valve reverses; the oil circuit between the control oil port BA1 and the luffing shuttle valve is disconnected; the first amplitude-variable hydraulic brake and the second amplitude-variable hydraulic brake close the brakes; and stopping the amplitude-changing winch from lifting.

The step (2.3) further comprises: after the amplitude-variable lower limiting reversing valve is reversed; the oil circuit between the control oil port BB1 and the luffing shuttle valve is disconnected; the first amplitude-variable hydraulic brake and the second amplitude-variable hydraulic brake close the brakes; and the amplitude-changing winch stops descending.

The control method of the rotating system comprises the following steps:

(3.1) rotating the rotary hydraulic motor in one direction, and then performing the step (3.2); and (4) rotating the rotary hydraulic motor in the other direction, and then performing the step (3.3).

(3.2) hydraulic oil flows into the rotary first oil path from the control oil port S01; hydraulic oil flows into the rotary first balance valve; hydraulic oil flows to a signal end of the rotary hydraulic control reversing valve; reversing by a rotary hydraulic control reversing valve; hydraulic oil entering from a rotary emergency oil port BR3 opens a rotary hydraulic brake; meanwhile, hydraulic oil in the first rotary oil way flows to the rotary hydraulic motor; then flows out of the rotary second oil way; the rotary hydraulic motor is driven to rotate in one direction.

(3.3) hydraulic oil flows into the rotary second oil path from the control oil port S02; hydraulic oil flows into the rotary second balance valve; hydraulic oil flows to a signal end of the rotary hydraulic control reversing valve; reversing by a rotary hydraulic control reversing valve; hydraulic oil entering from a rotary emergency oil port BR3 opens a rotary hydraulic brake; meanwhile, hydraulic oil in the second rotary oil way flows to the rotary hydraulic motor; then flows out of the first rotary oil way; the rotary hydraulic motor is driven to rotate in the other direction.

Claims

1. A hydraulic system of a crane; the method is characterized in that: the device comprises a lifting system, a rotating system, a variable amplitude system, a pump station oil tank and a multi-way valve; the pump station oil tank is communicated with the lifting system, the rotating system, the amplitude varying system and the multi-way valve; the pump station oil tank supplies oil to the multi-way valve, the amplitude varying system, the lifting system and the rotating system respectively; a manual power device is connected between the pump station oil tank and the lifting system, between the pump station oil tank and the rotary system and between the pump station oil tank and the amplitude varying system;

the lifting system comprises a lifting winch, a lifting variable motor, a lifting balance valve, a normally closed ball valve I, a normally closed ball valve II, a normally closed adjustable throttle valve and a normally open ball valve; one end of the lifting variable motor is connected with a lifting oil way; a lifting oil circuit is connected with a control oil port WA; a lifting balance valve is connected to the lifting oil path; the other end of the lifting variable motor is connected with a lifting descending oil way; the lifting and descending oil way is connected with a control oil port WB; the lifting and descending oil way is connected with a normally open ball valve; a lifting emergency descending oil way is connected between the lifting ascending oil way and the lifting descending oil way; one end of the lifting emergency descending oil way is connected between the lifting balance valve and the lifting variable motor; the other end of the lifting emergency descending oil way is arranged between the lifting variable motor and the normally-open ball valve; a normally closed adjustable throttle valve and a normally closed ball valve II are sequentially connected to the lifting emergency descending oil circuit; a lifting emergency oil way is connected between the normally closed ball valve II and the lifting emergency descending oil way; the lifting emergency oil way is connected with an emergency oil port BR 1; the oil drain port of the lifting variable motor is connected with a lifting oil return path; the lifting oil return oil path is connected with an oil return port WL; the power output end of the lifting variable motor is connected with a lifting winch; the manual power device is connected with an emergency oil port BR 1;

the amplitude varying system comprises a first amplitude varying hydraulic motor, a second amplitude varying hydraulic motor, a first amplitude varying balance valve, a second amplitude varying balance valve, an amplitude varying winch, an amplitude varying brake mechanism, a first amplitude varying reversing valve and an amplitude varying shuttle valve; the power output end of the first variable-amplitude hydraulic motor and the power output end of the second variable-amplitude hydraulic motor are respectively connected with a variable-amplitude winch; one end of the first variable amplitude hydraulic motor is connected with a first variable amplitude ascending oil way; the first variable-amplitude ascending oil way is connected with a control oil port BA 1; the other end of the first variable amplitude hydraulic motor is connected with a first variable amplitude descending oil way; the first amplitude-variable descending oil way is connected with a control oil port BB 1; the first amplitude-variable ascending oil way is connected with a first amplitude-variable balance valve; one end of the second variable-amplitude hydraulic motor is connected with a second variable-amplitude ascending oil way; the second variable-amplitude ascending oil way is connected with a control oil port BA 2; the other end of the second variable-amplitude hydraulic motor is connected with a second variable-amplitude descending oil way; the second amplitude-variable descending oil way is connected with a control oil port BB 2; a second variable-amplitude ascending oil path is connected with a second variable-amplitude balance valve; a first variable-amplitude oil-communicating passage is connected between the first variable-amplitude oil-rising passage and the second variable-amplitude oil-rising passage; the flow of the hydraulic oil in the first variable-amplitude ascending oil way is consistent with that of the hydraulic oil in the second variable-amplitude ascending oil way; a second variable-amplitude descending oil way is connected between the first variable-amplitude descending oil way and the second variable-amplitude descending oil way; the flow of the hydraulic oil in the first amplitude-variable descending oil way is consistent with that of the hydraulic oil in the second amplitude-variable descending oil way;

2. The hydraulic system of a hoist as claimed in claim 1, wherein: the lifting system also comprises a lifting hydraulic brake, a lifting shuttle valve I, a lifting reversing valve and a lifting limiting reversing valve; the lifting hydraulic brake is connected with the output end of the lifting variable motor in a clamping manner; the output end of the lifting shuttle valve I is connected with the signal end of the lifting reversing valve and one end of the lifting reversing valve; one end of the lifting reversing valve is also connected with a lifting hydraulic brake; the other end of the lifting reversing valve is connected with a lifting oil return path; one input end of the lifting shuttle valve I is connected with one end of the lifting limiting reversing valve; the other end of the lifting limiting reversing valve is connected with a lifting oil way and an oil tank; the other input end of the first lifting shuttle valve is connected with a lifting descending oil way.

3. The hydraulic system of a hoist as claimed in claim 2, wherein: the lifting balance valve comprises a lifting one-way valve and a lifting overflow valve; an oil inlet of the lifting overflow valve is connected with one end of a lifting variable motor; an oil outlet of the lifting overflow valve is connected with a control oil port WA; a control oil port of the lifting overflow valve is connected with a lifting descending oil way; an oil inlet of the lifting one-way valve is connected with an oil outlet of the lifting overflow valve; and a lifting one-way throttle valve is connected between a control oil port of the lifting overflow valve and the lifting descending oil way.

4. The hydraulic system of a hoist as claimed in claim 2, wherein: the lifting system also comprises a second lifting shuttle valve and a lifting pressure reducing valve; the lifting variable motor is provided with a variable mechanism; one input end of the lifting shuttle valve II is connected with a control oil port WA; the other input end of the lifting shuttle valve II is connected with a control oil port WB; the output end of the second lifting shuttle valve is connected with the oil inlet of the lifting pressure reducing valve; an oil outlet of the lifting pressure reducing valve is connected with a variable mechanism; the oil drain port of the lifting pressure reducing valve is connected with the oil tank.

5. The hydraulic system of a hoist as claimed in claim 1, wherein: the amplitude-variable brake mechanism comprises a first amplitude-variable hydraulic brake and a second amplitude-variable hydraulic brake; the first amplitude-variable hydraulic brake clamps the power output end of the first amplitude-variable hydraulic motor; the second variable amplitude hydraulic brake clamps the power output end of the second variable amplitude hydraulic motor; the first amplitude-variable hydraulic brake and the second amplitude-variable hydraulic brake are both connected with one end of the first amplitude-variable reversing valve; the other end of the first variable amplitude reversing valve is connected with an emergency oil way; the emergency oil way is connected with a control oil port BR 2; the signal end of the first amplitude-changing reversing valve is connected with the output end of the amplitude-changing shuttle valve; one input end of the amplitude-variable shuttle valve is connected with the first amplitude-variable ascending oil way; the other input end of the amplitude-variable shuttle valve is connected with the first amplitude-variable descending oil way.

6. The hydraulic system of a hoist as claimed in claim 5, wherein: the amplitude varying system also comprises an amplitude varying upper limiting reversing valve and an amplitude varying lower limiting reversing valve; the amplitude variation upper limiting reversing valve is connected between the amplitude variation shuttle valve and the first amplitude variation ascending oil way; the amplitude-variable lower limiting reversing valve is connected between the amplitude-variable shuttle valve and the first amplitude-variable descending oil way.

7. A hydraulic system of a crane according to claim 3; the method is characterized in that: an oil drain port of the first variable-amplitude hydraulic motor, an oil drain port of the second variable-amplitude hydraulic motor, one end of the first variable-amplitude reversing valve, one end of the variable-amplitude upper limiting reversing valve and one end of the variable-amplitude lower limiting reversing valve are connected with an oil return way; the oil return oil way is connected with a control oil port BL.

8. A hydraulic system of a crane according to claim 1; the method is characterized in that: the first amplitude-variable balance valve comprises a first amplitude-variable one-way valve and a first amplitude-variable overflow valve; an oil inlet of the first variable amplitude overflow valve is connected with one end of the first variable amplitude hydraulic motor; an oil outlet of the first variable amplitude overflow valve is connected with a control oil port BA 1; a control oil port of the first variable-amplitude overflow valve is connected with the second variable-amplitude descending oil way; an oil inlet of the first variable amplitude one-way valve is connected with an oil outlet of the first variable amplitude overflow valve; an oil outlet of the first variable amplitude one-way valve is connected with an oil inlet of the first variable amplitude overflow valve; the second amplitude-variable balance valve comprises a second amplitude-variable one-way valve and a second amplitude-variable overflow valve; an oil inlet of the second variable amplitude overflow valve is connected with one end of the second variable amplitude hydraulic motor; an oil outlet of the second variable-amplitude overflow valve is connected with a control oil port BA 2; a control oil port of the second variable-amplitude overflow valve is connected with the second variable-amplitude descending oil way; an oil inlet of the second variable amplitude one-way valve is connected with an oil outlet of the second variable amplitude overflow valve; an oil outlet of the second variable amplitude one-way valve is connected with an oil inlet of the second variable amplitude overflow valve.